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P2RX7, an ionotropic receptor for extracellular adenosine triphosphate (ATP), is expressed on immune cells, including macrophages, monocytes, and dendritic cells and is upregulated on nonimmune cells following injury. P2RX7 plays a role in many biological processes, including production of proinflammatory cytokines such as interleukin (IL)‐1β via the canonical inflammasome pathway. P2RX7 has been shown to be important in inflammation and fibrosis and may also play a role in autoimmunity. We have developed and phenotyped a novel P2RX7 knockout (KO) inbred rat strain and, taking advantage of the human‐resembling unique histopathological features of rat models of glomerulonephritis, we induced three models of disease: nephrotoxic nephritis, experimental autoimmune glomerulonephritis, and experimental autoimmune vasculitis. We found that deletion of P2RX7 does not protect rats from models of experimental glomerulonephritis or the development of autoimmunity. Notably, treatment with A‐438079, a P2RX7 antagonist, was equally protective in WKY WT and P2RX7 KO rats, revealing its 'off‐target' properties. We identified a novel ATP/P2RX7/K+ efflux‐independent and caspase‐1/8‐dependent pathway for the production of IL‐1β in rat dendritic cells, which was absent in macrophages. Taken together, these results comprehensively establish that inflammation and autoimmunity in glomerulonephritis is independent of P2RX7 and reveals the off‐target properties of drugs previously known as selective P2RX7 antagonists. Rat mononuclear phagocytes may be able to utilise an 'alternative inflammasome' pathway to produce IL‐1β independently of P2RX7, which may account for the susceptibility of P2RX7 KO rats to inflammation and autoimmunity in glomerulonephritis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

It is well established that L-NAME, a generic NOS inhibitor, stimulates neurogenesis in the dentate gyrus of the adult rat and corticosterone reduces it. These experiments explore the interaction between L-NAME and corticosterone. L-NAME (50 mg/kg), as expected, increased proliferation, but also lowered plasma corticosterone levels. However, the stimulating action of L-NAME depends on the presence of rhythmic changes in plasma corticosterone, as it is abolished in rats treated with a subcutaneous implant of corticosterone, which flattens the diurnal rhythm. Adrenalectomized rats implanted with corticosterone also failed to respond to L-NAME. Giving them a single daily injection of corticosterone (2 mg/kg) in an attempt to replicate the diurnal rhythm restored the sensitivity of the progenitor cells to L-NAME. The mechanism for this result remains to be investigated. Excess corticosterone given by daily injection (40/mg/kg) reduced proliferation but did not alter the response to L-NAME, even though this occurred from a lower baseline. nNOS was demonstrable only in the inner (proliferative) layer of the dentate gyrus in control rats, and did not alter following excess corticosterone treatment. iNOS was detectable at low levels in control rats, but was increased markedly following corticosterone. eNOS was evident throughout the dentate gyrus, and also increased after corticosterone (particularly in the hilus). Aminoguanidine (100 mg/kg/day; an iNOS antagonist) significantly increased proliferation in corticosterone-treated rats (40 mg/kg/day) but not in controls without additional corticosterone, confirming that iNOS plays a role in corticosterone-regulated neurogenesis. Corticosterone may thus act on progenitor cells in part at least through increased nitric oxide (NO) formation. The effects of reduced NO on neurogenesis may rely on a dual mechanism: corresponding reductions in plasma corticosterone and increased induction of iNOS (and/or eNOS) within the dentate gyrus. The possibility that NO acts downstream of glucocorticoids in the dentate gyrus is suggested.Neuropsychopharmacology (2007) 32, 493–504. doi:10.1038/sj.npp.1301245; published online 1 November 2006 [ABSTRACT FROM AUTHOR]

Background: B cell depletion therapy (BCDT) using rituximab, a monoclonal antibody targeting CD20, was first used for systemic lupus erythematosus (SLE) in 2000 for patients refractory to conventional immunosuppressants. Although the successful use of BCDT has been reported in open label studies randomized controlled trials in SLE have not met their endpoints. SLE is a heterogeneous disease and it is possible that variation in response to BCDT might be due to differences in the rate of B cell repopulation and/or serological and cellular factors in treated patients. The aim of this study was to correlate the repopulation of B cells with disease relapse after BCDT and to identify any differences in B cell numbers and phenotype between patients with active disease according to other disease parameters.Methods: Fifty-nine patients with refractory SLE treated with BCDT using a combination of rituximab, cyclophosphamide and methylprednisolone were followed up for a minimum of 18 months or until relapse if this occurred within 18 months. Patients were assessed with the ‘classic' British Isles Lupus Assessment Group (BILAG) activity index. Relapse was defined as a new BILAG ‘A’ or two new ‘B’s in any organ system. Anti-dsDNA antibody titres, complement and leukocyte numbers were measured at baseline and relapse. B cell phenotypes were measured at relapse by flow cytometry using the markers CD19, IgD and CD27.Results: The median time to relapse following BCDT was 16 months. During repopulation B cell numbers remained below baseline numbers for up to 9 months (p < 0.01). B cell numbers (normal range 0.11-0.50 x109 cells/L) increased more rapidly in patients that relapsed (within 18 months) compared to those that remained in remission (p < 0.01). At relapse, B cell numbers were lower than at baseline (p < 0.05). Patients that relapsed with very low B cell numbers (<0.01x109 cells/L) had the lowest B cell numbers at baseline (P < 0.05) and the highest anti-dsDNA antibody titres (normal range 0-50 IU/mL) at relapse (P < 0.05). Relapse with high anti-dsDNA antibody titres (>100 IU/mL) was associated with an increased percentage of IgD-CD27hi switched plasmablasts (p < 0.05) whereas relapse with low anti-dsDNA antibody titres was associated with an increased percentage of IgD-CD27- memory B cells (p < 0.05).Conclusions: Whilst clinical trials have not confirmed the reported benefit of BCDT in SLE this study shows that early relapse was associated with faster rates of B cell repopulation despite similar levels of depletion. The number of B cells and the B cell phenotype found at relapse differed according to the anti-dsDNA antibody titres. This data suggest that different pathologies might exist in patients with low anti-dsDNA antibody titres compared to those with high titres, possibly governed by specific B cell subsets. Future clinical trials in SLE should take into account serological and cellular variation between patients.Disclosure statement: D.I. has received honoraria from Roche, Vifor, GlaxoSmithKline, Teva and Merck Serono; these were donated to a local arthritis charity. All other authors have declared no conflicts of interest. [ABSTRACT FROM PUBLISHER]

Background: The acute and long-term effects of severe acute respiratory syndrome coronavirus 2 infection in individuals with GN are still unclear. To address this relevant issue, we created the International Registry of COVID-19 infection in GN., Methods: We collected serial information on kidney-related and -unrelated outcomes from 125 GN patients (63 hospitalized and 62 outpatients) and 83 non-GN hospitalized patients with coronavirus disease 2019 (COVID-19) and a median follow-up period of 6.4 (interquartile range 2.3-9.6) months after diagnosis. We used logistic regression for the analyses of clinical outcomes and linear mixed models for the longitudinal analyses of eGFR. All multiple regression models were adjusted for age, sex, ethnicity, and renin-angiotensin-aldosterone system inhibitor use., Results: After adjustment for pre-COVID-19 eGFR and other confounders, mortality and AKI did not differ between GN patients and controls (adjusted odds ratio for AKI=1.28; 95% confidence interval [CI], 0.46 to 3.60; P =0.64). The main predictor of AKI was pre-COVID-19 eGFR (adjusted odds ratio per 1 SD unit decrease in eGFR=3.04; 95% CI, 1.76 to 5.28; P <0.001). GN patients developing AKI were less likely to recover pre-COVID-19 eGFR compared with controls (adjusted 6-month post-COVID-19 eGFR=0.41; 95% CI, 0.25 to 0.56; times pre-COVID-19 eGFR). Shorter duration of GN diagnosis, higher pre-COVID-19 proteinuria, and diagnosis of focal segmental glomerulosclerosis or minimal change disease were associated with a lower post-COVID-19 eGFR., Conclusions: Pre-COVID-19 eGFR is the main risk factor for AKI regardless of GN diagnosis. However, GN patients are at higher risk of impaired eGFR recovery after COVID-19-associated AKI. These patients (especially those with high baseline proteinuria or a diagnosis of focal segmental glomerulosclerosis or minimal change disease) should be closely monitored not only during the acute phases of COVID-19 but also after its resolution., Competing Interests: O. Bestard reports patents and inventions with Oxford Immunotec and is associate editor of Transplant International and Frontiers in Immunology. A. Bruchfeld reports consultancy agreements with AstraZeneca, Chemocentryx, Fresenius, and Merck; a research grant from AstraZeneca; honoraria from Bayer, Chemocentryx, Fresenius, Merck, and Vifor; and is a member of the ERA-EDTA scientific advisory board 2018–2024, chair of the ERA-EDTA Immunonephrology Working Group, and vice-chair of the Swedish Renal Fund. G. Comai reports honoraria from Alexion, Astellas, and Novartis. P. Cravedi reports honoraria as an advisor for Chinook Therapeutics and is associate editor for the Journal of Nephrology and the American Journal of Transplantation. G. Fernandez Juarez reports research funding from Instituto Salud Calos III and honoraria from Alexion and GSK. E. Fiaccadori is on the editorial board of the Journal of Nephrology and Blood Purification and is a member of the Italian Society of Nephrology and the European Society of Parenteral and Enteral Nutrition. O. Flossmann reports consultancy agreements with Vifor Pharma has other interests/relationships with the British Medical Association, European Vasculitis Society, Renal Association (UK), Royal College of Physicians London, and UK Ireland Vasculitis Society. C. García-Carro reports consultancy agreements with Astellas, AstraZeneca, Boehringer Ingelheim Lilly, Esteve, Novartis and Baxter, Novo Nordisk, and Otsuka; honoraria from Astellas, AstraZeneca, Boehringer Ingelheim Lilly, Esteve, Novartis and Baxter, Novo Nordisk, and Otsuka; and is a scientific advisor for or member of AstraZeneca, Boehringer Ingelheim Lilly, Mundipharma, and Novo Nordisk. M. Griffith reports honoraria from Retrophin’s advisory board. A. J. Hamilton is on the editorial board of the Journal of Kidney Care and is a member of the SONG-Kids Life Participation Expert Working Group. T. Leach reports honoraria from Janssen for conference attendance in 2012 and is a scientific advisor to the National Institute for Health and Care Excellence. L. Lightstone reports consultancy agreements with Achillion, Alexion, AstraZeneca, Aurinia, BMS, GSK, Kezar, Novartis, Pfizer, and Roche; honoraria from Alexion, AstraZeneca, BMS, GSK, and Pfizer; is a scientific advisor or member of EU Exec Lupus Nephritis Trials Network; is on the advisory board of Nature Reviews Nephrology; participates in a speakers’ bureau for Alexion and GSK; is a trustee of Kidney Research UK 2018–2022; is an executive member of the International Society of Nephrology 2021–2023; is deputy chair of Western Regional Board of the International Society of Nephrology; and is a clinical expert representing the Renal Association response to NICE on STA for belimumab in lupus 2020–2021. U. Maggiore reports consultancy agreements with Biotest, Chiesi, GSK, Hansa, Novartis, Sandoz, and Takeda. J. Manrique is a scientific advisor for or member of AstraZeneca, Boehringer, and Viphor Pharma. E. Morales reports consultancy agreements with Alexion, Celgene, Viphor Fresenius, and Vifor Pharma. J.A. Niño-Cruz reports research funding from Pfizer Scientific Institute and participates in a speakers’ bureau for Takeda and Roche. A. Ortiz reports consultancy agreements with Retrophin and Sanofi Genzyme; research funding from AstraZeneca, Mundipharma, and Sanofi Genzyme; honoraria from Advicciene, Alexion, Amgen, Amicus, Astellas, AstraZeneca, Bayer, Chiesi, Fresenius Medical Care, Idorsia, Kyowa Kirin, Menarini, Otsuka, Sanofi Genzyme, and Vifor Fresenius Medical Care Renal Pharma; is a member of the Spanish Society of Nephrology; is editor-in-chief of the Clinical Kidney Journal; is on the editorial boards of the Journal of Nephrology, Journal of the American Society of Nephrology, and Peritoneal Dialysis International; is a member of SOMANE and ERA Councils; is on the board of directors for IIS-Fundacion Jimenez Diaz UAM; is on the scientific advisory board of the Dutch Kidney Foundation; honoraria listed above are for speaker engagements: Advicciene, Alexion, Astellas, AstraZeneca, Amicus, Amgen, Bayer, Chiesi, Fresenius Medical Care, Idorsia, Kyowa Kirin, Menarini, Otsuka, Sanofi Genzyme, and Vifor Fresenius Medical Care Renal Pharma. S. Sinha reports consultancy agreements with Sanifit; research funding from Amgen, AstraZeneca, and Ethicon; and honoraria from AstraZeneca, Bayer, Napp Pharmaceuticals, Novartis, and Sanofi Genzyme. M.F. Slon-Roblero reports consultancy agreements with Baxter, Fresenius, and Nipro; and honoraria from Baxter, Fresenius, and Nipro. M.J. Soler reports consultancy agreements with AstraZeneca, Bayer, Boehringer, Esteve, Jansen, Mundipharma, Novo Nordisk, Travere, and ICU; research funding from Abbvie and Boehringer; honoraria from AstraZeneca, Boehringer, Esteve, FMC, Jansen, ICU Medical, Mundipharma, Novo Nordisk, Otsuka, and Travere; patents and inventions: U691ES00; is a scientific advisor for or member of BMC Nephrology and Clinical Kidney Journal; is a former member of ERA-EDTA Council; participates in a speakers’ bureau for AstraZeneca, Bayer, Boehringer, Esteve, FMC, Jansen, Mundipharma, Novo Nordisk, and Vifor; is a member of the Sociedad Española de Nefrología and Sociedad Catalana de Nefrologia; and is elected editor-in-chief of the Clinical Kidney Journal. All remaining authors have nothing to disclose., (Copyright © 2022 by the American Society of Nephrology.)