BACKGROUND. Identifying patients with acute kidney injury (AKI) who are at higher risk of chronic kidney disease (CKD) progression at time of AKI diagnosis remains a major challenge in clinical practice. METHODS. Kidney transcriptome sequencing was applied to identify the top up-regulated genes in mice with AKI. The product of the top-ranked gene was identified in the tubular cells and urine both in mouse and human AKI. Data from two cohorts of patients with a prehospitalization estimated glomerular filtration rate (eGFR) ≥ 45 ml/min/1.73m2 who survived for at least 90 days after AKI were used to derive and validate multivariable prediction models. AKI to CKD progression was defined as a persistent eGFR < 60 ml/min/1.73m2 and with a minimum 25% reduction from baseline eGFR 90 days after AKI in patients with prehospitalization eGFR ≥ 60 ml/min/1.73m2. AKI to advanced CKD was defined by a sustained reduction of eGFR < 30 ml/min/1.73m2 90 days after AKI in those with prehospitalization eGFR 45–60 ml/min/1.73m2. RESULTS. Kidney cytokeratin 20 (CK20) was up-regulated in injured proximal tubular cells and detectable in urine within 7 days after AKI. High concentrations of urinary CK20 (uCK20) were independently associated with the severity of histological AKI and the risk of AKI to CKD or advanced CKD progression. In Test set, the AUC of uCK20 for predicting AKI to CKD or advanced CKD was 0.80, outperformed currently used biomarkers for detecting kidney tubular injury. Addition of uCK20 to an established clinical model improved the ability for predicting AKI-CKD progression with an AUC of 0.90, and largely improved the risk reclassification. CONCLUSION. This finding highlighted uCK20 as a useful predictor for AKI to CKD progression, and may provide a tool to early identify patients at high risk of CKD following AKI. FUNDING. The National Natural Science Foundation of China (Key Program).
Rui Ma, Han Ouyang, Shihong Meng, Jun Liu, Jianwei Tian, Nan Jia, Youhua Liu, Xin Xu, Xiaobing Yang, Fan Fan Hou
Tumor evolution is driven by genetic variation; however, it is the tumor microenvironment (TME) that provides the selective pressure contributing to evolution in cancer. Despite high histopathological heterogeneity within glioblastoma (GBM), the most aggressive brain tumor, the interactions between the genetically distinct GBM cells and the surrounding TME are not fully understood. To address this, we analyzed matched primary and recurrent GBM archival tumor tissues with imaging-based techniques aimed to simultaneously evaluate tumor tissues for presence of hypoxic, angiogenic, and inflammatory niches, extracellular matrix organization, TERT promoter mutational status, and several oncogenic amplifications on the same slide and location. We found that the relationships between genetic and TME diversity are different in primary and matched recurrent tumors. Interestingly, the texture of the extracellular matrix (ECM), identified by label-free reflectance imaging, was predictive of single-cell genetic traits present in the tissue. Moreover, reflectance of ECM revealed structured organization of the perivascular niche in recurrent GBM, enriched in immunosuppressive macrophages. Single-cell spatial transcriptomics further confirmed the presence of the niche-specific macrophage populations and identified interactions between endothelial cells, perivascular fibroblasts, and immunosuppressive macrophages. Our results underscore the importance of GBM tissue organization in tumor evolution and highlight novel genetic and spatial dependencies.
Ugoma Onubogu, Chandler D. Gatenbee, Sandhya Prabhakaran, Kelsey Wolfe, Benjamin Oakes, Roberto Salatino, Rachael Vaubel, Oszkar Szentirmai, Alexander R. A. Anderson, Michalina Janiszewska
Prenatal exposure to viral pathogens has been known to cause the development of neuropsychiatric disorders in adulthood. Furthermore, COVID-19 has been associated with a variety of neurological manifestations, raising the question of whether in utero SARS-CoV-2 exposure can affect neurodevelopment, resulting in long-lasting behavioral and cognitive deficits. Using a human ACE-2-knock-in mouse model, we have previously shown that prenatal exposure to SARS-CoV-2 at later stages of development leads to fetal brain infection and gliosis in the hippocampus and cortex. In this study, we aimed to determine if infection of the fetal brain results in long-term neuroanatomical alterations of the cortex and hippocampus, as well as any cognitive deficits in adulthood. Here, we show that infected mice developed slower and weighed less in adulthood. We also found altered hippocampal and amygdala volume and aberrant newborn neuron morphology in the hippocampus of adult mice infected in utero. Furthermore, we observed sex-dependent alterations in anxiety-like behavior and locomotion, as well as hippocampal-dependent spatial memory. Taken together, our study revealed long-lasting neurological and cognitive changes as a result of prenatal SARS-CoV-2 infection, identifying a window for early intervention and highlighting the importance of immunization and antiviral intervention in pregnant women.
Courtney L. McMahon, Erin M. Hurley, Aranis Muniz Perez, Manuel Estrada, Daniel J. Lodge, Jenny Hsieh
We present a transcriptomic analysis that provides a better understanding of regulatory mechanisms within the healthy and injured periosteum. The focus of this work is on characterizing early events controlling bone healing during formation of periosteal callus on day 3 post fracture. Building upon our previous findings showing that induced Notch1 signaling in osteoprogenitors leads to better healing, we compared samples in which Notch 1 intracellular domain is overexpressed by periosteal stem/progenitor cells with control intact and fractured periosteum. Molecular mechanisms and changes in skeletal stem/progenitor cells (SSPCs) and other cell populations within the callus, including hematopoietic lineages were determined. Notably, Notch ligands were differentially expressed in endothelial and mesenchymal populations, with Dll4 restricted to endothelial cells, whereas Jag1 was expressed by mesenchymal populations. Targeted deletion of Dll4 in endothelial cells using Cdh5CreER resulted in negative effects on early fracture healing, while deletion in SSPCs using α-smooth muscle actin-CreER did not impact bone healing. Translating these observations into clinically relevant model of bone healing revealed the beneficial effects of delivering Notch ligands alongside osteogenic inducer, BMP2. These findings provide insights into the regulatory mechanisms within the healthy and injured periosteum, paving the way for novel translational approaches to bone healing.
Sanja Novak, Hitoshi Tanigawa, Vijender Singh, Sierra H. Root, Tannin A. Schmidt, Kurt D. Hankenson, Ivo Kalajzic
Dendritic cell inhibitory receptor (DCIR) is a C-type lectin receptor selectively expressed on myeloid cells, including monocytes, macrophage, dendritic cells, and neutrophils. Its role in immune regulation has been implicated in murine models and human genome-wide association studies (GWAS), suggesting defective DCIR function associates with increased susceptibility to autoimmune diseases such as rheumatoid arthritis, lupus and Sjogren’s syndrome. However, little is known about the mechanisms underlying DCIR activation to dampen inflammation. Here, we developed anti-DCIR agonistic antibodies that promote phosphorylation on DCIR’s immune receptor tyrosine-based inhibitory motifs (ITIM) and recruitment of SH2 containing protein tyrosine phosphatase-2 (SHP2) for reducing inflammation. We also explored the inflammation resolution by depleting DCIR+ cells with antibodies. Utilizing a human DCIR knock-in mouse model, we validated the anti-inflammatory properties of the agonistic anti-DCIR antibody in experimental peritonitis and colitis. These findings provide critical evidence for targeting DCIR to develop transformative therapies for inflammatory diseases.
Liang Chen, Suresh Patil, Jeffrey Barbon, James Waire, F. Stephen Laroux, Donna McCarthy, Mishra Pratibha, Suju Zhong, Feng Dong, Karin Orsi, Gunarso Nguyen, Yingli Yang, Nancy Crosbie, Eric Dominguez, Arun Deora, Geertruida Veldman, Susan V. Westmoreland, Liang Jin, Timothy Radstake, Kevin White, Hsi-Ju Wei
The mechanisms responsible for the distribution and severity of joint involvement in rheumatoid arthritis (RA) are not known. To explore whether site-specific FLS biology might be associated with location-specific synovitis and explain the predilection for hand (wrist/metacarpal phalangeal joints) involvement in RA, we generated transcriptomic and chromatin accessibility data from FLS to identify the transcription factors (TFs) and pathways. Networks were constructed by integration of chromatin accessibility and gene expression data. Analysis revealed joint-specific patterns of FLS phenotype, with proliferative, migratory, proinflammatory, and matrix-degrading characteristics observed in resting FLS derived from the hand joints compared with hip or knee. TNF-stimulation amplified these differences, with greater enrichment of proinflammatory and proliferative genes in hand FLS compared with hip and knee FLS. Hand FLS also had the greatest expression of markers associated with an ‘activated’ state relative to the ‘resting’ state, with the greatest cytokine and MMP expression in TNF-stimulated hand FLS. Predicted differences in proliferation and migration were biologically validated with hand FLS exhibiting greater migration and cell growth than hip or knee FLS. Distinctive joint-specific FLS biology associated with a more aggressive inflammatory response might contribute to the distribution and severity of joint involvement in RA.
Eunice Choi, Camilla R. L. Machado, Takaichi Okano, David L. Boyle, Wei Wang, Gary S. Firestein
The most common subtype of lymphoma globally, diffuse large B-cell lymphoma (DLBCL) is a leading cause of cancer death in people with HIV (HIV+). The restructuring of the T-cell compartment due to HIV infection and antiretroviral therapy (ART) may have implications for modern treatment selection, but current understanding of these dynamic interactions is limited. Here, we investigated the T-cell response to DLBCL by sequencing the T-cell receptor (TCR) repertoire in a cohort of HIV-negative (HIV-), HIV+/ART-experienced and HIV+/ART-naïve DLBCL patients. HIV+/ART-naïve tumor TCR repertoires were more clonal and more distinct from each other than HIV- and HIV+/ART-experienced. Further, increased overlap between tumor and blood TCR repertoires was associated with improved survival and HIV/ART status. Our study describes TCR repertoire characteristics for the first time in an African DLBCL cohort and demonstrates contributions of HIV infection and ART exposure to the DLBCL TCR repertoire.
Sophia M. Roush, Jenny Coelho, Alexander M. Xu, Kaushik Puranam, Marriam Mponda, Edwards Kasonkanji, Maurice Mulenga, Tamiwe Tomoka, Jonathan Galeotti, Amy Brownlee, Hormas Ghadially, Maganizo Chagomerana, Blossom Damania, Matthew Painschab, Akil Merchant, Satish Gopal, Yuri Fedoriw
Immunosuppression is a common feature of esophageal adenocarcinoma (EAC) and has been linked to poor overall survival (OS). We hypothesized that upstream factors might negatively influence CD3 levels and T-cell activity, thus promoting immunosuppression and worse survival. We used clinical data and patient samples of those who progressed from Barrett’s (BE) to dysplasia to EAC, investigated gene (RNAseq), protein (tissue microarray) expression and performed cell biology studies to delineate a pathway impacting CD3 protein stability that might influence EAC outcome. We show that the loss of both CD3-ε expression and CD3+ T-cell number are correlated with worse OS in EAC. The GRAIL (gene related to anergy in lymphocytes) isoform 1 (GRAIL1), which is the prominent isoform in EACs, degrades (ε, γ, δ) CD3s and inactivates T-cells. In contrast, isoform 2 (GRAIL2), which is reduced in EACs, stabilizes CD3s. Further, GRAIL1 mediated CD3 degradation is facilitated by interferon stimulated gene 15 (ISG15), a ubiquitin-like protein. Consequently, either the overexpression of a ligase-dead GRAIL1, ISG15 knockdown, or the overexpression of a conjugation-defective ISG15-LRAA mutant can increase CD3 levels. Together, we identified that an ISG15→GRAIL1→mutant p53 amplification loop negatively influencing CD3 levels and T-cell activity, thus promoting immunosuppression in EAC.
Dyke P. McEwen, Paramita Ray, Derek J. Nancarrow, Zhuwen Wang, Srimathi Kasturirangan, Saeed Abdullah, Ayushi Balan, Rishi Hoskeri, Dafydd Thomas, Theodore S. Lawrence, David G. Beer, Kiran H. Lagisetty, Dipankar Ray
Acute Pancreatitis (AP) is among the most common hospital gastrointestinal diagnosis; understanding the mechanisms underlying the severity of AP are critical for development of new treatment options for this disease. Here, we evaluate the biological function of phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in AP pathogenesis in two independent genetically engineered mouse models of AP. PFKFB3 is elevated in AP and severe AP (SAP) and knockout of Pfkfb3 abrogates the severity of alcoholic SAP (FAEE-SAP). Using a combination of genetic, pharmacological, and molecular studies we define the interaction of PFKFB3 with inositol 1,4,5-trisphosphate receptor (IP3R) as a key event mediating this phenomenon. Further analysis demonstrated that the interaction between PFKFB3 and IP3R promotes FAEE-SAP severity by altering intracellular calcium homeostasis in acinar cells. Together our results support a PFKFB3-driven mechanism controlling AP pathobiology and define this enzyme as a therapeutic target to ameliorate the severity of this dismal condition.
Tan Zhang, Shengchuan Chen, Liang Li, Yuepeng Jin, Siying Liu, Zhu Liu, Fengyu Shi, Lifen Xie, Panpan Guo, Andrew C. Cannon, Akmal Ergashev, Haiping Yao, Chaohao Huang, Baofu Zhang, Lijun Wu, Hongwei Sun, Siming Chen, Yunfeng Shan, Zhengping Yu, Ezequiel J. Tolosa, Jianghuai Liu, Martin E. Fernandez-Zapico, Feng Ma, Gang Chen
Caloric restriction improves metabolic health, but is often complicated by bone loss. We studied bone parameters in humans during a 10-day fast and identified candidate metabolic regulators of bone turnover. P1NP, a bone formation marker, decreased within 3 days of fasting. Whereas dual-energy X-ray absorptiometry measures of bone mineral density were unchanged after 10 days of fasting, high-resolution peripheral quantitative CT demonstrated remodeling of bone microarchitecture. Pathway analysis of longitudinal metabolomics data identified one-carbon metabolism as fasting-dependent. In cultured osteoblasts, we tested the functional significance of one-carbon metabolites modulated by fasting, finding that methionine — which surged after 3 days of fasting — impacted markers of osteoblast cell state in a concentration dependent manner, in some instances exhibiting a U-shaped response with both low and high concentrations driving putative anti-bone responses. Administration of methionine to mice for 5 days recapitulated some fasting effects on bone, including a reduction in serum P1NP. In conclusion, a 10-day fast in humans led to remodeling of bone microarchitecture, potentially mediated by a surge in circulating methionine. These data support an emerging model that points to a window of optimal methionine exposure for bone health.
Tânia Amorim, Naveen G.V. Kumar, Natalie L. David, William Dion, Trishya Pagadala, Nandini K. Doshi, Bokai Zhu, Andrey Parkhitko, Matthew L. Steinhauser, Pouneh K. Fazeli
Pathogenic variants in SCN8A, which encodes the voltage-gated sodium (NaV) channel NaV1.6, associate with neurodevelopmental disorders including developmental and epileptic encephalopathy. Previous approaches to determine SCN8A variant function may be confounded by use of a neonatal-expressed alternatively spliced isoform of NaV1.6 (NaV1.6N), and engineered mutations rendering the channel tetrodotoxin (TTX) resistant. We investigated the impact of SCN8A alternative splicing on variant function by comparing the functional attributes of 15 variants expressed in two developmentally regulated splice isoforms (NaV1.6N, NaV1.6A). We employed automated patch clamp recording to enhance throughput, and developed a novel neuronal cell line (ND7/LoNav) with low levels of endogenous NaV current to obviate the need for TTX-resistance mutations. Expression of NaV1.6N or NaV1.6A in ND7/LoNav cells generated NaV currents with small but significant differences in voltage-dependence of activation and inactivation. TTX-resistant versions of both isoforms exhibited significant functional differences compared to the corresponding wild-type (WT) channels. We demonstrated that many of the 15 disease-associated variants studied exhibited isoform-dependent functional effects, and that many of the studied SCN8A variants exhibited functional properties that were not easily classified as either gain- or loss-of-function. Our work illustrated the value of considering molecular and cellular context when investigating SCN8A variants.
Carlos G. Vanoye, Tatiana V. Abramova, Jean-Marc Dekeyser, Nora F. Ghabra, Madeleine J. Oudin, Christopher B. Burge, Ingo Helbig, Christopher H. Thompson, Alfred L. George Jr.
Hypotrichosis is a genetic disorder which characterized by a diffuse and progressive loss of scalp and/or body hair. Nonetheless, the causative genes for several affected individuals remain elusive, and the underlying mechanisms have yet to be fully elucidated. Here, we discovered a dominant variant in ADAM17 gene caused hypotrichosis with woolly hair. Adam17 (p.D647N) knock-in mice model mimicked the hair abnormality in patients. ADAM17 (p.D647N) mutation led to hair follicle stem cells (HFSCs) exhaustion and caused abnormal hair follicles, ultimately resulting in alopecia. Mechanistic studies revealed that ADAM17 binds directly to E3 ubiquitin ligase TRIM47. ADAM17 (p.D647N) variant enhanced the association between ADAM17 and TRIM47, leading to an increase in ubiquitination and subsequent degradation of ADAM17 protein. Furthermore, reduced ADAM17 protein expression affected Notch signaling pathway, impairing the activation, proliferation, and differentiation of HFSCs during hair follicle regeneration. Overexpression of NICD rescued the reduced proliferation ability caused by Adam17 variant in primary fibroblast cells.
Xiaoxiao Wang, Chaolan Pan, Luyao Zheng, Jianbo Wang, Quan Zou, Peiyi Sun, Kaili Zhou, Anqi Zhao, Qiaoyu Cao, Wei He, Yumeng Wang, Ruhong Cheng, Zhirong Yao, Si Zhang, Hui Zhang, Ming Li
Alloreactive memory, unlike naïve, CD8+ T cells resist transplantation tolerance protocols and are a critical barrier to long-term graft acceptance in the clinic. We here show that semi-allogeneic pregnancy successfully reprogrammed memory fetus/graft-specific CD8+ T cells (TFGS) towards hypofunction. Female C57BL/6 mice harboring memory CD8+ T cells generated by the rejection of BALB/c skin grafts and then mated with BALB/c males achieved rates of pregnancy comparable to naive controls. Post-partum fetus/graft-specific CD8+ T cells (TFGS) from skin-sensitized dams upregulated expression of T cell exhaustion (TEX) markers (Tox, Eomes, PD-1, TIGIT, and Lag3). Transcriptional analysis corroborated an enrichment of canonical T exhaustion (TEX) genes in post-partum memory TFGS and additionally, revealed a downregulation of a subset of memory-associated transcripts. Strikingly, pregnancy induced extensive epigenetic modifications of exhaustion- and memory-associated genes in memory TFGS, whereas minimal epigenetic modifications were observed in naive TFGS cells. Finally, post-partum memory TFGS durably expressed the exhaustion-enriched phenotype, and their susceptibility to transplantation tolerance was significantly restored compared to memory TFGS. These findings advance the concept of pregnancy as an epigenetic modulator inducing hypofunction in memory CD8+ T cells that has relevance not only for pregnancy and transplantation tolerance, but also for tumor immunity and chronic infections.
Jared M. Pollard, Grace Hynes, Dengping Yin, Malay Mandal, Fotini Gounari, Maria-Luisa Alegre, Anita S. Chong
Glycogen storage disease type III (GSDIII) is a rare metabolic disorder due to glycogen debranching enzyme (GDE) deficiency. Reduced GDE activity leads to pathological glycogen accumulation responsible for impaired hepatic metabolism and muscle weakness. To date, there is no curative treatment for GSDIII. We previously reported that two distinct dual AAV vectors encoding for GDE were needed to correct liver and muscle in a GSDIII mouse model. Here, we evaluated the efficacy of rapamycin in combination with AAV gene therapy. Simultaneous treatment with rapamycin and a novel dual AAV vector expressing GDE in the liver and muscle resulted in a synergic effect demonstrated at biochemical and functional levels. Transcriptomic analysis confirmed synergy and suggested a putative mechanism based on the correction of lysosomal impairment. In GSDIII mice liver, dual AAV gene therapy combined with rapamycin reduced the impact of the immune response to AAV observed in this disease model. These data provide proof of concept of an approach exploiting the combination of gene therapy and rapamycin to improve efficacy and safety and support clinical translation.
Louisa Jauze, Mallaury Vie, Quentin Miagoux, Lucille Rossiaud, Patrice Vidal, Valle Montalvo-Romeral, Hanadi Saliba, Margot Jarrige, Helene Polveche, Justine Nozi, Pierre-Romain Le Brun, Luca Bocchialini, Amandine Francois, Jeremie Cosette, Jérémy Rouillon, Fanny Collaud, Fanny Bordier, Emilie Bertil-Froidevaux, Christophe Georger, Laetitia Van Wittenberghe, Adeline Miranda, Nathalie Daniele, David Gross, Lucile Hoch, Xavier Nissan, Giuseppe Ronzitti
Diabetes increases the risk of both cardiovascular disease and kidney disease. Notably, most of the excess cardiovascular risk in people with diabetes is in those with kidney disease. Apolipoprotein C3 (APOC3) is a key regulator of plasma triglycerides, and it has recently been suggested to play a role in both type 1 diabetes-accelerated atherosclerosis and kidney disease progression. To investigate if APOC3 plays a role in kidney disease in people with type 2 diabetes, we analyzed plasma levels of APOC3 from the Veterans Affairs Diabetes Trial (VADT). Elevated baseline APOC3 levels predicted a greater loss of renal function. To mechanistically test if APOC3 plays a role in diabetic kidney disease and associated atherosclerosis, we treated BTBR wildtype (WT) and leptin-deficient (OB; diabetic) mice, a model of type 2 diabetes, with an antisense oligonucleotide (ASO) to APOC3 or a control ASO (cASO), all in the setting of human-like dyslipidemia. Silencing APOC3 prevented diabetes-augmented albuminuria, renal glomerular hypertrophy, monocyte recruitment, and macrophage accumulation, partly driven by reduced ICAM1 expression. Furthermore, reduced levels of APOC3 suppressed atherosclerosis associated with diabetes. This suggests that targeting APOC3 might benefit both diabetes-accelerated atherosclerosis and kidney disease.
Jocelyn Cervantes, Juraj Koska, Farah Kramer, Shreeram Akilesh, Charles E. Alpers, Adam E. Mullick, Peter Reaven, Jenny E. Kanter
Juvenile Dermatomyositis (JDM) is one of several childhood-onset autoimmune disorders characterized by a type I interferon response and autoantibodies. Treatment options are limited due to incomplete understanding of how the disease emerges from dysregulated cell states across the immune system. We therefore investigated the blood of JDM patients at different stages of disease activity using single-cell transcriptomics paired with surface protein expression. By immunophenotyping peripheral blood mononuclear cells, we observed skewing of the B cell compartment towards an immature naive state as a hallmark of JDM at diagnosis. Furthermore, we find that these changes in B cells are paralleled by T cell signatures suggestive of Th2-mediated inflammation that persist despite disease quiescence. We applied network analysis to reveal that hyperactivation of the type I interferon response in all immune populations is coordinated with previously masked cell states including dysfunctional protein processing in CD4+ T cells and regulation of cell death programming in NK, CD8+ T cells and gdT cells. Together, these findings unveil the coordinated immune dysregulation underpinning JDM and provide insight into strategies for restoring balance in immune function.
Gabrielle Rabadam, Camilla Wibrand, Emily Flynn, George C. Hartoularos, Yang Sun, Chioma Madubata, Gabriela K. Fragiadakis, Jimmie Ye, Susan Kim, Zev J. Gartner, Marina Sirota, Jessica Neely
Applying advanced molecular profiling together with highly specific targeted therapies offers the possibility to better dissect the mechanisms underlying immune mediated inflammatory diseases such as systemic lupus erythematosus (SLE) in humans. Here we apply a combination of single cell RNA sequencing and T/B cell repertoire analysis to perform an in-depth characterization of molecular changes in the immune-signature upon CD19 CAR T cell-mediated depletion of B cells in SLE patients. The resulting datasets do not only confirm a selective CAR T cell-mediated reset of the B cell response, but simultaneously reveal consequent changes in the transcriptional signature of monocyte and T cell subsets that respond with a profound reduction in type 1 interferon signaling. Our current data thus provide evidence for a causal relationship between the B cell response and the increased interferon signature observed in SLE and additionally demonstrate the usefulness of combining targeted therapies and novel analytic approaches to decipher molecular mechanisms of immune-mediated inflammatory diseases in humans.
Artur Wilhelm, David Chambers, Fabian Müller, Aline Bozec, Ricardo Grieshaber-Bouyer, Thomas Winkler, Dimitrios Mougiakakos, Andreas Mackensen, Georg Schett, Gerhard Krönke
Thermogenesis in beige/brown adipose tissues can be leveraged to combat metabolic disorders such as type 2 diabetes and obesity. The complement system plays pleiotropic roles in metabolic homeostasis and organismal energy balance with canonical effects on immune cells and non-canonical effects on non-immune cells. The adipsin/C3a/C3aR1 pathway stimulates insulin secretion and sustains pancreatic beta cell mass. However, its role in adipose thermogenesis has not been defined. Here, we show that male Adipsin/Cfd knockout mice exhibit increased energy expenditure and white adipose tissue (WAT) browning. In addition, male adipocyte-specific C3aR1 knockout mice exhibit enhanced WAT thermogenesis and increased respiration. In stark contrast, female adipocyte-specific C3aR1 knockout mice display decreased brown fat thermogenesis and are cold intolerant. Female mice express lower levels of Adipsin in thermogenic adipocytes and adipose tissues than males. C3aR1 is also lower in female subcutaneous adipose tissue than males. Collectively, these results reveal sexual dimorphism in the adipsin/C3a/C3aR1 axis in regulating adipose thermogenesis and defense against cold stress. Our findings establish a newly discovered role of the alternative complement pathway in adaptive thermogenesis and highlight sex-specific considerations in potential therapeutic targets for metabolic diseases.
Lunkun Ma, Ankit Gilani, Alfonso Rubio-Navarro, Eric Cortada, Ang Li, Shannon M. Reilly, Liling Tang, James C. Lo
Inhibition of Bruton's tyrosine kinase (BTK) through covalent modifications of its active site (e.g., ibrutinib [IBT]) is a preferred treatment for multiple B cell malignancies. However, IBT-treated patients are more susceptible to invasive fungal infections, although the mechanism is poorly understood. Neutrophils are the primary line of defense against these infections; therefore, we examined the impact of IBT on primary human neutrophil effector activity against Aspergillus fumigatus. IBT significantly impaired the ability of neutrophils to kill A. fumigatus and potently inhibited reactive oxygen species (ROS) production, chemotaxis, and phagocytosis. Importantly, exogenous TNFα fully compensated for defects imposed by IBT and newer-generation BTK inhibitors and restored the ability of neutrophils to contain A. fumigatus hyphal growth. Blocking TNFα did not impact ROS production in healthy neutrophils but prevented exogenous TNFα from rescuing the phenotype of IBT-treated neutrophils. The restorative capacity of TNFα was independent of transcription. Moreover, the addition of TNFα immediately rescued ROS production in IBT-treated neutrophils indicating that TNFα worked through a BTK-independent signaling pathway. Finally, TNFα restored effector activity of primary neutrophils from patients on IBT therapy. Altogether, our data indicate that TNFα rescues the antifungal immunity block imposed by inhibition of BTK in primary human neutrophils.
Diego A. Vargas-Blanco, Olivia W. Hepworth, Kyle J. Basham, Patricia Simaku, Arianne J. Crossen, Kyle D. Timmer, Alex Hopke, Hannah Brown Harding, Steven R. Vandal, Kirstine N. Jensen, Daniel J. Floyd, Jennifer L. Reedy, Christopher Reardon, Michael K. Mansour, Rebecca A. Ward, Daniel Irimia, Jeremy S. Abramson, Jatin M. Vyas
Astrocyte activation is a common feature of neurodegenerative diseases. However, the ways in which dying neurons influence the activity of astrocytes is poorly understood. Receptor interacting protein kinase-3 (RIPK3) signaling has recently been described as a key regulator of neuroinflammation, but whether this kinase mediates astrocytic responsiveness to neuronal death has not yet been studied. Here, we used the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson’s disease to show that activation of astrocytic RIPK3 drives dopaminergic cell death and axon damage. Transcriptomic profiling revealed that astrocytic RIPK3 promoted gene expression associated with neuroinflammation and movement disorders, and this coincided with significant engagement of damage associated molecular pattern (DAMP) signaling. In mechanistic experiments, we show that factors released from dying neurons signal through receptor for advanced glycation endproducts (RAGE) to induce astrocytic RIPK3 signaling, which conferred inflammatory and neurotoxic functional activity. These findings highlight a mechanism of neuron-glia crosstalk in which neuronal death perpetuates further neurodegeneration by engaging inflammatory astrocyte activation via RIPK3.
Nydia P. Chang, Evan M. DaPrano, Marissa Lindman, Irving Estevez, Tsui-Wen Chou, Wesley R. Evans, Marialaina Nissenbaum, Micheal McCourt, Diego Alzate, Colm Atkins, Alexander W. Kusnecov, Rafiq Huda, Brian P. Daniels