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Impairment in renal medulla development underlies salt wasting in Clc-k2 channel deficiency
Lin et al. explore the roles the chloride ion channel and transporters Clc-k1 and Clc-k2 in the thick ascending limb and renal medulla development. The cover image shows immunolabeled thick ascending limb of Henle’s loop from mouse kidney visualized using light-sheet fluorescent microscopy to detect sodium-potassium-chloride co-transporter type 2.
Failed or altered gliogenesis is a major characteristic of diffuse white matter injury in survivors of premature birth. The developmentally regulated long noncoding RNA (lncRNA) H19 inhibits S-adenosylhomocysteine hydrolase (SAHH) and contributes to methylation of diverse cellular components, such as DNA, RNA, proteins, lipids, and neurotransmitters. We showed that the pregnancy-derived synthetic PreImplantation Factor (sPIF) induces expression of the nuclear receptor corepressor 2 (NCOR2) via H19/SAHH-mediated DNA demethylation. In turn, NCOR2 affects oligodendrocyte differentiation markers. Accordingly, after hypoxic-ischemic brain injury in rodents, myelin protection and oligodendrocytes’ fate are in part modulated by sPIF and H19. Our results revealed an unexpected mechanism of the H19/SAHH axis underlying myelin preservation during brain recovery and its use in treating neurodegenerative diseases can be envisioned.
Marialuigia Spinelli, Celiné Boucard, Sara Ornaghi, Andreina Schoeberlein, Keller Irene, Daniel Coman, Fahmeed Hyder, Longbo Zhang, Valérie Haesler, Angelique Bordey, Eytan Barnea, Michael Paidas, Daniel Surbek, Martin Mueller
During pregnancy, fetal glucose production is suppressed, with rapid activation immediately postpartum. Fatty acid–binding protein 4 (FABP4) was recently demonstrated as a regulator of hepatic glucose production and systemic metabolism in animal models. Here, we studied the role of FABP4 in regulating neonatal glucose hemostasis. Serum samples were collected from pregnant women with normoglycemia or gestational diabetes at term, from the umbilical circulation, and from the newborns within 6 hours of life. The level of FABP4 was higher in the fetal versus maternal circulation, with a further rise in neonates after birth of approximately 3-fold. Neonatal FABP4 inversely correlated with blood glucose, with an approximately 10-fold increase of FABP4 in hypoglycemic neonates. When studied in mice, blood glucose of 12-hour-old WT, Fabp4–/+, and Fabp4–/– littermate mice was 59 ± 13 mg/dL, 50 ± 11 mg/dL, and 43 ± 11 mg/dL, respectively. Similar to our observations in humans, FABP4 levels in WT mouse neonates were approximately 8-fold higher compared with those in adult mice. RNA sequencing of the neonatal liver suggested altered expression of multiple glucagon-regulated pathways in Fabp4–/– mice. Indeed, Fabp4–/– liver glycogen was inappropriately intact, despite a marked hypoglycemia, with rapid restoration of normoglycemia upon injection of recombinant FABP4. Our data suggest an important biological role for the adipokine FABP4 in the orchestrated regulation of postnatal glucose metabolism.
Idit Ron, Reut Kassif Lerner, Moran Rathaus, Rinat Livne, Sophie Ron, Ehud Barhod, Rina Hemi, Amit Tirosh, Tzipora Strauss, Keren Ofir, Ido Goldstein, Itai M. Pessach, Amir Tirosh
BACKGROUND Neighborhood-level socioeconomic disadvantage has wide-ranging impacts on health outcomes, particularly in older adults. Although indices of disadvantage are a widely used tool, research conducted to date has not codified a set of standard variables that should be included in these indices for the United States. The objective of this study was to conduct a systematic review of literature describing the construction of geographic indices of neighborhood-level disadvantage and to summarize and distill the key variables included in these indices. We also sought to demonstrate the utility of these indices for understanding neighborhood-level disadvantage in older adults.METHODS We conducted a systematic review of existing indices in the English-language literature.RESULTS We identified 6021 articles, of which 130 met final study inclusion criteria. Our review identified 7 core domains across the surveyed papers, including income, education, housing, employment, neighborhood structure, demographic makeup, and health. Although not universally present, the most prevalent variables included in these indices were education and employment.CONCLUSION Identifying these 7 core domains is a key finding of this review. These domains should be considered for inclusion in future neighborhood-level disadvantage indices, and at least 5 domains are recommended to improve the strength of the resulting index. Targeting specific domains offers a path forward toward the construction of a new US-specific index of neighborhood disadvantage with health policy applications. Such an index will be especially useful for characterizing the life-course impact of lived disadvantage in older adults.
William R. Buckingham, Lauren Bishop, Christopher Hooper-Lane, Brittany Anderson, Jessica Wolfson, Stephanie Shelton, Amy J.H. Kind
Monocarboxylates, such as lactate and pyruvate, are precursors for biosynthetic pathways, including those for glucose, lipids, and amino acids via the tricarboxylic acid (TCA) cycle and adjacent metabolic networks. The transportation of monocarboxylates across the cellular membrane is performed primarily by monocarboxylate transporters (MCTs), the membrane localization and stabilization of which are facilitated by the transmembrane protein basigin (BSG). Here, we demonstrate that the MCT/BSG axis sits at a crucial intersection of cellular metabolism. Abolishment of MCT1 in the plasma membrane was achieved by Bsg depletion, which led to gluconeogenesis impairment via preventing the influx of lactate and pyruvate into the cell, consequently suppressing the TCA cycle. This net anaplerosis suppression was compensated in part by the increased utilization of glycogenic amino acids (e.g., alanine and glutamine) into the TCA cycle and by activated ketogenesis through fatty acid β-oxidation. Complementary to these observations, hyperglycemia and hepatic steatosis induced by a high-fat diet were ameliorated in Bsg-deficient mice. Furthermore, Bsg deficiency significantly improved insulin resistance induced by a high-fat diet. Taken together, the plasma membrane–selective modulation of lactate and pyruvate transport through BSG inhibition could potentiate metabolic flexibility to treat metabolic diseases.
Loss of the maternal UBE3A allele causes Angelman syndrome (AS), a debilitating neurodevelopmental disorder. Here, we devised an AS treatment strategy based on reinstating dual-isoform expression of human UBE3A (hUBE3A) in the developing brain. Kozak sequence engineering of our codon-optimized vector (hUBE3Aopt) enabled translation of both short and long hUBE3A protein isoforms at a near-endogenous 3:1 (short/long) ratio, a feature that could help to support optimal therapeutic outcomes. To model widespread brain delivery and early postnatal onset of hUBE3A expression, we packaged the hUBE3Aopt vector into PHP.B capsids and performed intracerebroventricular injections in neonates. This treatment significantly improved motor learning and innate behaviors in AS mice, and it rendered them resilient to epileptogenesis and associated hippocampal neuropathologies induced by seizure kindling. hUBE3A overexpression occurred frequently in the hippocampus but was uncommon in the neocortex and other major brain structures; furthermore, it did not correlate with behavioral performance. Our results demonstrate the feasibility, tolerability, and therapeutic potential for dual-isoform hUBE3A gene transfer in the treatment of AS.
Matthew C. Judson, Charles Shyng, Jeremy M. Simon, Courtney R. Davis, A. Mattijs Punt, Mirabel T. Salmon, Noah W. Miller, Kimberly D. Ritola, Ype Elgersma, David G. Amaral, Steven J. Gray, Benjamin D. Philpot
Mutations in the cilium-associated protein CEP290 cause retinal degeneration as part of multiorgan ciliopathies or as retina-specific diseases. The precise location and the functional roles of CEP290 within cilia and, specifically, the connecting cilia (CC) of photoreceptors, remain unclear. We used super-resolution fluorescence microscopy and electron microscopy to localize CEP290 in the CC and in the primary cilia of cultured cells with subdiffraction resolution and to determine effects of CEP290 deficiency in 3 mutant models. Radially, CEP290 localizes in close proximity to the microtubule doublets in the region between the doublets and the ciliary membrane. Longitudinally, it is distributed throughout the length of the CC whereas it is confined to the very base of primary cilia in human retinal pigment epithelium-1 cells. We found Y-shaped links, ciliary substructures between microtubules and membrane, throughout the length of the CC. Severe CEP290 deficiencies in mouse models did not prevent assembly of cilia or cause obvious mislocalization of ciliary components in early stages of degeneration. There were fewer cilia and no normal outer segments in the mutants, but the Y-shaped links were clearly present. These results point to photoreceptor-specific functions of CEP290 essential for CC maturation and stability following the earliest stages of ciliogenesis.
Valencia L. Potter, Abigail R. Moye, Michael A. Robichaux, Theodore G. Wensel
Macrophage proinflammatory activation is an important etiologic component of the development of insulin resistance and metabolic dysfunction in obesity. However, the underlying mechanisms are not clearly understood. Here, we demonstrate that a mitochondrial inner membrane protein, adenine nucleotide translocase 2 (ANT2), mediates proinflammatory activation of adipose tissue macrophages (ATMs) in obesity. Ant2 expression was increased in ATMs of obese mice compared with lean mice. Myeloid-specific ANT2-knockout (ANT2-MKO) mice showed decreased adipose tissue inflammation and improved insulin sensitivity and glucose tolerance in HFD/obesity. At the molecular level, we found that ANT2 mediates free fatty acid–induced mitochondrial permeability transition, leading to increased mitochondrial reactive oxygen species production and damage. In turn, this increased HIF-1α expression and NF-κB activation, leading to proinflammatory macrophage activation. Our results provide a previously unknown mechanism for how obesity induces proinflammatory activation of macrophages with propagation of low-grade chronic inflammation (metaflammation).
Jae-Su Moon, Flavia Franco da Cunha, Jin Young Huh, Alexander Yu Andreyev, Jihyung Lee, Sushil K. Mahata, Felipe C.G. Reis, Chanond A. Nasamran, Yun Sok Lee
Autophagy has long been associated with longevity, and it is well established that autophagy reverts and prevents vascular deterioration associated with aging and cardiovascular diseases. Currently, our understanding of how autophagy benefits the vasculature is centered on the premise that reduced autophagy leads to the accumulation of cellular debris, resulting in inflammation and oxidative stress, which are then reversed by reconstitution or upregulation of autophagic activity. Evolutionarily, autophagy also functions to mobilize endogenous nutrients in response to starvation. Therefore, we hypothesized that the biosynthesis of the most physiologically abundant ketone body, β-hydroxybutyrate (βHB), would be autophagy dependent and exert vasodilatory effects via its canonical receptor, Gpr109a. To the best of our knowledge, we have revealed for the first time that the biosynthesis of βHB can be impaired by preventing autophagy. Subsequently, βHB caused potent vasodilation via potassium channels but not Gpr109a. Finally, we observed that chronic consumption of a high-salt diet negatively regulates both βHB biosynthesis and hepatic autophagy and that reconstitution of βHB bioavailability prevents high-salt diet–induced endothelial dysfunction. In summary, this work offers an alternative mechanism to the antiinflammatory and antioxidative stress hypothesis of autophagy-dependent vasculoprotection. Furthermore, it reveals a direct mechanism by which ketogenic interventions (e.g., intermittent fasting) improve vascular health.
Cameron G. McCarthy, Saroj Chakraborty, Gagandeep Singh, Beng San Yeoh, Zachary J. Schreckenberger, Avinash Singh, Blair Mell, Nicole R. Bearss, Tao Yang, Xi Cheng, Matam Vijay-Kumar, Camilla F. Wenceslau, Bina Joe
Polarization of low-grade inflammatory monocytes facilitates the pathogenesis of atherosclerosis. However, underlying mechanisms as well as approaches for resolving monocyte polarization conducive to the regression of atherosclerosis are not well established. In this report, we demonstrate that TRIF-related adaptor molecule (TRAM) mediated monocyte polarization in vivo and in vitro. TRAM controlled monocyte polarization through activating Src family kinase c-SRC, which not only induces STAT1/STAT5-regulated inflammatory mediators CCR2 and SIRP-α but also suppresses PPARγ-regulated resolving mediator CD200R. Enhanced PPARγ and Pex5 due to TRAM deficiency facilitated peroxisome homeostasis and reduction of cellular reactive oxygen species, further contributing to the establishment of a resolving monocyte phenotype. TRAM-deficient monocytes propagated the resolving phenotype to neighboring monocytes through CD200R-mediated intercellular communication. At the translational level, we show that TRAM-deficient mice were resistant to high-fat diet–induced pathogenesis of atherosclerosis. We further document that intravenous transfusion of TRAM-deficient resolving monocytes into atherosclerotic mice potently reduced the progression of atherosclerosis. Together, our data reveal that targeting TRAM may facilitate the effective generation of resolving monocytes conducive for the treatment of atherosclerosis.
BACKGROUND Genetics of estrogen synthesis and breast cancer risk has been elusive. The 1245A→C missense-encoding polymorphism in HSD3B1, which is common in White populations, is functionally adrenal permissive and increases synthesis of the aromatase substrate androstenedione. We hypothesized that homozygous inheritance of the adrenal-permissive HSD3B1(1245C) is associated with postmenopausal estrogen receptor–positive (ER-positive) breast cancer.METHODS A prospective study of postmenopausal ER-driven breast cancer was done for determination of HSD3B1 and circulating steroids. Validation was performed in 2 other cohorts. Adrenal-permissive genotype frequency was compared between postmenopausal ER-positive breast cancer, the general population, and postmenopausal ER-negative breast cancer.RESULTS Prospective and validation studies had 157 and 538 patients, respectively, for the primary analysis of genotype frequency by ER status in White female breast cancer patients who were postmenopausal at diagnosis. The adrenal-permissive genotype frequency in postmenopausal White women with estrogen-driven breast cancer in the prospective cohort was 17.5% (21/120) compared with 5.4% (2/37) for ER-negative breast cancer (P = 0.108) and 9.6% (429/4451) in the general population (P = 0.0077). Adrenal-permissive genotype frequency for estrogen-driven postmenopausal breast cancer was validated using Cambridge and The Cancer Genome Atlas data sets: 14.4% (56/389) compared with 6.0% (9/149) for ER-negative breast cancer (P = 0.007) and the general population (P = 0.005). Circulating androstenedione concentration was higher with the adrenal-permissive genotype (P = 0.03).CONCLUSION Adrenal-permissive genotype is associated with estrogen-driven postmenopausal breast cancer. These findings link genetic inheritance of endogenous estrogen exposure to estrogen-driven breast cancer.FUNDING National Cancer Institute, NIH (R01CA236780, R01CA172382, and P30-CA008748); and Prostate Cancer Foundation Challenge Award.
Megan L. Kruse, Mona Patel, Jeffrey McManus, Yoon-Mi Chung, Xiuxiu Li, Wei Wei, Peter S. Bazeley, Fumihiko Nakamura, Aimalie Hardaway, Erinn Downs, Sarat Chandarlapaty, Mathew Thomas, Halle C.F. Moore, George T. Budd, W.H. Wilson Tang, Stanley L. Hazen, Aaron Bernstein, Serena Nik-Zainal, Jame Abraham, Nima Sharifi
Infection is a common complication of major trauma that causes significantly increased morbidity and mortality. The mechanisms, however, linking tissue injury to increased susceptibility to infection remain poorly understood. To study this relationship, we present a potentially novel murine model in which a major liver crush injury is followed by bacterial inoculation into the lung. We find that such tissue trauma both impaired bacterial clearance and was associated with significant elevations in plasma heme levels. While neutrophil (PMN) recruitment to the lung in response to Staphylococcus aureus was unchanged after trauma, PMN cleared bacteria poorly. Moreover, PMN show > 50% less expression of TLR2, which is responsible, in part, for bacterial recognition. Administration of heme effectively substituted for trauma. Finally, day 1 trauma patients (n = 9) showed similar elevations in free heme compared with that seen after murine liver injury, and circulating PMN showed similar TLR2 reduction compared with volunteers (n = 6). These findings correlate to high infection rates.
Ghee Rye Lee, David Gallo, Rodrigo W. Alves de Souza, Shilpa Tiwari-Heckler, Eva Csizmadia, James D. Harbison, Sidharth Shankar, Valerie Banner-Goodspeed, Michael B. Yaffe, Maria Serena Longhi, Carl J. Hauser, Leo E. Otterbein
Natural aging and HIV infection are associated with chronic low-grade systemic inflammation, immune senescence, and impaired antibody responses to vaccines such as the influenza (flu) vaccine. We investigated the role of IL-21, a CD4+ T follicular helper cell (Tfh) regulator, on flu vaccine antibody response in nonhuman primates (NHPs) in the context of age and controlled SIV mac239 infection. Three doses of the flu vaccine with or without IL-21–IgFc were administered at 3-month intervals in aged SIV+ NHPs following virus suppression with antiretroviral therapy. IL-21–treated animals demonstrated higher day 14–postboost antibody responses, which associated with expanded CD4+ T central memory cells and peripheral Tfh–expressing (pTfh–expressing) T cell immunoreceptor with Ig and ITIM domains (TIGIT), expanded activated memory B cells, and contracted CD11b+ monocytes. Draining lymph node (LN) tissue from IL-21–treated animals revealed direct association between LN follicle Tfh density and frequency of circulating TIGIT+ pTfh cells. We conclude that IL-21 enhances flu vaccine–induced antibody responses in SIV+ aged rhesus macaques (RMs), acting as an adjuvant modulating LN germinal center activity. A strategy to supplement IL-21 in aging could be a valuable addition in the toolbox for improving vaccine responses in an aging HIV+ population.
Daniel Kvistad, Suresh Pallikkuth, Tirupataiah Sirupangi, Rajendra Pahwa, Alexander Kizhner, Constantinos Petrovas, Francois Villinger, Savita Pahwa
Only a subset of cancer patients responds to checkpoint blockade inhibition in the clinic. Strategies to overcome resistance are promising areas of investigation. Targeting glucocorticoid-induced tumor necrosis factor receptor–related protein (GITR) has shown efficacy in preclinical models, but GITR engagement is ineffective in controlling advanced, poorly immunogenic tumors, such as B16 melanoma, and has not yielded benefit in clinical trials. The alkylating agent cyclophosphamide (CTX) depletes regulatory T cells (Tregs), expands tumor-specific effector T cells (Teffs) via homeostatic proliferation, and induces immunogenic cell death. GITR agonism has an inhibitory effect on Tregs and activates Teffs. We therefore hypothesized that CTX and GITR agonism would promote effective antitumor immunity. Here we show that the combination of CTX and GITR agonism controlled tumor growth in clinically relevant mouse models. Mechanistically, we show that the combination therapy caused tumor cell death, clonal expansion of highly active CD8+ T cells, and depletion of Tregs by activation-induced cell death. Control of tumor growth was associated with the presence of an expanded population of highly activated, tumor-infiltrating, oligoclonal CD8+ T cells that led to a diminished TCR repertoire. Our studies show that the combination of CTX and GITR agonism is a rational chemoimmunotherapeutic approach that warrants further clinical investigation.
Daniel Hirschhorn, Allison Betof Warner, Rachana Maniyar, Andrew Chow, Levi M.B. Mangarin, Adam D. Cohen, Linda Hamadene, Gabrielle A. Rizzuto, Sadna Budhu, Nathan Suek, Cailian Liu, Alan N. Houghton, Taha Merghoub, Jedd D. Wolchok
The prevailing view is that the ClC-Ka chloride channel (mouse Clc-k1) functions in the thin ascending limb to control urine concentration, whereas the ClC-Kb channel (mouse Clc-k2) functions in the thick ascending limb (TAL) to control salt reabsorption. Mutations of ClC-Kb cause classic Bartter syndrome, characterized by renal salt wasting, with perinatal to adolescent onset. We studied the roles of Clc-k channels in perinatal mouse kidneys using constitutive or inducible kidney-specific gene ablation and 2D and advanced 3D imaging of optically cleared kidneys. We show that Clc-k1 and Clc-k2 were broadly expressed and colocalized in perinatal kidneys. Deletion of Clc-k1 and Clc-k2 revealed that both participated in NKCC2- and NCC-mediated NaCl reabsorption in neonatal kidneys. Embryonic deletion of Clc-k2 caused tubular injury and impaired renal medulla and TAL development. Inducible deletion of Clc-k2 beginning after medulla maturation produced mild salt wasting resulting from reduced NCC activity. Thus, both Clc-k1 and Clc-k2 contributed to salt reabsorption in TAL and distal convoluted tubule (DCT) in neonates, potentially explaining the less-severe phenotypes in classic Bartter syndrome. As opposed to the current understanding that salt wasting in adult patients with Bartter syndrome is due to Clc-k2 deficiency in adult TAL, our results suggest that it originates mainly from defects occurring in the medulla and TAL during development.
Dry eye disease affects over 16 million adults in the US, and the majority of cases are due to Meibomian gland dysfunction. Unfortunately, the identity of the stem cells involved in Meibomian gland development and homeostasis is not well elucidated. Here, we report that loss of Krox20, a zinc finger transcription factor involved in the development of ectoderm-derived tissues, or deletion of KROX20-expressing epithelial cells disrupted Meibomian gland formation and homeostasis, leading to dry eye disease secondary to Meibomian gland dysfunction. Ablation of Krox20-lineage cells in adult mice also resulted in dry eye disease, implicating Krox20 in homeostasis of the mature Meibomian gland. Lineage-tracing and expression analyses revealed a restricted KROX20 expression pattern in the ductal areas of the Meibomian gland, although Krox20-lineage cells generate the full, mature Meibomian gland. This suggests that KROX20 marks a stem/progenitor cell population that differentiates to generate the entire Meibomian gland. Our Krox20 mouse models provide a powerful system that delineated the identity of stem cells required for Meibomian gland development and homeostasis and can be used to investigate the factors underlying these processes. They are also robust models of Meibomian gland dysfunction–related dry eye disease, with a potential for use in preclinical therapeutic screening.
Edem Tchegnon, Chung-Ping Liao, Elnaz Ghotbi, Tracey Shipman, Yong Wang, Renee M. McKay, Lu Q. Le
Longitudinal studies are needed to evaluate the SARS-CoV-2 mRNA vaccine antibody response under real-world conditions. This longitudinal study investigated the quantity and quality of SARS-CoV-2 antibody response in 846 specimens from 350 patients, comparing BNT162b2-vaccinated individuals (19 previously diagnosed with COVID-19, termed RecoVax; and 49 never diagnosed, termed NaiveVax) with 122 hospitalized unvaccinated (HospNoVax) and 160 outpatient unvaccinated (OutPtNoVax) COVID-19 patients. NaiveVax experienced delay in generating SARS-CoV-2 total antibodies (TAb) and surrogate neutralizing antibodies (SNAb) after the first vaccine dose (D1) but rapid increase in antibody levels after the second dose (D2). However, these never reached RecoVax’s robust levels. In fact, NaiveVax TAb and SNAb levels decreased 4 weeks after D2. For the most part, RecoVax TAb persisted, after reaching maximal levels 2 weeks after D2, but SNAb decreased significantly about 6 months after D1. Although NaiveVax avidity lagged behind that of RecoVax for most of the follow-up periods, NaiveVax did reach similar avidity by about 6 months after D1. These data suggest that 1 vaccine dose elicits maximal antibody response in RecoVax and may be sufficient. Also, despite decreasing levels in TAb and SNAb over time, long-term avidity may be a measure worth evaluating and possibly correlating to vaccine efficacy.
Sabrina E. Racine-Brzostek, Jim K. Yee, Ashley Sukhu, Yuqing Qiu, Sophie Rand, Paul D. Barone, Ying Hao, He S. Yang, Qing H. Meng, Fred S. Apple, Yuanyuan Shi, Amy Chadburn, Encouse Golden, Silvia C. Formenti, Melissa M. Cushing, Zhen Zhao
Endothelial dysfunction accompanies the microvascular thrombosis commonly observed in severe COVID-19. Constitutively, the endothelial surface is anticoagulant, a property maintained at least in part via signaling through the Tie2 receptor. During inflammation, the Tie2 antagonist angiopoietin-2 (Angpt-2) is released from endothelial cells and inhibits Tie2, promoting a prothrombotic phenotypic shift. We sought to assess whether severe COVID-19 is associated with procoagulant endothelial dysfunction and alterations in the Tie2/angiopoietin axis. Primary HUVECs treated with plasma from patients with severe COVID-19 upregulated the expression of thromboinflammatory genes, inhibited the expression of antithrombotic genes, and promoted coagulation on the endothelial surface. Pharmacologic activation of Tie2 with the small molecule AKB-9778 reversed the prothrombotic state induced by COVID-19 plasma in primary endothelial cells. Lung autopsies from patients with COVID-19 demonstrated a prothrombotic endothelial signature. Assessment of circulating endothelial markers in a cohort of 98 patients with mild, moderate, or severe COVID-19 revealed endothelial dysfunction indicative of a prothrombotic state. Angpt-2 concentrations rose with increasing disease severity, and the highest levels were associated with worse survival. These data highlight the disruption of Tie2/angiopoietin signaling and procoagulant changes in endothelial cells in severe COVID-19. Our findings provide rationale for current trials of Tie2-activating therapy with AKB-9778 in COVID-19.
Alec A. Schmaier, Gabriel M. Pajares Hurtado, Zachary J. Manickas-Hill, Kelsey D. Sack, Siyu M. Chen, Victoria Bhambhani, Juweria Quadir, Anjali K. Nath, Ai-ris Y. Collier, Debby Ngo, Dan H. Barouch, Nathan I. Shapiro, Robert E. Gerszten, Xu G. Yu, MGH COVID-19 Collection and Processing Team, Kevin G. Peters, Robert Flaumenhaft, Samir M. Parikh
Altered epidermal differentiation along with increased keratinocyte proliferation is a characteristic feature of psoriasis and pityriasis rubra pilaris (PRP). However, despite this large degree of overlapping clinical and histologic features, the molecular signatures these skin disorders share are unknown. Using global transcriptomic profiling, we demonstrate that plaque psoriasis and PRP skin lesions have high overlap, with all differentially expressed genes in PRP relative to normal skin having complete overlap with those in psoriasis. The major common pathway shared between psoriasis and PRP involves the phospholipases PLA2G2F, PLA2G4D, and PLA2G4E, which were found to be primarily expressed in the epidermis. Gene silencing each of the 3 PLA2s led to reduction in immune responses and epidermal thickness both in vitro and in vivo in a mouse model of psoriasis, establishing their proinflammatory roles. Lipidomic analyses demonstrated that PLA2s affect mobilization of a phospholipid-eicosanoid pool, which is altered in psoriatic lesions and functions to promote immune responses in keratinocytes. Taken together, our results highlight the important role of PLA2s as regulators of epidermal barrier homeostasis and inflammation, identify PLA2s as a shared pathogenic mechanism between PRP and psoriasis, and as potential therapeutic targets for both diseases.
Shuai Shao, Jiaoling Chen, William R. Swindell, Lam C. Tsoi, Xianying Xing, Feiyang Ma, Ranjitha Uppala, Mrinal K. Sarkar, Olesya Plazyo, Allison C. Billi, Rachael Wasikowski, Kathleen M. Smith, Prisca Honore, Victoria E. Scott, Emanual Maverakis, J. Michelle Kahlenberg, Gang Wang, Nicole L. Ward, Paul W. Harms, Johann E. Gudjonsson
The epidermal growth factor receptor (EGFR) inhibitor cetuximab is the only FDA-approved oncogene-targeting therapy for head and neck squamous cell carcinoma (HNSCC). Despite variable treatment response, no biomarkers exist to stratify patients for cetuximab therapy in HNSCC. Here, we applied unbiased hierarchical clustering to reverse-phase protein array molecular profiles from patient-derived xenograft (PDX) tumors and revealed 2 PDX clusters defined by protein networks associated with EGFR inhibitor resistance. In vivo validation revealed unbiased clustering to classify PDX tumors according to cetuximab response with 88% accuracy. Next, a support vector machine classifier algorithm identified a minimalist biomarker signature consisting of 8 proteins — caveolin-1, Sox-2, AXL, STING, Brd4, claudin-7, connexin-43, and fibronectin — with expression that strongly predicted cetuximab response in PDXs using either protein or mRNA. A combination of caveolin-1 and Sox-2 protein levels was sufficient to maintain high predictive accuracy, which we validated in tumor samples from patients with HNSCC with known clinical response to cetuximab. These results support further investigation into the combined use of caveolin-1 and Sox-2 as predictive biomarkers for cetuximab response in the clinic.
Mehdi Bouhaddou, Rex H. Lee, Hua Li, Neil E. Bhola, Rachel A. O’Keefe, Mohammad Naser, Tian Ran Zhu, Kelechi Nwachuku, Umamaheswar Duvvuri, Adam B. Olshen, Ritu Roy, Aaron Hechmer, Jennifer Bolen, Stephen B. Keysar, Antonio Jimeno, Gordon B. Mills, Scott Vandenberg, Danielle L. Swaney, Daniel E. Johnson, Nevan J. Krogan, Jennifer R. Grandis
The meager regenerative capacity of adult mammalian hearts appears to be driven by the proliferation of endogenous cardiomyocytes; thus, strategies targeting mechanisms of cardiomyocyte cell cycle regulation, such as the Hippo/Yes-associated protein (Hippo/Yap) pathway, could lead to the development of promising therapies for heart disease. The pharmacological product TT-10 increases cardiomyocyte proliferation by upregulating nuclear Yap levels. When intraperitoneal injections of TT-10 were administered to infarcted mouse hearts, the treatment promoted cardiomyocyte proliferation and was associated with declines in infarct size 1 week after administration, but cardiac function worsened at later time points. Here, we investigated whether encapsulating TT-10 into poly-lactic-co-glycolic acid nanoparticles (NPs) before administration could extend the duration of TT-10 delivery and improve the potency of TT-10 for myocardial repair. TT-10 was released from the TT-10–loaded NPs for up to 4 weeks in vitro, and intramyocardial injections of TT-10–delivered NPs stably improved cardiac function from week 1 to week 4 after administration to infarcted mouse hearts. TT-10–delivered NP treatment was also associated with significantly smaller infarcts at week 4, with increases in cardiomyocyte proliferation and nuclear Yap abundance and with declines in cardiomyocyte apoptosis. Thus, NP-mediated delivery appears to enhance both the potency and durability of TT-10 treatment for myocardial repair.
Knowledge of immune activation in the brain during acute HIV infection is crucial for the prevention and treatment of HIV-associated neurological disorders. We determined regional brain (basal ganglia, thalamus, and frontal cortex) immune and virological profiles at 7 and 14 days post infection (dpi) with SIVmac239 in rhesus macaques. The basal ganglia and thalamus had detectable viruses earlier (7 dpi) than the frontal cortex (14 dpi) and contained higher quantities of viruses than the latter. Increased immune activation of astrocytes and significant infiltration of macrophages in the thalamus at 14 dpi coincided with elevated plasma viral load, and SIV colocalized only within macrophages. RNA signatures of proinflammatory responses, including IL-6, were detected at 7 dpi in microglia and interestingly, preceded reliable detection of virus in tissues and were maintained in the chronically infected macaques. Countering the proinflammatory response, the antiinflammatory response was not detected until increased TGF-β expression was found in perivascular macrophages at 14 dpi. But this response was not detected in chronic infection. Our data provide evidence that the interplay of acute proinflammatory and antiinflammatory responses in the brain likely contributed to the overt neuroinflammation, where the immune activation preceded reliable viral detection.
Raja Mohan Gopalakrishnan, Malika Aid, Noe B. Mercado, Caitlin Davis, Shaily Malik, Emma Geiger, Valerie Varner, Rhianna Jones, Steven E. Bosinger, Cesar Piedra-Mora, Amanda J. Martinot, Dan H. Barouch, R. Keith Reeves, C. Sabrina Tan
In the COVID-19 pandemic, caused by SARS-CoV-2, many individuals experience prolonged symptoms, termed long-lasting COVID-19 symptoms (long COVID). Long COVID is thought to be linked to immune dysregulation due to harmful inflammation, with the exact causes being unknown. Given the role of the microbiome in mediating inflammation, we aimed to examine the relationship between the oral microbiome and the duration of long COVID symptoms. Tongue swabs were collected from patients presenting with COVID-19 symptoms. Confirmed infections were followed until resolution of all symptoms. Bacterial composition was determined by metagenomic sequencing. We used random forest modeling to identify microbiota and clinical covariates that are associated with long COVID symptoms. Of the patients followed, 63% developed ongoing symptomatic COVID-19 and 37% went on to long COVID. Patients with prolonged symptoms had significantly higher abundances of microbiota that induced inflammation, such as members of the genera Prevotella and Veillonella, which, of note, are species that produce LPS. The oral microbiome of patients with long COVID was similar to that of patients with chronic fatigue syndrome. Altogether, our findings suggest an association with the oral microbiome and long COVID, revealing the possibility that dysfunction of the oral microbiome may have contributed to this draining disease.
John P. Haran, Evan Bradley, Abigail L. Zeamer, Lindsey Cincotta, Marie-Claire Salive, Protiva Dutta, Shafik Mutaawe, Otuwe Anya, Mario Meza-Segura, Ann M. Moormann, Doyle V. Ward, Beth A. McCormick, Vanni Bucci
The PD-1/PD-L1 pathway is a key immune checkpoint that regulates T cell activation. There is strong rationale to develop PD-1 agonists as therapeutics against autoimmunity, but progress in this area has been limited. Here, we generated T cell receptor (TCR) targeting, PD-1 agonist bispecifics called ImmTAAI molecules that mimic the ability of PD-L1 to facilitate the colocalization of PD-1 with the TCR complex at the target cell–T cell interface. PD-1 agonist ImmTAAI molecules specifically bound to target cells and were highly effective in activating the PD-1 receptor on interacting T cells to achieve immune suppression. Potent PD-1 antibody ImmTAAI molecules closely mimicked the mechanism of action of endogenously expressed PD-L1 in their localization to the target cell–T cell interface, inhibition of proximal TCR signaling events, and suppression of T cell function. At picomolar concentrations, these bispecifics suppressed cytokine production and inhibited CD8+ T cell–mediated cytotoxicity in vitro. Crucially, in soluble form, the PD-1 ImmTAAI molecules were inactive and, hence, could avoid systemic immunosuppression. This study outlines a promising new route to generate more effective, potent, tissue-targeted PD-1 agonists that can inhibit T cell function locally with the potential to treat autoimmune and chronic inflammatory diseases of high unmet need.
Adam P. Curnock, Giovanna Bossi, Jyothi Kumaran, Lindsay J. Bawden, Rita Figueiredo, Rajeevkumar Tawar, Katherine Wiseman, Emma Henderson, Sec Julie Hoong, Veronica Gonzalez, Hemza Ghadbane, David E.O. Knight, Ronan O’Dwyer, David X. Overton, Christina M. Lucato, Nicola M.G. Smith, Carlos R. Reis, Keith Page, Lorraine M. Whaley, Michelle L. McCully, Stephen Hearty, Tara M. Mahon, Peter Weber
Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease associated with unremitting fibroblast activation including fibroblast-to-myofibroblast transformation (FMT), migration, resistance to apoptotic clearance, and excessive deposition of extracellular matrix (ECM) proteins in the distal lung parenchyma. Aberrant activation of lung-developmental pathways is associated with severe fibrotic lung disease; however, the mechanisms through which these pathways activate fibroblasts in IPF remain unclear. Sry-box transcription factor 9 (Sox9) is a member of the high-mobility group box family of DNA-binding transcription factors that are selectively expressed by epithelial cell progenitors to modulate branching morphogenesis during lung development. We demonstrate that Sox9 is upregulated via MAPK/PI3K-dependent signaling and by the transcription factor Wilms’ tumor 1 in distal lung-resident fibroblasts in IPF. Mechanistically, using fibroblast activation assays, we demonstrate that Sox9 functions as a positive regulator of FMT, migration, survival, and ECM production. Importantly, our in vivo studies demonstrate that fibroblast-specific deletion of Sox9 is sufficient to attenuate collagen deposition and improve lung function during TGF-α–induced pulmonary fibrosis. Using a mouse model of bleomycin-induced pulmonary fibrosis, we show that myofibroblast-specific Sox9 overexpression augments fibroblast activation and pulmonary fibrosis. Thus, Sox9 functions as a profibrotic transcription factor in activating fibroblasts, illustrating the potential utility of targeting Sox9 in IPF treatment.
Prathibha R. Gajjala, Rajesh K. Kasam, Divyalakshmi Soundararajan, Debora Sinner, Steven K. Huang, Anil G. Jegga, Satish K. Madala
Severe respiratory coronavirus 2 (SARS-CoV-2) promotes an imbalanced host response which underlies the development and severity of COVID-19. Infections with viruses are known to modulate transposable elements (TEs) which can exert downstream effects by modulating host gene expression, innate immune sensing, or activities encoded by their protein products. We investigated the impact of SARS-CoV-2 infection on TE expression using RNA-seq data from cell lines and from primary patient samples. Using a bioinformatic tool, Telescope, we showed that SARS-CoV-2 infection led to up- or down-regulation of TE transcripts, a subset of which differed from cells infected with SARS, MERS, RSV, HPIV3 or IAV. Differential expression of key retroelements specifically identified distinct virus families such as coronaviridae, with unique retroelement expression subdividing viral species. Analysis of ChIP-seq data shows that TEs differentially expressed in SARS-CoV-2 infection are enriched for binding sites for TFs involved in immune responses and for pioneer transcription factors. In COVID-19 patient samples, there was a significant TE overexpression in bronchoalveolar lavage fluid and downregulation in peripheral blood mononuclear cells. Thus, while the host gene transcriptome is altered by infection with SARS-CoV-2, the retrotranscriptome may contain the most distinctive features of the cellular response to SARS-CoV-2 infection.
Jez L. Marston, Matthew Greenig, Manvendra Singh, Matthew L. Bendall, Rodrigo R.R. Duarte, Cédric Feschotte, Luis P. Iñiguez, Douglas F. Nixon
Nociceptors, the high-threshold primary sensory neurons that trigger pain, interact with immune cells in the periphery to modulate innate immune responses. Whether they also participate in adaptive and humoral immunity is, however, not known. In this study, we probed if nociceptors have a role in distinct airway and skin models of allergic inflammation. In both models, the genetic ablation and pharmacological silencing of nociceptors substantially reduced inflammatory cell infiltration to the affected tissue. Moreover, we also found a profound and specific deficit in IgE production in these models of allergic inflammation. Mechanistically, we discovered that the nociceptor-released neuropeptide Substance P help triggered the formation of antibody secreting cells and their release of IgE. Our findings suggest that nociceptors, in addition to their contributions to innate immunity, play a key role in modulating the adaptive immune response, particularly B cell antibody class switching to IgE.
Shreya Mathur, Jo-Chiao Wang, Corey R. Seehus, Florence Poirier, Theo Crosson, Yu-Chen Hsieh, Benjamin Doyle, Seungkyu Lee, Clifford J. Woolf, Simmie L. Foster, Sebastien Talbot
Leukemia stem cells (LSCs) promote the disease and seem resistant to therapy and immune control. Why LSCs are selectively resistant against elimination by cytotoxic CD8+ T cells (CTLs) is still unknown. In this study, we demonstrate that LSCs in chronic myeloid leukemia (CML) can be recognized and killed by CD8+ CTLs in vitro. However, Tregs, which preferentially localized close to CD8+ CTLs in CML bone marrow (BM), protected LSCs from MHC-class I dependent CD8+ CTL-mediated elimination in vivo. BM Tregs in CML were characterized by the selective expression of tumor necrosis factor receptor 4 (Tnfrsf4). Stimulation of Tnfrsf4-signaling did not deplete Tregs but reduced the capacity of Tregs to protect LSCs from CD8+ CTL-mediated killing. In the BM of newly diagnosed CML patients, TNFRSF4 mRNA levels were significantly increased and correlated with the expression of the Treg-restricted transcription factor FOXP3. Overall, these results identify Tregs as key regulator of immune escape of LSCs and TNFRSF4 as a potential target to reduce the function of Tregs and boost anti-leukemic immunity in CML.
Magdalena Hinterbrandner, Viviana Rubino, Carina Stoll, Stefan Forster, Noah Schnüriger, Ramin Radpour, Gabriela M. Baerlocher, Adrian F. Ochsenbein, Carsten Riether
Osteoarthritis is the most prevalent joint disease worldwide and a leading source of pain and disability. To date, this disease lacks curative treatment as underlying molecular mechanisms remain largely unknown. The histone methyltransferase DOT1L protects against osteoarthritis, and DOT1L-mediated H3K79 methylation is reduced in human and mouse osteoarthritic joints. Thus, restoring DOT1L function seems to be critical to preserve joint health. However, DOT1L-regulating molecules and networks remain elusive, in the joint and beyond. Here, we identify transcription factors and networks that regulate DOT1L gene expression using a novel bioinformatics pipeline. Thereby, we unravel an undiscovered link between the hypoxia pathway and DOT1L. We provide unprecedented evidence that hypoxia enhances DOT1L expression and H3K79 methylation via Hypoxia-inducible factor-1 alpha (HIF1A). Importantly, we demonstrate that DOT1L contributes to the protective effects of hypoxia in articular cartilage and osteoarthritis. Intra-articular treatment with a selective hypoxia mimetic in mice after surgical induction of osteoarthritis restores DOT1L function and stalls disease progression. Collectively, our data unravel a novel molecular mechanism that protects against osteoarthritis with hypoxia inducing DOT1L transcription in cartilage. Local treatment with a selective hypoxia mimetic in the joint restores DOT1L function and could be an attractive therapeutic strategy for osteoarthritis.
Astrid De Roover, Ana Escribano Núñez, Frederique M.F. Cornelis, Chahrazad Cherifi, Leire Casas-Fraile, An Sermon, Frederic Cailotto, Rik J. Lories, Silvia Monteagudo
Bacterial cancer therapy (BCT) shows great promise for treatment of solid tumors, yet basic mechanisms of bacterial-induced tumor suppression remain undefined. Attenuated strains of Salmonella enterica serovar Typhimurium (STm) have commonly been used in mouse models of BCT in xenograft and orthotopic transplant cancer models. We aimed to better understand the tumor epithelium-targeted mechanisms of BCT by using autochthonous mouse models of intestinal cancer and tumor organoid cultures to assess the effectiveness and consequences of oral treatment with aromatase A-deficient STm (STm∆aroA). STm∆aroA delivered by oral gavage significantly reduced tumor burden and tumor load in both a colitis-associated colon cancer model (CAC) and in a spontaneous Apcmin/+ intestinal cancer model. STm∆aroA colonization of tumors caused alterations in transcription of mRNAs associated with tumor stemness, epithelial–mesenchymal transition and cell cycle. Metabolomic analysis of tumors demonstrated alteration in the metabolic environment of STm∆aroA-treated tumors, suggesting STm∆aroA imposes metabolic competition on the tumor. Use of tumor organoid cultures in vitro recapitulated effects seen on tumor stemness, mesenchymal markers and altered metabolome. Furthermore, live STm∆aroA was required, demonstrating active mechanisms including metabolite usage. We demonstrate that BCT is efficacious in autochthonous intestinal cancer models, that BCT imposes metabolic competition, and that BCT has direct effects on the tumor epithelium affecting tumor stem cells.