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NK cell subsets define sustained remission in rheumatoid arthritis

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Abstract

Rheumatoid Arthritis (RA) is an immune-mediated, chronic inflammatory condition. With modern therapeutics and evidence-based management strategies, achieving sustained remission is increasingly common. To prevent complications associated with prolonged use of immunosuppressants, drug tapering or withdrawal is recommended. However, due to the lack of tools that define immunological remission, disease flares are frequent, highlighting the need for a more precision medicine-based approach. Utilising high dimensional phenotyping platforms, we set out to define peripheral blood immunological signatures of sustained remission in RA. We identified that CD8+CD57+KIR2DL1+ NK cells are associated with sustained remission. Functional studies uncovered an NK cell subset characterized by normal degranulation responses and reduced pro-inflammatory cytokine expression, which was elevated in sustained remission. Furthermore, flow cytometric analysis of NK cells from synovial fluid combined with interrogation of a publicly available single cell RNA-seq dataset of synovial tissue from active RA identified a deficiency of the phenotypic characteristics associated with this NK cell remission signature. In summary, we have uncovered a novel RA remission signature associated with compositional changes in NK cell phenotype and function that has implications for understanding the impact of sustained remission on host immunity and distinct features which may define operational tolerance in RA.

Authors

Carl Coyle, Margaret Ma, Yann Abraham, Christopher B. Mahony, Kathryn Steel, Catherine Simpson, Nadia Guerra, Adam P. Croft, Stephen Rapecki, Andrew Cope, Rowann Bowcutt, Esperanza Perucha

Identification of LRP1+CD13+ human periosteal stem cells that require LRP1 for bone repair

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Abstract

Human periosteal skeletal stem cells (P-SSCs) are critical for cortical bone maintenance and repair. However, their in vivo identity, molecular characteristics, and specific markers remain unknown. Here, single-cell sequencing revealed human periosteum contains SSC clusters expressing known SSC markers, PDPN and PDGFRA. Notably, human P-SSCs, but not bone marrow SSCs (BM-SSCs), selectively expressed newly identified markers, LRP1 and CD13. These LRP1+CD13+ human P-SSCs were perivascular cells with high osteochondrogenic but minimal adipogenic potential. Upon transplantation into bone injuries in mice, they preserved self-renewal capability in vivo. Single-cell analysis of mouse periosteum further supported the preferential expression of LRP1 and CD13 in Prx1+ P-SSCs. When Lrp1 was conditionally deleted in Prx1-lineage cells, it led to severe bone deformity, short statue, and periosteal defects. By contrast, local treatment with a LRP1 agonist at the injury sites induced early P-SSC proliferation and bone healing. Thus, human and mouse periosteum contains unique osteochondrogenic stem cell subsets, and these P-SSCs express specific markers, LRP1 and CD13, with regulatory mechanism through LRP1 that enhances P-SSC function and bone repair.

Authors

Youngjae Jeong, Lorenzo R. Deveza, Laura Ortinau, Kevin Lei, John R. Dawson, Dongsu Park

Type 2 innate immunity promotes the development of pulmonary fibrosis in Hermansky-Pudlak syndrome

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Abstract

Hermansky-Pudlak syndrome (HPS), particularly in types 1 and 4, is characterized by progressive pulmonary fibrosis, a major cause of morbidity and mortality. However, the precise mechanisms driving pulmonary fibrosis in HPS are not fully elucidated. Our previous studies suggested that CHI3L1-driven fibroproliferation may be a notable factor in HPS-associated fibrosis. This study aimed to explore the role of CHI3L1-CRTH2 interaction on ILC2s and explored the potential contribution of ILC2-fibroblast crosstalk in the development of pulmonary fibrosis in HPS. We identified ILC2s in lung tissues from idiopathic pulmonary fibrosis (IPF) and HPS patients. Using bleomycin-challenged wild type (WT) and Hps1–/– mice we observed that ILC2s were recruited and appeared to contribute to fibrosis development in the Hps1–/– mice, with CRTH2 playing a notable role in ILC2 accumulation. We sorted ILC2s, profiled fibrosis-related genes and mediators, and conducted co-culture experiments with primary lung ILC2s and fibroblasts. Our findings suggest that ILC2s may directly stimulate the proliferation and differentiation of primary lung fibroblasts partially through Amphiregulin-EGFR-dependent mechanisms. Additionally, specific overexpression of CHI3L1 in the ILC2 population using the IL-7Rcre driver, which was associated with increased fibroproliferation, indicates that ILC2-mediated, CRTH2-dependent mechanisms might contribute to optimal CHI3L1-induced fibroproliferative repair in HPS-associated pulmonary fibrosis.

Authors

Parand Sorkhdini, Kiran Klubock-Shukla, Selena Sheth, Dongqin Yang, Alina Xiaoyu Yang, Carmelissa Norbrun, Wendy J. Introne, Bernadette R. Gochuico, Yang Zhou

Loss of PADI2 and PADI4 ameliorates sepsis-induced acute lung injury by suppressing NLRP3⁺ macrophages

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Abstract

Sepsis-induced acute lung injury (ALI) is prevalent in septic patients and has a high mortality rate. Peptidyl arginine deiminase (PADI) 2 and PADI4 play crucial roles in mediating the host’s immune response in sepsis, but their specific functions remain unclear. Our study shows that Padi2–/–Padi4–/– double knockout (DKO) improved survival, reduced lung injury, decreased bacterial load in Pseudomonas aeruginosa (PA) pneumonia-induced sepsis mice. Using single-cell RNA sequencing (scRNA-seq), we found that the deletion of Padi2 and Padi4 reduced the Nlrp3+ pro-inflammatory macrophages and fostered Chil3+ myeloid cell differentiation into anti-inflammatory macrophages. Additionally, we observed the regulatory role of NLRP3-Ym1 axis upon DKO, confirmed by Chil3 knockdown and Nlrp3 KO experiments. Thus, eliminating Padi2 and Padi4 enhances the polarization of Ym1+ M2 macrophages by suppressing NLRP3, aiding in inflammation resolution and lung tissue repair. study unveils the PADI2/PADI4-NLRP3-Ym1 pathway as a potential target in treatment of sepsis-induced ALI.

Authors

Xin Yu, Yujing Song, Tao Dong, Wenlu Ouyang, Liujiazi Shao, Chao Quan, Kyung Eun Lee, Tao Tan, Allan Tsung, Katsuo Kurabayashi, Hasan B. Alam, Mao Zhang, Jianjie Ma, Yongqing Li

ClC-Kb pore mutation disrupts glycosylation and triggers distal tubular remodeling

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Abstract

Mutations in the CLCNKB gene (1p36), encoding a basolateral chloride channel, ClC-Kb, cause type 3 Bartter’s syndrome. We identified a family with a mixed Bartter’s / Gitelman’s phenotype and early-onset kidney failure and employing a candidate gene approach, discovered a homozygous mutation (CLCNKB c.499G>T [p.Gly167Cys]) in exon 6 of CLCNKB in the index patient. We then validated these results with Sanger and whole exome sequencing. Compared to wild-type ClC-Kb, the Gly167Cys mutant conducted less current and impaired, complex N-linked glycosylation in vitro. We demonstrated that loss of Gly-167, rather than gain of a mutant Cys, impairs complex glycosylation but that surface expression remains intact. Moreover, Asn364 was necessary for channel function and complex glycosylation. Morphologic evaluation of human kidney biopsies revealed typical basolateral localization of mutant Gly167Cys ClC-Kb in cortical distal tubular epithelia. However, we detected attenuated expression of distal sodium transport proteins, changes in abundance of distal tubule segments, and hypokalemia-associated intracellular condensates from the index patient compared to control nephrectomy specimens. The present data establish what we believe, are novel regulatory mechanisms of ClC-Kb activity and demonstrate nephron remodeling in man, caused by mutant ClC-Kb, with implications for renal electrolyte handling, blood pressure control, and kidney disease.

Authors

Yogita Sharma, Robin Lo, Viktor N. Tomilin, Kotdaji Ha, Holly Deremo, Aishwarya V. Pareek, Wuxing Dong, Xiaohui Liao, Svetlana Lebedeva, Vivek Charu, Neeraja Kambham, Kerim Mutig, Oleh Pochynyuk, Vivek Bhalla

Longitudinal lipidomic profiles of left ventricular mass and hypertrophy in American Indians

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Abstract

Left ventricular hypertrophy (LVH) and dyslipidemia are strong, independent predictors for cardiovascular disease, but their relationship is less well-studied. A longitudinal lipidomic profiling of left ventricular mass (LVM) and LVH is still lacking. Using LC-MS, we repeatedly measured 1,542 lipids from 1,755 unique American Indians attending two exams (mean~5-year apart). Cross-sectional associations of individual lipid species with LVM index (LVMI) were examined by generalized estimating equation (GEE), followed by replication in an independent bi-racial cohort (65% white, 35% black). Baseline plasma lipids associated with LVH risk beyond traditional risk factors were identified by Cox frailty model in American Indians. Longitudinal associations between changes in lipids and changes in LVMI were examined by GEE, adjusting for baseline lipids, baseline LVMI, and covariates. Multiple lipid species (e.g., glycerophospholipids, sphingomyelins, acylcarnitines) were significantly associated with LVMI or the risk of LVH in American Indians. Some lipids were confirmed in black and white individuals. Moreover, some LVH-related lipids were inversely associated with risk of coronary heart disease (CHD). Longitudinal changes in several lipid species (e.g., glycerophospholipids, sphingomyelins, cholesterol esters) were significantly associated with changes in LVMI. These findings provide insights into the role of lipid metabolism in LV remodeling and the risk of LVH or CHD.

Authors

Mingjing Chen, Zhijie Huang, Guanhong Miao, Jin Ren, Jinling Liu, Mary J. Roman, Richard B. Devereux, Richard R. Fabsitz, Ying Zhang, Jason G. Umans, Shelley A. Cole, Tanika N. Kelly, Oliver Fiehn, Jinying Zhao

More women than ever are entering MD-PhD programs. What lies ahead for them?

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Abstract

The earliest MD/PhD programs were small and enrolled mostly men. Here we show that since 2014 there has been a steady increase in the number of women in MD/PhD programs, reaching parity with men in 2023. This change was due to an increase in female applicants, a decrease in male applicants, and an increase in the acceptance rate for women, which had previously been lower than for men. Data from the National MD/PhD Program Outcomes Study show that training duration has been similar for men and women, as have most choices of medical specialties and workplaces. However, women were less likely to have full-time faculty appointments, fewer had NIH grants, and those in the most recent graduation cohort at the time of the survey reported spending less time on research than men. Previously-cited reasons for these differences include disproportionate childcare responsibilities, a paucity of role models, insufficient recognition, and gender bias. Institutions can and should address these obstacles, but training programs can help by preparing their graduates to succeed despite the systemic obstacles. The alternative is a persistent gender gap in the physician-scientist workforce, lost opportunities to benefit from diverse perspectives, and a diminished impact of valuable training resources.

Authors

Lawrence F. Brass, Myles H. Akabas

Tissue resident memory T cells contribute to protection against heterologous SARS-CoV-2 challenge

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Abstract

Widespread vaccination and natural infection have resulted in greatly decreased rates of severe disease, hospitalization and death after subsequent infection or reinfection with SARS-CoV-2. New vaccine formulations are based on circulating strains of virus, which have tended to evolve to more readily transmit human to human and to evade the neutralizing antibody response. An assumption of this approach is that ancestral strains of virus will not recur. Recurrence of these strains could be a problem for individuals not previously exposed to ancestral spike protein by vaccination or infection. Here, we addressed this question by infecting mice with recent SARS-CoV-2 variants and then challenging them with a highly pathogenic mouse-adapted virus closely related to the ancestral Wuhan-1 strain (SARS2-N501YMA30). We found that challenged mice were protected from death and substantial weight loss, even though they generally had low or no neutralizing antibody response to SARS2-N501YMA30 at the time of reinfection. T cell depletion from the previously infected mice did not diminish infection against clinical disease, although it did result in delayed kinetics of virus clearance in the nasal turbinate and in some cases, in the lungs. Levels of tissue resident memory T cells were significantly elevated in the nasal turbinate of previously infected mice compared to mice that had no previous exposure to SARS-CoV-2. However, this phenotype was not seen in lung tissues. Together, these results indicate that the immune response to newly circulating variants afforded protection against re-infection with the ancestral virus that was at least in part T cell based.

Authors

Abby Odle, Meenakshi Kar, Abhishek K. Verma, Alan Sariol, David K. Meyerholz, Mehul S. Suthar, Lok-Yin Roy Wong, Stanley Perlman

Pharmacologic or genetic interference with atrogene signaling protects from glucocorticoid-induced musculoskeletal and cardiac disease

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Abstract

Despite their beneficial actions as immunosuppressants, glucocorticoids (GC) have devastating effects on the musculoskeletal and cardiac systems, as long-term treated patients exhibit high incidence of falls, bone fractures, and cardiovascular events. Herein, we show that GC upregulate simultaneously in bone, skeletal muscle, and the heart, the expression of E3 ubiquitin ligases (atrogenes), known to stimulate the proteasomal degradation of proteins. Activation of Vitamin D receptor (VDR) signaling with the VDR ligands 1,25D3 (calcitriol, 1,25-dihydroxyvitamin D3) or ED (eldecalcitol, 2β-(3-hydroxypropyloxy)-1,25-dihydroxyvitamin D3) prevented GC-induced atrogene upregulation in vivo and ex vivo in bone/muscle organ cultures and preserved tissue structure/mass and function of three tissues in vivo. Direct pharmacologic inhibition of the proteasome with carfilzomib also conferred musculoskeletal protection. Genetic loss of the atrogene MuRF1-mediated protein ubiquitination in ∆RING mice afforded temporary or sustained protection from GC excess in bone, or skeletal and heart muscle, respectively. We conclude that the atrogene pathway downstream of MuRF1 underlies GC action in bone, muscle, and the heart, and it can be pharmacologically or genetically targeted to confer protection against the damaging actions of GC simultaneously in the three tissues.

Authors

Amy Y. Sato, Meloney Cregor, Kevin McAndrews, Charles A. Schurman, Eric Schaible, Jennifer Shutter, Punit Vyas, Bhawana Adhikari, Monte S. Willis, Marjan Boerma, Tamara Alliston, Teresita Bellido

Molecular basis of cell membrane adaptation in daptomycin-resistant Enterococcus faecalis

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Abstract

Daptomycin is a last resort lipopeptide antibiotic that disrupts cell membrane (CM) and peptidoglycan homeostasis. Enterococcus faecalis has developed a sophisticated mechanism to avoid daptomycin killing by re-distributing CM anionic phospholipids away from the septum. The CM changes are orchestrated by a three-component regulatory system, designated LiaFSR, with a possible contribution of cardiolipin synthase (Cls). However, the mechanism by which LiaFSR controls the CM response and the role of Cls are unknown. Here, we show that cardiolipin synthase activity is essential for anionic phospholipid redistribution and daptomycin resistance since deletion of the two genes (cls1 and cls2) encoding Cls abolished CM remodeling. We identified LiaY, a transmembrane protein regulated by LiaFSR, and Cls1 as important mediators of CM remodeling required for re-distribution of anionic phospholipid microdomains. Together, our insights provide a mechanistic framework on the enterococcal response to cell envelope antibiotics that could be exploited therapeutically.

Authors

April H. Nguyen, Truc T. Tran, Diana Panesso, Kara S. Hood, Vinathi Polamraju, Rutan Zhang, Ayesha Khan, William R. Miller, Eugenia Mileykovskaya, Yousif Shamoo, Libin Xu, Heidi Vitrac, Cesar A. Arias

High-dimensional analysis of NK cells in kidney transplantation uncovers subsets associated with antibody-independent graft dysfunction

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Abstract

Natural Killer (NK) cells respond to diseased and allogeneic cells through NKG2A/HLA-E or Killer-cell Immunoglobulin-like receptor (KIR)/HLA-ABC interactions. Correlations between HLA/KIR disparities and kidney transplant pathology suggest an antibody-independent pathogenic role for NK cells in transplantation, but mechanisms remain unclear. Using CyTOF to characterize recipient peripheral NK cell phenotypes and function, we observed diverse NK cell subsets amongst participants that responded heterogeneously to allo-stimulators. NKG2A+/KIR+ NK cells responded more vigorously than other subsets, and this heightened response persisted post-kidney-transplant despite immunosuppression. In test and validation sets from two clinical trials, pre-transplant donor-induced release of cytotoxicity mediator, Ksp37, by NKG2A+ NK cells correlated with reduced long-term allograft function. Separate analyses showed Ksp37 gene expression in allograft biopsies lacking histological rejection correlated with death censored graft loss. Our findings support an antibody-independent role for NK cells in transplant injury and support further testing of pre-transplant, donor-reactive, NK cell-produced Ksp37 as a risk-assessing, transplantation biomarker.

Authors

Dan Fu Ruan, Miguel Fribourg, Yuko Yuki, Yeon-Hwa Park, Maureen P. Martin, Haocheng Yu, Geoffrey C. Kelly, Brian H. Lee, Ronaldo M. de Real, Rachel Lee, Daniel Geanon, Seunghee Kim-Schulze, Nicholas Chun, Paolo Cravedi, Mary Carrington, Peter S. Heeger, Amir Horowitz

Cell cycle inhibitors activate hypoxia-induced DDX41-STING pathway to mediate anti-tumor immune response in liver cancer

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Abstract

Cell cycle inhibitors have a long history as cancer treatment. Here, we reported that these inhibitors combated cancer partially via Stimulator of IFN genes (STING) signaling pathway. We demonstrated that Paclitaxel (microtubule stabilizer), Palbociclib (cyclin dependent kinase 4/6 inhibitor), AZD1152 and GSK1070916 (aurora kinase B inhibitors) have anti-cancer functions beyond arresting cell cycle. They consistently caused cytosolic DNA accumulation and DNA damage, which inadvertently triggered the cytosolic DNA sensor DEAD-box helicase 41 (DDX41) and activated STING to secrete pro-inflammatory senescence-associated secretory phenotype factors (SASPs). Interestingly, we found that DDX41 was a transcriptional target of HIF. Hypoxia induced expression of DDX41 through HIF-1, making hypoxic HCC cells more sensitive to the anti-mitotic agents in STING activation and SASP production. The SASPs triggered immune cell infiltration in tumors for cancer clearance. The treatment of cell cycle inhibitors, especially Paclitaxel, extends survival by perturbing mouse HCC growth when used in combination with anti-PD-1. We observed a trend that Paclitaxel suppressed STINGWT HCC more effectively than STINGKO HCC, suggesting that STING might contribute to the anti-tumor effects of Paclitaxel. Our study revealed the immune-mediated tumor-suppressing properties of cell cycle inhibitors and suggested combined treatment with immunotherapy as a potential therapeutic approach.

Authors

Po Yee Wong, Cerise Yuen Ki Chan, Helen Do Gai Xue, Chi Ching Goh, Jacinth Wing Sum Cheu, Aki Pui Wah Tse, Misty Shuo Zhang, Yan Zhang, Carmen Chak Lui Wong

Giantin mediates Golgi localization of Gal3-O-sulfotransferases and affects salivary mucin sulfation in Sjögren’s disease patients

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Abstract

Sjögren’s disease is a chronic autoimmune disease characterized by symptoms of oral and ocular dryness and extra-glandular manifestations. Mouth dryness is not only due to reduced saliva volume but also to alterations in the quality of salivary mucins in these patients. Mucins play a leading role in mucosa hydration and protection, where sulfated and sialylated oligosaccharides retain water molecules at the epithelial surface. The correct localization of glycosyltransferases and sulfotransferases within the Golgi apparatus determines adequate O-glycosylation and sulfation of mucins, which depends on specific golgins that tether enzyme-bearing vesicles. Here, we show that a golgin called Giantin is mislocalized in salivary glands from patients with Sjögren’s disease and forms protein complexes with Gal3-O-sulfotransferases (Gal3STs), which change their localization in Giantin knockout and knockdown cells. Our results suggest that Giantin could tether Gal3ST-bearing vesicles and that its altered localization could affect Gal3ST activity, explaining the decreased sulfation of MUC5B observed in salivary glands from patients with Sjögren’s disease.

Authors

Matilde Nuñez, Patricia Carvajal, Sergio Aguilera, María-José Barrera, Soledad Matus, Alicia Couto, Malena Landoni, Gaelle Boncompain, Sergio González, Claudio Molina, Karina Pino, Sebastián Indo, Lourdes Figueroa, María-Julieta González, Isabel Castro

TET2 promotes tumor antigen presentation and T cell IFN-γ which is enhanced by vitamin C

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Abstract

Immune evasion by tumors is promoted by low T cell infiltration, ineffective T cell activity directed against the tumor and reduced tumor antigen presentation. The TET2 DNA dioxygenase gene is frequently mutated in hematopoietic malignancies and loss of TET enzymatic activity is found in a variety of solid tumors. We showed previously that vitamin C (VC), a co-factor of TET2, enhances tumor-associated T cell recruitment and checkpoint inhibitor therapy responses in a TET2-dependent manner. Using single-cell RNA sequencing (scRNA-seq) analysis performed on B16-OVA melanoma tumors, we have shown here that an additional function for TET2 in tumors is to promote expression of certain antigen presentation machinery genes, which is potently enhanced by VC. Consistently, VC promoted antigen presentation in cell-based and tumor assays in a TET2-dependent manner. Quantifying intercellular signaling from the scRNA-seq dataset showed that T cell-derived IFNγ-induced signaling within the tumor and tumor microenvironment requires tumor-associated TET2 expression which is enhanced by VC treatment. Analysis of patient tumor samples indicated that TET activity directly correlates with antigen-presentation gene expression and with patient outcomes. Our results demonstrate the importance of tumor-associated TET2 activity as a critical mediator of tumor immunity which is augmented by high-dose VC therapy.

Authors

Meng Cheng, Angel Ka Yan Chu, Zhijun Li, Sabrina Yang, Matthew D. Smith, Qi Zhang, Nicholas G. Brown, William F. Marzluff, Nabeel Bardeesy, J. Justin Milner, Joshua D. Welch, Yue Xiong, Albert S. Baldwin

O-GlcNAcylation modulates mTORC1 and autophagy in β-cells, driving diabetes progression

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Abstract

Type 2 diabetes (T2D) arises when pancreatic β-cells fail to produce sufficient insulin to control blood glucose appropriately. Aberrant nutrient sensing by O-GlcNAcylation and mTORC1 is linked to T2D and the failure of insulin-producing β-cells. However, the nature of their crosstalk in β-cells remains unexplored. Recently, O-GlcNAcylation, a post-translation modification controlled by enzymes OGT/OGA, emerged as a pivotal regulator for β-cell health; deficiency in either enzyme causes β-cell failure. The present study investigates the previously unidentified connection between nutrient sensor OGT and mTORC1 crosstalk to regulate β-cell mass and function in vivo. We show reduced OGT and mTORC1 activity in islets of preclinical β-cell dysfunction model and obese human islets. Using loss or gain of function of OGT, we identified that O-GlcNAcylation positively regulates mTORC1 signaling in β-cells. O-GlcNAcylation negatively modulates autophagy, as the removal of OGT increases autophagy, while the deletion of OGA decreases it. Increasing mTORC1 signaling, via deletion of TSC2, alleviates the diabetic phenotypes by increasing β-cell mass but not β-cell function in OGT deficient mice. Downstream phospho-protein signaling analysis reveal diverging impact on MKK4 and calmodulin signaling between islets with OGT, TSC2, or combined deletion. These data provide new evidence of OGT's significance as an upstream regulator of mTORC1 and autophagy, crucial for the regulation of β-cell function and glucose homeostasis.

Authors

Seokwon Jo, Nicholas Esch, Anh Nguyen, Alicia Wong, Ramkumar Mohan, Clara Kim, Manuel Blandino-Rosano, Ernesto Bernal-Mizrachi, Emilyn U. Alejandro

Hematopoietic PI3Kδ deficiency aggravates murine atherosclerosis through impairment of regulatory T cells

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Abstract

Chronic activation of the adaptive immune system is a hallmark of atherosclerosis. As PI3Kδ is a key regulator of T and B-cell differentiation and function, we hypothesized that alleviation of adaptive immunity by PI3Kδ inactivation may represent an attractive strategy counteracting atherogenesis. As expected, lack of hematopoietic PI3Kδ in atherosclerosis-prone Ldlr–/– mice resulted in hindered T- and B-cell numbers, CD4+ effector T cells, Th1 response, and immunoglobulin levels. However, despite markedly impaired peripheral proinflammatory Th1 cells and atheromatous CD4+ T cells, the unexpected net effect of hematopoietic PI3Kδ deficiency was aggravated vascular inflammation and atherosclerosis. Further analyses revealed that PI3Kδ deficiency impaired numbers, immunosuppressive functions, and stability of regulatory CD4+ T cells (Tregs), whereas macrophage biology remained largely unaffected. Adoptive transfer of wild-type Tregs fully restrained the atherosclerotic plaque burden in Ldlr–/– mice lacking hematopoietic PI3Kδ, whereas PI3Kδ deficient Tregs failed to mitigate disease. Numbers of atheroprotective B-1 and proatherogenic B-2 cells as well serum immunoglobulin levels remained unaffected by adoptively transferred wild-type Tregs. In conclusion, we demonstrate that hematopoietic PI3Kδ ablation promotes atherosclerosis. Mechanistically, we identified PI3Kδ signaling as a powerful driver of atheroprotective Treg responses, which outweigh PI3Kδ driven proatherogenic effects of adaptive immune cells like Th1 cells.

Authors

Mario Zierden, Eva Maria Berghausen, Leoni Gnatzy-Feik, Christopher Millarg, Felix Simon Ruben Picard, Martha Kiljan, Simon Geißen, Apostolos Polykratis, Lea Zimmermann, Richard Julius Nies, Manolis Pasparakis, Stephan Baldus, Chanil Valasarajan, Soni Savai Pullamsetti, Holger Winkels, Marius Vantler, Stephan Rosenkranz

Glucocorticoid chrono-pharmacology promotes glucose metabolism in heart through a cardiomyocyte-autonomous transactivation program

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Abstract

Circadian time-of-intake gates the cardioprotective effects of glucocorticoid administration in both healthy and infarcted hearts. The cardiomyocyte-specific glucocorticoid receptor (GR) and its co-factor, Krüppel-like factor (Klf15), play critical roles in maintaining normal heart function in the long-term and serve as pleiotropic regulators of cardiac metabolism. Despite this understanding, the cardiomyocyte-autonomous metabolic targets influenced by the concerted epigenetic action of GR-Klf15 axis remain undefined. Here, we demonstrate the critical roles of the cardiomyocyte-specific GR and Klf15 in orchestrating a circadian-dependent glucose oxidation program within the heart. Combining integrated transcriptomics and epigenomics with cardiomyocyte-specific inducible ablation of GR or Klf15, we identified their synergistic role in the activation of adiponectin receptor expression (Adipor1) and the mitochondrial pyruvate complex (Mpc1/2), thereby enhancing insulin-stimulated glucose uptake and pyruvate oxidation. Furthermore, in obese diabetic (db/db) mice exhibiting insulin resistance and impaired glucose oxidation, light-phase prednisone administration, as opposed to dark-phase prednisone dosing, effectively restored cardiomyocyte glucose oxidation and improved diastolic function towards control-like levels in a sex-independent manner. Collectively, our findings uncover novel cardiomyocyte-autonomous metabolic targets of the GR-Klf15 axis. This study highlights the circadian-dependent cardioprotective effects of glucocorticoids on cardiomyocyte glucose metabolism, providing critical insights into chrono-pharmacological strategies for glucocorticoid therapy in cardiovascular disease.

Authors

Hima Bindu Durumutla, Ashok Prabakaran, Fadoua El Abdellaoui Soussi, Olukunle Akinborewa, Hannah Latimer, Kevin McFarland, Kevin Piczer, Cole Werbrich, Mukesh K. Jain, Saptarsi M. Haldar, Mattia Quattrocelli

Dynamic Transition of Regulatory T Cells to Cytotoxic Phenotype Amid Systemic Inflammation in Graves' Ophthalmopathy

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Abstract

Graves' disease (GD) is an autoimmune condition that can progress to Graves' Ophthalmopathy (GO), leading to irreversible damage to orbital tissues and potential blindness. The pathogenic mechanism is not fully understood. In this study, we conducted single-cell multi-omics analyses on healthy individuals, GD patients without GO, newly diagnosed GO patients, and treated GO patients. Our findings revealed gradual systemic inflammation during GO progression, marked by overactivation of cytotoxic effector T cell subsets, and expansion of specific T cell receptor clones. Importantly, we observed a decline in the immunosuppressive function of activated regulatory T cells (aTreg) accompanied by a cytotoxic phenotypic transition. In vitro experiments revealed that dysfunction and transition of GO-autoreactive Treg were regulated by the yinyang1 (YY1) upon secondary stimulation of thyroid stimulating hormone receptor (TSHR) under inflammatory conditions. Furthermore, adoptive transfer experiments of GO mouse model confirmed infiltration of these cytotoxic Treg into the orbital lesion tissues. Notably, these cells were found to upregulate inflammation and promote pathogenic fibrosis of orbital fibroblasts (OFs). Our results revealed the dynamic changes in immune landscape during GO progression and provided novel insights into the instability and phenotypic transition of Treg, offering potential targets for therapeutic intervention and prevention of autoimmune diseases.

Authors

Zhong Liu, Shurui Ke, Zhuoxing Shi, Ming Zhou, Li Sun, Qihang Sun, Bing Xiao, Dongliang Wang, Yanjing Huang, Jinshan Lin, Huishi Wang, Qikai Zhang, Caineng Pan, Xuanwei Liang, Rongxin Chen, Zhen Mao, Xianchai Lin

Effects of SIPA1L1 on trabecular meshwork extracellular matrix protein accumulation and cellular phagocytosis in POAG

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Abstract

Accumulation of extracellular matrix (ECM) proteins in trabecular meshwork (TM), which leads to increased outflow resistance of aqueous humor and consequently high intraocular pressure, is a major cause of primary open-angle glaucoma (POAG). According to our preliminary research, the RapGAP protein superfamily member, signal-induced proliferation-associated 1-like 1 protein (SIPA1L1), which is involved in tissue fibrosis, may have an impact on POAG by influencing ECM metabolism of TM. This study aims to confirm these findings and identify effects and cellular mechanisms of SIPA1L1 on ECM changes and phagocytosis in human TM (HTM) cells. Our results showed that the expression of SIPA1L1 in HTM cells was significantly increased by TGFβ2 treatment in Label-free quantitative proteomics. The aqueous humor and TM cells concentration of SIPA1L1 in POAG patients was higher than that of control. In HTM cells, TGFβ2 increased expression of SIPA1L1 along with accumulation of ECM, RhoA and p-Cofilin1. The effects of TGFβ2 were reduced by si-SIPA1L1. TGFβ2 decreased HTM cell phagocytosis by polymerizing cytoskeletal actin filaments, while si-SIPA1L1 increased phagocytosis by disassembling actin filaments. Simultaneously, overexpressing SIPA1L1 alone exhibited comparable effects to that of TGFβ2. Our studies demonstrate that SIPA1L1 not only promotes the production of ECM, but also inhibits its removal by reducing phagocytosis. Targeting SIPA1L1 degradation may become a significant therapy for POAG.

Authors

Chenyu Xu, Jiahong Wei, Dan Song, Siyu Zhao, Mingmin Hou, Yuchen Fan, Li Guo, Hao Sun, Tao Guo

Disruption of mitochondrial electron transport impairs urinary concentration via AMPK-dependent suppression of aquaporin-2

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Abstract

Urinary concentration is an energy-dependent process that minimizes body water loss by increasing aquaporin-2 (AQP2) expression in collecting duct (CD) principal cells. To investigate the role of mitochondrial (mt) ATP production in renal water clearance, we disrupted mt electron transport in CD cells by targeting ubiquinone (Q) binding protein QPC (UQCRQ), a subunit of mt complex III essential for oxidative phosphorylation. QPC-deficient mice produced less concentrated urine than controls, both at baseline and after type 2 vasopressin receptor stimulation with desmopressin. Impaired urinary concentration in QPC-deficient mice was associated with reduced total AQP2 protein levels in CD tubules, while AQP2 phosphorylation and membrane trafficking remained unaffected. In cultured inner medullary CD cells treated with mt complex III inhibitor antimycin A, the reduction in AQP2 abundance was associated with activation of 5′ adenosine monophosphate-activated protein kinase (AMPK) and was reversed by treatment with AMPK inhibitor SBI-0206965. In summary, our studies demonstrated that the physiological regulation of AQP2 abundance in principal CD cells was dependent on mt electron transport. Furthermore, our data suggested that oxidative phosphorylation in CD cells was dispensable for maintaining water homeostasis under baseline conditions, but necessary for maximal stimulation of AQP2 expression and urinary concentration.

Authors

Joshua S. Carty, Ryoichi Bessho, Yvonne Zuchowski, Jonathan B. Trapani, Olena Davidoff, Hanako Kobayashi, Joseph T. Roland, Jason A. Watts, Andrew S. Terker, Fabian Bock, Juan Pablo Arroyo, Volker H. Haase