Apolipoprotein L1 (APOL1) risk-alleles in donor kidneys associate with graft loss but whether recipient risk-allele expression impacts transplant outcomes is unclear. To test whether recipient APOL1 risk-alleles independently correlate with transplant outcomes, we analyzed genome-wide SNP genotyping data of donors and recipients from two kidney transplant cohorts, Genomics of Chronic Allograft Rejection (GOCAR) and Clinical Trials in Organ Transplantation (CTOT1/17). We estimated genetic ancestry (quantified as proportion of African ancestry or pAFR) by ADMIXTURE and correlated APOL1 genotypes and pAFR with outcomes. In the GOCAR discovery set, we observed that the number of recipient APOL1 G1/G2 alleles (R-nAPOL1) associated with increased risk of death-censored allograft loss (DCAL), independent of ancestry (HR = 2.14; P = 0.006), and within the subgroup of African American and Hispanic (AA/H) recipients (HR = 2.36; P = 0.003). R-nAPOL1 also associated with increased risk of any T cell-mediated rejection (TCMR) event. These associations were validated in CTOT1/17. Ex vivo studies of peripheral blood mononuclear cells revealed unanticipated high APOL1 expression in activated CD4+/CD8+ T cells and natural killer cells. We detected enriched immune response gene pathways in risk-allele carriers vs. non-carriers on the kidney transplant waitlist and among healthy controls. Our findings demonstrate an immunomodulatory role for recipient APOL1 risk-alleles associating with TCMR and DCAL. This finding has broader implications for immune mediated injury to native kidneys.
Zhongyang Zhang, Zeguo Sun, Jia Fu, Qisheng Lin, Khadija Banu, Kinsuk Chauhan, Marina Planoutene, Chengguo Wei, Fadi Salem, Zhengzi Yi, Ruijie Liu, Paolo Cravedi, Haoxiang Cheng, Ke Hao, Philip J. O’Connell, Shuta Ishibe, Weijia Zhang, Steven G. Coca, Ian W. Gibson, Robert B. Colvin, John C. He, Peter S. Heeger, Barbara T. Murphy, Madhav C. Menon
The endocannabinoid system regulates appetite and energy expenditure and inhibitors of the cannabinoid receptor-1 (CB-1) induce weight loss with improvement in components of the metabolic syndrome. While CB-1 blockage in brain is responsible for weight loss, many of the metabolic benefits associated with CB-1 blockade have been attributed to inhibition of CB-1 signaling in the periphery. As a result, there has been interest in developing a peripherally restricted CB-1 inhibitor for the treatment of nonalcoholic fatty liver disease (NAFLD) that would lack the unwanted centrally mediated side effects. Here, we produced mice that lacked CB-1 receptors in hepatocytes or stellate cells to determine if CB-1 signaling contributes to the development of NAFLD or liver fibrosis. Deletion of CB-1 receptors in hepatocytes did not alter the development of NAFLD in mice fed a high sucrose high fat diet or high fat diet (HFD). Similarly, deletion of CB-1 deletion specifically in stellate cells also did not prevent the development of NAFLD in mice fed the HFD nor did it protect mice for carbon tetrachloride (CCl4)-induced fibrosis. Combined, these studies do not support a direct role for hepatocyte or stellate cell CB-1 signaling in the development of NAFLD or liver fibrosis.
Simeng Wang, Qingzhang Zhu, Guosheng Liang, Tania Franks, Magalie Boucher, Kendra K. Bence, Mingjian Lu, Carlos M. Castorena, Shangang Zhao, Joel K. Elmquist, Philipp E. Scherer, Jay D. Horton
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19). Little is known about the interplay between pre-existing immunity towards endemic seasonal coronaviruses and the development of a SARS-CoV-2-specific IgG response. We investigated the kinetics, breadth, magnitude and level of cross-reactivity of IgG antibodies against SARS-CoV-2 and heterologous seasonal and epidemic coronaviruses at the clonal level in mild and severe COVID-19 patients and disease control patients. Antibody reactivity towards nucleocapsid and spike antigens was assessed and correlated to SARS-CoV-2 neutralization. COVID-19 patients mounted a mostly type-specific SARS-CoV-2 response. Additionally, IgG clones directed against seasonal coronavirus were boosted in patients with severe COVID-19. These boosted clones showed limited cross-reactivity and did not neutralize SARS-CoV-2. These findings support a boost of poorly protective coronavirus-specific antibodies in COVID-19 patients that correlates with disease severity, revealing original antigenic sin.
Muriel Aguilar-Bretones, Brenda M. Westerhuis, Matthijs P. Raadsen, Erwin de Bruin, Felicity D. Chandler, Nisreen M.A. Okba, Bart L. Haagmans, Thomas Langerak, Henrik Endeman, Johannes P.C. van den Akker, Diederik A.M.P.J. Gommers, Eric C.M. van Gorp, Corine H. GeurtsvanKessel, Rory D. de Vries, Ron A.M. Fouchier, Barry H.G. Rockx, Marion P.G. Koopmans, Gijsbert P. van Nierop
Loss-of-function mutations in the transcription factor CREB3L3 (CREBH) associate with severe hypertriglyceridemia in humans. CREBH is believed to lower plasma triglycerides by augmenting the action of lipoprotein lipase (LPL). However, by using a mouse model of type 1 diabetes mellitus (T1DM), we found that greater liver expression of active CREBH normalized both elevated plasma triglycerides and cholesterol. Residual triglyceride-rich lipoprotein (TRL) remnants were enriched in apolipoprotein E (APOE) and impoverished in APOC3, an apolipoprotein composition indicative of increased hepatic clearance. The underlying mechanism was independent of LPL as CREBH reduced both triglycerides and cholesterol in LPL-deficient mice. Instead, APOE was critical for CREBH’s ability to lower circulating remnant lipoproteins because it failed to reduce TRL cholesterol in Apoe-/- mice. Importantly, humans with CREB3L3 loss-of-function mutations exhibited increased levels of remnant lipoproteins that were deprived of APOE. Recent evidence suggests that impaired clearance of TRL remnants promotes cardiovascular disease in patients with T1DM. Consistently, we found that hepatic expression of CREBH prevented the progression of diabetes-accelerated atherosclerosis. Our results support the proposal that CREBH acts through an APOE-dependent pathway to increase hepatic clearance of remnant lipoproteins. They also implicate elevated levels of remnants in the pathogenesis of atherosclerosis in T1DM.
Masami Shimizu-Albergine, Debapriya Basu, Jenny E. Kanter, Farah Kramer, Vishal Kothari, Shelley Barnhart, Carissa Thornock, Adam E. Mullick, Noemie Clouet-Foraison, Tomas Vaisar, Jay W. Heinecke, Robert A. Hegele, Ira J. Goldberg, Karin E. Bornfeldt
The transcription factor NFATC2 induces β-cell proliferation in mouse and human islets. However, the genomic targets that mediate these effects have not been identified. We expressed active forms of Nfatc2 and Nfatc1 in human islets. By integrating changes in gene expression with genomic binding sites for NFATC2, we identified ~2,200 transcriptional targets of NFATC2. Genes induced by NFATC2 were enriched for transcripts that regulate the cell cycle, and for DNA motifs associated with the transcription factor FOXP. Islets from an endocrine-specific Foxp1, Foxp2, and Foxp4 triple-knockout mouse are less responsive to NFATC2-induced β-cell proliferation, suggesting the FOXP family works to regulate β-cell proliferation in concert with NFATC2. NFATC2 induced β-cell proliferation in both mouse and human islets, whereas NFATC1 did so only in human islets. Exploiting this species difference, we identified ~250 direct transcriptional targets of NFAT in human islets. This gene set enriches for cell cycle-associated transcripts, and includes Nr4a1. Deletion of Nr4a1 reduced the capacity of NFATC2 to induce β-cell proliferation, suggesting that much of the effect of NFATC2 occurs through its induction of Nr4a1. Integration of non-coding RNA expression, chromatin accessibility, and NFATC2 binding sites enabled us to identify NFATC2-dependent enhancer loci that mediate β-cell proliferation.
Shane P. Simonett, Sunyoung Shin, Jacob A. Herring, Rhonda Bacher, Linsin A. Smith, Chenyang Dong, Mary E. Rabaglia, Donnie S. Stapleton, Kathryn L. Schueler, Jeea Choi, Matthew N. Bernstein, Daniel R. Turkewitz, Carlos Perez-Cervantes, Jason Spaeth, Roland Stein, Jeffery S. Tessem, Christina Kendziorski, Sunduz Keles, Ivan P. Moskowitz, Mark P. Keller, Alan D. Attie
Initiation of T cell receptor (TCR) signaling involves the activation of the tyrosine kinase LCK; however, it is currently unclear how LCK is recruited and activated. Here, we have identified the membrane protein CD146 as an essential member of the TCR network for LCK activation. CD146 deficiency in T cells substantially impaired thymocyte development and peripheral activation, both of which depend on TCR signaling. CD146 was found to directly interact with the SH3 domain of coreceptor-free LCK via its cytoplasmic domain. Interestingly, CD146 was found to be present in both monomeric and dimeric forms in T cells, with the dimerized form increasing after TCR ligation. Increased dimerized CD146 recruited LCK and promoted LCK autophosphorylation. In tumor models, CD146 deficiency dramatically impaired the anti-tumor response of T cells. Together, our data reveal a previously unrecognized LCK activation mechanism for TCR initiation. We also underscore a rational intervention based on CD146 for tumor immunotherapy.
Hongxia Duan, Lin Jing, Xiaoqing Jiang, Yanbin Ma, Daji Wang, Jianquan Xiang, Xuehui Chen, Zhenzhen Wu, Huiwen Yan, Junying Jia, Zheng Liu, Jing Feng, Mingzhao Zhu, Xiyun Yan
Peripheral nerves have the capacity for regeneration, but the rate of regeneration is so slow that many nerve injuries lead to incomplete recovery and permanent disability for patients. Macrophages play a critical role in the peripheral nerve response to injury, both for Wallerian degeneration and for contributing to regeneration, and their function has recently been shown to be dependent on intracellular metabolism. To date, the impact of their intracellular metabolism on peripheral nerve regeneration has not been studied. Examining conditional transgenic mice with selective ablation of solute carrier family 16, member 1 (Slc16a1, which encodes the monocarboxylate transporter 1, MCT1) in macrophages, we found that MCT1 contributes to macrophage metabolism, phenotype, and function, specifically in regard to phagocytosis and supporting peripheral nerve regeneration. Adoptive cell transfer of wild-type macrophages ameliorated the impaired nerve regeneration in macrophage-selective MCT1 null mice. We also developed a mouse model that overexpresses MCT1 in macrophages and found that peripheral nerves in these mice regenerated more rapidly than control mice. Our study provides further evidence that MCT1 has an important biological role in macrophages and that manipulations of macrophage metabolism can enhance recovery from peripheral nerve injuries, for which there are currently no approved medical therapies.
Mithilesh Kumar Jha, Joseph V. Passero, Atul Rawat, Xanthe Heifetz Ament, Fang Yang, Svetlana Vidensky, Samuel L. Collins, Maureen R. Horton, Ahmet Hoke, Guy A. Rutter, Alban Latremoliere, Jeffrey D. Rothstein, Brett M. Morrison
Spreading depolarizations (SDs) are involved in migraine, epilepsy, stroke, traumatic brain injury, and subarachnoid haemorrhage. However, the cellular origin and specific differential mechanisms are not clear yet. Increased glutamatergic activity is thought to be the key factor for generating cortical spreading depression (CSD), a pathological mechanism of migraine. Here, we show that acute pharmacological activation of NaV1.1 (the main Na+ channel of interneurons) or optogenetic-induced hyperactivity of GABAergic interneurons is sufficient to ignite CSD in the neocortex by spiking-generated extracellular K+ build-up. Neither GABAergic nor glutamatergic synaptic transmission were required for CSD initiation. CSD was not generated in other brain areas, suggesting that this is a neocortex-specific mechanism of CSD initiation. Gain-of-function mutations of NaV1.1 (SCN1A) cause Familial Hemiplegic Migraine type-3 (FHM3), a subtype of migraine with aura, of which CSD is the neurophysiological correlate. Our results provide the mechanism linking NaV1.1 gain-of-function to CSD generation in FHM3. Thus, we reveal the key role of hyperactivity of GABAergic interneurons in a mechanism of CSD initiation, which is relevant as pathological mechanism of Nav1.1 FHM3 mutations, and possibly also for other types of migraine and diseases in which SDs are involved.
Oana Chever, Sarah Zerimech, Paolo Scalmani, Louisiane Lemaire, Lara Pizzamiglio, Alexandre Loucif, Marion Ayrault, Martin Krupa, Mathieu Desroches, Fabrice Duprat, Isabelle Léna, Sandrine Cestèle, Massimo Mantegazza
Persons living with HIV (PLWH) are at increased risk of tuberculosis (TB). HIV-associated TB is often the result of recent infection with Mycobacterium tuberculosis (Mtb) followed by rapid progression to disease. Alveolar macrophages (AM) are the first cells of the innate immune system that engage Mtb, but how HIV and antiretroviral therapy (ART) impact on the anti-mycobacterial response of AM is not known. To investigate the impact of HIV and ART on the transcriptomic and epigenetic response of AM to Mtb, we obtained AM by bronchoalveolar lavage from 20 PLWH receiving ART, 16 control subjects who were HIV-free (HC), and 14 subjects who received ART as pre-exposure prophylaxis (PrEP) to prevent HIV infection. Following in-vitro challenge with Mtb, AM from each group displayed overlapping but distinct profiles of significantly up- and down-regulated genes in response to Mtb. Comparatively, AM isolated from both PLWH and PrEP subjects presented a substantially weaker transcriptional response. In addition, AM from HC subjects challenged with Mtb responded with pronounced chromatin accessibility changes while AM obtained from PLWH and PrEP subjects displayed no significant changes in their chromatin state. Collectively, these results revealed a stronger adverse effect of ART than HIV on the epigenetic landscape and transcriptional responsiveness of AM.
Wilian Correa-Macedo, Vinicius M. Fava, Marianna Orlova, Pauline Cassart, Ron Olivenstein, Joaquín Sanz, Yong Zhong Xu, Anne Dumaine, Renata H.M. Sindeaux, Vania Yotova, Alain Pacis, Josée Girouard, Barbara Kalsdorf, Christoph Lange, Jean-Pierre Routy, Luis B. Barreiro, Erwin Schurr
BACKGROUND. Primary polydipsia, characterized by excessive fluid intake, carries the risk of water intoxication and hyponatremia, but treatment options are scarce. Glucagon-like peptide-1 (GLP-1) reduces appetite and food intake. In experimental models, they also play a role in thirst and drinking behavior. The aim of this trial was to investigate whether GLP-1 receptor agonists reduce fluid intake in patients with primary polydipsia. METHODS. In this randomized, double-blind, placebo-controlled, 3-week crossover-trial, 34 patients with primary polydipsia received weekly dulaglutide (Trulicity®) 1.5mg and placebo (0.9% sodium chloride). During the last treatment week, patients attended an 8-hour evaluation visit with free water access. The primary endpoint was total fluid intake during the evaluation visits. Treatment effects were estimated using linear mixed-effects models. In a subset of 15 patients and additional 15 matched controls, thirst perception and neuronal activity in response to beverage pictures were assessed by functional MRI. FINDINGS. Patients on dulaglutide reduced fluid intake by 490ml [95%-CI -780, -199], p=0.002, from 2950ml [95% CI 2435, 3465] on placebo to 2460ml [95% CI 1946, 2475] on dulaglutide (model estimates), corresponding to a relative reduction of 17%. 24-hour urinary output was reduced by -943ml [95%-CI -1473, -413], p=0.001. Thirst perception in response to beverage pictures was higher in patients with primary polydipsia versus controls and lower on dulaglutide versus placebo, but functional activity was similar between groups and treatments. INTERPRETATION. GLP-1 receptor agonists reduce fluid intake and thirst perception in patients with primary polydipsia and could therefore be a treatment option for these patients.
Bettina Winzeler, Clara Odilia Sailer, David Coynel, Davide Zanchi, Deborah R. Vogt, Sandrine Andrea Urwyler, Julie Refardt, Mirjam Christ-Crain
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