Biology subjects

Butter, L.

Publications and source records attributed to Butter, L..

6 recordsLinked to original sources

bioRxiv2025

Levamisole-Mediated Suppression of B-Cell Proliferation and Antibody Production Reveals Mechanistic Insights into Idiopathic Nephrotic Syndrome Therapy

Levamisole (LMS) is a small imidazole derivative with immunomodulatory properties. Despite its longstanding clinical use in Idiopathic Nephrotic Syndrome (INS), the mechanisms underlying its immune-regulating effects remain poorly defined. In this study, we investigated the in vitro effects of LMS treatment on human B-cells, and in patients included from the LEARNS (LEvamisole as Adjuvant therapy to Reduce relapses of Nephrotic Syndrome) clinical trial. In vitro experiments showed that LMS directly suppresses activation and proliferation in both T-cell dependent and T-cell independent stimulated B-cells, without inducing cytotoxicity. In agreement, transcriptomic profiling demonstrated downregulation of cell cycle-associated genes and genes involved in immunoglobulin synthesis, while genes involved in terminal B-cell differentiation were upregulated, including SLAMF7. Consistently, LMS treatment decreased immunoglobulin expression and secretion while simultaneously inducing the expression of factors associated with a more terminal B-cell phenotype (CD138/CD319). Flowcytometry analysis of blood samples from LMS-treated INS patients revealed reduced circulating B-cell counts. Collectively, these data suggest that LMS acts as a potent modulator of B-cell function that inhibits proliferation and immunoglobulin synthesis, providing mechanistic support for its therapeutic efficacy in INS management.

immunology↗

bioRxiv2025

NNMT promotes tubular senescence and fibrosis in chronic kidney disease

Chronic kidney disease (CKD) is a major global health issue, projected to become the fifth leading cause of mortality by 2040. Renal tubular cell senescence is a key driver of kidney fibrosis, the final manifestation of CKD. However, current treatment strategies, do not target senescent cells, as the underlying mechanisms driving this dysfunctional phenotype remain poorly described. Here, we identify nicotinamide-N-methyltransferase (NNMT), as a critical mediator of tubular senescence and fibrosis in CKD. Using human RNAseq profiles of CKD, we show that NNMT expression in the renal tubulointerstitium is strongly associated with CKD pathology and transcriptional signatures of cellular senescence. In human diabetic kidney disease biopsies, NNMT levels correlate with the senescence marker p21, kidney function decline, and fibrosis. Spatial transcriptomics further highlights that NNMT-positive tubules are senescent, fibrotic, and surrounded by a pro-inflammatory microenvironment. Preclinical models of early-stage CKD, show upregulation of NNMT and association with senescence. Overexpression of NNMT in TGF-{beta}-stimulated tubular epithelial cells promotes senescence and partial epithelial-to-mesenchymal transition (EMT), while inhibition of NNMT in kidney cells and organoids is protective. Altogether, we identify NNMT as a novel therapeutic target in the early stages of CKD with the potential to reduce tubular senescence, fibrosis and significantly slow disease progression.

cell biology↗

bioRxiv2023

Treatment with a selective histone deacetylase (HDAC) 1 and 2 inhibitor in aged mice rejuvenates multiple organ systems

The process of aging increases the risk of developing age-related diseases, which come at great societal healthcare costs and suffering to individuals. Meanwhile, targeting the basic mechanisms of aging can reduce the risk of developing age-related diseases during aging, essentially resulting in a healthy aging process. Multiple aging pathways exist, which over past decades have systematically been confirmed through gene knockout or overexpression studies in mammals and the ability to increase healthy lifespan. In this work, we perform transcriptome-based drug screening to identify small molecules that mimic the transcriptional profiles of long-lived genetic interventions in mammals. We identify one small molecule whose transcriptional effects mimic diverse known genetic longevity interventions: compound 60 (Cmpd60), which is a selective inhibitor of histone deacetylase 1 (HDAC1) and 2 (HDAC2). In line with this, in a battery of molecular, phenotypic, and bioinformatic analyses, in multiple disease cell and animal models, we find that Cmpd60 treatment rejuvenates multiple organ systems. These included the kidney, brain, and heart. In renal aging, Cmpd60 reduced partial epithelial-mesenchymal transition (EMT) in vitro and decreased fibrosis in vivo. For the aging brain, Cmpd60 reduced dementia-related gene expression in vivo, effects that were recapitulated when treating the APPSWE-1349 Alzheimer mouse. In cardiac aging, Cmpd60 treatment activated favorable developmental gene expression in vivo and in line with this, improved ventricular cardiomyocyte contraction and relaxation in a cell model of cardiac hypertrophy. Our work establishes that a systemic, two-week treatment with an HDAC1/2 inhibitor serves as a multi-tissue, healthy aging intervention in mammals. This holds potential for translation towards therapeutics that promote healthy aging in humans.

pathology↗

bioRxiv2023

Air Pollution Aggravates Renal Ischemia-Reperfusion-Induced Acute Kidney Injury

Chronic kidney disease (CKD) has emerged as a significant global public health concern. Recent epidemiological studies have highlighted the link between exposure to fine particulate matter (PM2.5) and declined renal function. PM2.5 exerts its harmful effects on various organs through oxidative stress and inflammation. Acute kidney injury (AKI) resulting from ischemia reperfusion injury (IRI) involves similar biological processes involved in PM2.5 toxicity and is a known risk factor for CKD. The objective of this study was to investigate the impact of PM2.5 exposure on IRI-induced AKI. Mice were exposed to PM2.5 or filtered air for 12 weeks before IRI, and were euthanized 48h after IRI. Animals exposed to PM2.5 and IRI exhibited reduced glomerular filtration and impaired urine concentration ability. Moreover, they showed elevated tubular damage markers NGAL and KIM-1, along with significant tubular necrosis. PM2.5 exposure exacerbated local innate immune activation, leading to an increased infiltration of Ly6G+ granulocytes and F480+ macrophages in the kidney. This, in turn, contributed to heightened renal senescence markers and myofibroblast infiltration. Collectively, our findings suggest that AKI-induced hampered tubular function is worsened by PM2.5, leading to reduced resilience to stress, activation of aging mechanisms and early hallmarks of fibrosis. Decreasing PM2.5 and implementing preventive strategies can improve AKI patients outcome and prevent AKI progression.

pathology↗

bioRxiv2023

Levamisole suppresses activation and proliferation of human T cells by the induction of a p53-dependent DNA damage response

Levamisole (LMS) is a small molecule used in the treatment of idiopathic nephrotic syndrome (INS). The pathogenesis of INS remains unknown, but most evidence points towards an immunological basis of the disease. Recently, LMS has been shown to increase the relapse-free survival in INS patients treated in combination with corticosteroids with relatively few side effects. While LMS has been hypothesized to exert an immunomodulatory effect, its mechanism of action remains unknown. To provide insight into the working mechanism of LMS, we studied its immunomodulatory activity on in vitro activated human T cells. We show here that treatment with LMS decreased activation and proliferation of human CD4+ and CD8+ T cells. In addition, production of T cell activation-associated cytokines such as IL-2, TNF- and IFN-{gamma} were reduced upon LMS treatment, whereas IL-4 and IL-13 production was increased. Gene expression profiling confirmed the suppressive effects of LMS on proliferation as numerous genes involved in cell cycle progression were downregulated. Furthermore, genes associated with p53 activation and cell cycle arrest were upregulated by LMS. In agreement, LMS treatment resulted in p53 phosphorylation and increased expression of the p53 target gene FAS. Accordingly, LMS sensitized activated T cells for Fas-mediated apoptosis. Cell cycle analysis showed that LMS induced a mid-S phase arrest indicating the activation of a replication stress-associated checkpoint. In support, LMS treatment resulted in {gamma}H2AX-foci formation and phosphorylation of CHK1. Our findings indicate that LMS acts as an immunosuppressive drug that directly affects the activation and proliferation of human T cells by induction of DNA damage and the activation of a p53-dependent DNA damage response.

immunology↗

bioRxiv2019

Dual role of protease activated receptor 4 in acute kidney injury: contributing to renal injury and inflammation, while maintaining the renal filtration barrier upon acute renal ischemia reperfusion injury

Ischemia reperfusion (I/R) injury triggers the activation of coagulation and inflammation processes involved in the pathophysiology of acute kidney injury (AKI). Coagulation proteases upregulated upon renal I/R injury activate protease activated receptors (PARs), which form an important molecular link between inflammation and coagulation. PAR4 is the major thrombin receptor on mouse platelets, and the only PAR that is expressed on both human and murine platelets. In addition, PAR4 is expressed on other cells including podocytes. We here sought to determine the contribution of PAR4 in the host response to renal I/R injury. Hence, we subjected PAR4 knockout and wild-type mice to renal I/R injury. PAR4 knockout mice exhibited an increased tolerance to renal tubular necrosis and showed a decreased neutrophil influx in response to renal I/R, independent from platelet PAR4. On the other hand, PAR4 deficiency resulted in albumin cast formation in peritubular capillaries and showed a tendency towards albuminuria. Transmission Electron Microscopy revealed an increase in podocyte foot process effacement. Our findings suggest that PAR4 contributes to renal injury likely through facilitating neutrophil migration, independent from platelet PAR4. In addition, PAR4 fulfils an important function in the maintenance of podocyte integrity following renal I/R insult. Subsequently, loss of PAR4 results in albuminuria.

immunology↗