Appadurai et al. report a critical role for the sialyltransferase ST6GalNAc-I in immunosuppression and angiogenesis in non–small cell lung cancer (NSCLC) via sialyation of the glycoproteins NECTIN2 and MUC5AC. The cover image shows the distribution of MUC5AC in NSCLC tissue.
Germinal centre (GC) B cells are pivotal in establishing a robust humoral immune response and long-term serological immunity while maintaining antibody self-tolerance. GC B cells rely on autophagy for antigen presentation and homeostatic maintenance. However, these functions, primarily associated with the light zone, cannot explain the spatiotemporal autophagy upregulation in the dark zone of GCs. Here, we define a functional mechanism controlling chromatin accessibility in GC B cells during their dark zone transition. This mechanism links autophagy and nuclear Lamin B1 dynamics with their downstream effects, including somatic hypermutation and antibody affinity maturation. Moreover, the autophagy-Lamin B1 axis is highly active in the aberrant ectopic germinal centres in the salivary glands of Sjogren’s disease, defining its role in autoimmunity.
Marta C Sallan, Filip Filipsky, Christina H. Shi, Elena Pontarini, Manuela Terranova-Barberio, Gordon Beattie, Andrew Clear, Michele Bombardieri, Kevin Y. Yip, Dinis Parente Calado, Mark S. Cragg, Sonya James, Matthew J. Carter, Jessica Okosun, John G. Gribben, Tanya Klymenko, Andrejs Braun
BACKGROUND. Treatment of tubo-ovarian high-grade serous carcinoma (HGSC) includes cytoreductive surgery, platinum-based chemotherapy, and often poly (ADP-ribose) polymerase (PARP) inhibitors. While homologous recombination (HR)-deficiency is a well-established predictor of therapy sensitivity, over 50% of HR-proficient HGSC also exhibit sensitivity. Currently, there are no biomarkers to identify which HR-proficient HGSCs will be sensitive to standard-of-care therapy. Replication stress may serve as a key determinant of response. METHODS. We evaluated phospho-RPA2-T21 (pRPA2) foci via immunofluorescence as a biomarker of replication stress in formalin-fixed, paraffin-embedded HGSC samples collected at diagnosis from patients treated with platinum chemotherapy (discovery cohort: n=31, validation cohort: n=244) or PARP inhibitors (n=63). Recurrent HGSCs (n=38) were also analyzed. pRPA2 score was calculated using automated imaging analysis. RESULTS. Samples were defined as pRPA2-High if >16% of cells had ≥2 pRPA2 foci on automated analysis. In the discovery cohort, HR-proficient, pRPA2-High HGSCs demonstrated significantly higher rates of a chemotherapy response score of 3 to platinum chemotherapy than HR-proficient, pRPA2-Low HGSCs. In the validation cohort, patients with HR-proficient, pRPA2-High HGSCs had significantly longer survival after platinum treatment than those with HR-proficient, pRPA2-Low HGSCs. Additionally, the pRPA2 assay effectively predicted survival outcomes in patients treated with PARP inhibitors and in recurrent HGSC samples. CONCLUSION. Our study underscores the importance of considering replication stress marker, such as pRPA2, alongside HR status in therapeutic planning. This approach has the potential to increase the number of patients receiving effective therapy while reducing unnecessary toxicity.
Angela Schab, Amanda Compadre, Rebecca Drexler, Megan Loeb, Kevin Rodriguez, Joshua Brill, Shariska Harrington, Carmen Sandoval, Brooke Sanders, Lindsay Kuroki, Carolyn McCourt, Andrea R. Hagemann, Premal Thaker, David Mutch, Matthew Powell, Violeta Serra, Ian S. Hagemann, Ann E. Walts, Beth Y. Karlan, Sandra Orsulic, Katherine Fuh, Lulu Sun, Priyanka Verma, Elena Lomonosova, Peinan Zhao, Dineo Khabele, Mary M. Mullen
Mitral valve prolapse is often benign but progression to mitral regurgitation may require invasive intervention and there is no specific medical therapy. An association of mitral valve prolapse with Marfan syndrome resulting from pathogenic FBN1 variants supports the use of hypomorphic fibrillin-1 mgR mice to investigate mechanisms and therapy for mitral valve disease. mgR mice developed severe myxomatous mitral valve degeneration with mitral regurgitation by 12 weeks of age. Persistent activation of TGF-β and mTOR signaling along with macrophage recruitment preceded histological changes at 4 weeks of age. Short-term mTOR inhibition with rapamycin from 4 to 5 weeks of age prevented TGF-β overactivity and leukocytic infiltrates, while long-term inhibition of mTOR or TGF-β signaling from 4 to 12 weeks of age rescued mitral valve leaflet degeneration. Transcriptomic analysis identified integrins as key receptors in signaling interactions and serologic neutralization of integrin signaling or a chimeric integrin receptor altering signaling prevented mTOR activation. We confirmed increased mTOR signaling and a conserved transcriptome signature in human specimens of sporadic mitral valve prolapse. Thus, mTOR activation from abnormal integrin-dependent cell-matrix interactions drives TGF-β overactivity and myxomatous mitral valve degeneration, and mTOR inhibition may prevent disease progression of mitral valve prolapse.
Fu Gao, Qixin Chen, Makoto Mori, Sufang Li, Giovanni Ferrari, Markus Krane, Rong Fan, George Tellides, Yang Liu, Arnar Geirsson
Defects in the early events of insulin biosynthesis, including inefficient preproinsulin (PPI) translocation across the membrane of the endoplasmic reticulum (ER) and proinsulin (PI) misfolding in the ER, can cause diabetes. Cellular machineries involved in these events remain poorly defined. Gene encoding TRanslocon-Associated Protein alpha (TRAPα) shows linkage to glycemic control in humans, although their pathophysiological role remains unknown. Here we found that β-cell specific TRAPα knockout (TRAPα-βKO) mice fed with chow diet or high fat diet (HFD) exhibit decreased circulating insulin, with age- and diet-related glucose intolerance. Multiple independent approaches revealed that TRAPα-βKO not only causes inefficient PPI translocation, but also leads to PI misfolding and ER stress, selectively limiting PI ER export and β-cell compensatory potential. Importantly, decreased TRAPα expression was evident in islets of wild-type mice fed with high fat diet and in patients with type 2 diabetes (T2D). Furthermore, TRAPα expression was positively correlated with insulin content in human islet β cells, and decreased TRAPα was associated with PI maturation defects in T2D islets. Together, these data demonstrate that TRAPα deficiency in pancreatic β-cells impairs PPI translocation, PI folding, insulin production, and glucose homeostasis, contributing to its genetic linkage to T2D.
Xin Li, Jingxin Hu, Yumeng Huang, Hai Zhang, Ning Xu, Yang Liu, Xuan Liu, Yuanyuan Ye, Xinxin Zhang, Xiaoxi Xu, Yuxin Fan, Ziyue Zhang, Weiping J. Zhang, Shusen Wang, Wenli Feng, Peter Arvan, Ming Liu
BACKGROUND. Kidney stone disease (KSD) affects ~10% of adults, is heritable, and associated with mineral metabolic abnormalities. METHODS. Genetic variants and pathways increasing KSD risk via calcium and phosphate homeostasis were ascertained using genome-wide association analyses, region-specific Mendelian randomization (MR), and genetic colocalization. Utility of pathway modulation was estimated via drug-target MR, and effects of variants on calcium-sensing receptor (CaSR)-signaling characterized. RESULTS. Seventy-nine independent KSD-associated genetic signals at 71 loci were identified. MR identified three loci affecting KSD risk via increased serum calcium or decreased serum phosphate concentrations (odds ratios for genomic regions=4.30, 11.42, and 13.83 per 1 standard deviation alteration; p<5.6x10-10). Colocalization analyses defined putative, non-coding KSD-causing variants estimated to account for 11-19% of KSD cases in proximity to diacylglycerol kinase delta (DGKD), a CaSR-signalling partner; solute carrier family 34 member 1 (SLC34A1), a renal sodium-phosphate transporter; and cytochrome P450 family 24 subfamily A member 1 (CYP24A1), which degrades 1,25-dihydroxyvitamin D. Drug- target MR indicated that reducing serum calcium by 0.08mmol/L via CASR, DGKD, or CYP24A1, or increasing serum phosphate by 0.16mmol/L via SLC34A1 may reduce KSD relative risk by up to 90%. Furthermore, reduced DGKδ expression and KSD-associated DGKD missense variants impaired CaSR-signal transduction in vitro, which was ameliorated by cinacalcet, a positive CaSR-allosteric modulator. CONCLUSION. DGKD-, SLC34A1-, and CYP24A1-associated variants linked to reduced CaSR-signal transduction, increased urinary phosphate excretion, and impaired 1,25-dihydroxyvitamin D inactivation, respectively, are common causes of KSD. Genotyping patients with KSD may facilitate personalised KSD-risk stratification and targeted pharmacomodulation of associated pathways to prevent KSD.
Catherine E. Lovegrove, Michelle Goldsworthy, Jeremy Haley, Diane Smelser, Caroline Gorvin, Fadil M. Hannan, Anubha Mahajan, Mohnish Suri, Omid Sadeghi-Alavijeh, Shabbir H. Moochhala, Daniel P. Gale, David Carey, Michael V. Holmes, Dominic Furniss, Rajesh V. Thakker, Sarah A. Howles
The complement system executes an evolutionarily ancient innate immune response with important roles in many human diseases, including a variety of conditions involving the kidney, autoimmune disorders, age-related macular degeneration, and more. This series of reviews, curated by Dr. Claudia Kemper, highlights the latest discoveries in complement biology and examines ongoing efforts to target complement therapeutically. From the relatively newly uncovered functions of intracellular complement (complosome) to the complexities involved in using animal models of complementopathies, these reviews convey the challenges of studying complement and developing complement-targeted therapeutics as well as call attention to recent findings that supply momentum to the field.
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