Biology subjects

Tsang, Y. P.

Publications and source records attributed to Tsang, Y. P..

3 recordsLinked to original sources

bioRxiv2026

Voclosporin Preserves Mitochondrial Function Compared With Cyclosporine A in Perfused Human Proximal Tubule Microphysiological Systems

Key PointsO_LIPerfused human kidney MPS revealed CsA-associated sublethal tubular stress that was not detected by conventional 2D viability assays or by KIM-1 release in 3D MPS. C_LIO_LIAt matched exposure, VCS preserved mitochondria and activated ER chaperones and iron detoxification, with no p21 arrest compared to CsA. C_LIO_LIMechanistic separation supports VCSs nephroprotection potential and early mechanism-based biomarkers to guide CNI choice. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/737071v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@c38ab8org.highwire.dtl.DTLVardef@1c8638forg.highwire.dtl.DTLVardef@100485aorg.highwire.dtl.DTLVardef@18e3d70_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG BackgroundCalcineurin inhibitors (CNIs) are indispensable for transplantation immunosuppression, yet cyclosporine A (CsA) produces renal toxicity. Voclosporin (VCS), a CsA analog, is proposed to be less nephrotoxic, but mechanisms remain unclear. MethodsPrimary human proximal tubule epithelial cells (PTECs) were exposed to CsA or VCS in 2D monolayers and perfused 3D kidney microphysiological system (MPS). Viability was assessed in 2D cultures by MTS, mitochondrial membrane potential ({Delta}{Psi}m) by TMRM flow cytometry, and soluble injury and inflammatory biomarkers in MPS effluents by ELISA and MSD multiplex assays. RNA sequencing of 3D-cultured PTECs was used to identify differentially expressed genes and pathways. ResultsIn 2D PTECs, neither drug reduced viability. In 3D MPS effluents, KIM-1 did not distinguish CsA from VCS, whereas the MSD biomarker panel showed larger aggregate deviation with CsA. Confocal tomography showed CsA-associated mitochondrial fragmentation, whereas VCS preserved reticular mitochondrial architecture. TMRM flow cytometry showed a treatment-dependent difference in TMRM-positive cells, with VCS yielding the highest TMRM-positive fraction and exceeding CsA, supporting preservation of {Delta}{Psi}m relative to CsA. RNA-seq identified 1188 CsA-specific and 185 VCS-specific differentially expressed genes, with 304 shared. Pathway analysis indicated CsA enrichment of unfolded protein response (UPR) and endoplasmic reticulum (ER) stress, p21-associated G2/M checkpoint arrest, and transcriptional signatures consistent with ferroptosis priming, while VCS mainly induced ER chaperone and ER-associated degradation gene programs without activating canonical UPR sensors and showed limited cell-cycle suppression. ConclusionsA physiologically relevant 3D kidney MPS revealed sublethal tubular stress from CsA that is masked in 2D culture, including mitochondrial depolarization, proteostatic stress, and ferroptosis priming. At matched exposure, VCS preserved mitochondrial function and proteostasis while eliciting a narrower, adaptive ER quality control response. These data support VCS as a nephron-sparing immunosuppressant and 3D MPS as a mechanism-based platform for evaluating renal safety of drugs and nominating early sub-lethal tubular injury biomarkers.

pharmacology and toxicology↗

bioRxiv2026

Cortisol Drives Pregnancy-Associated Induction of Hepatic OAT2, NTCP, and OCT1 in HepaRG cells Through GR-, HNF1α-, and HNF4α-Dependent Signaling

Pregnancy induces or represses hepatic drug metabolism. Whether pregnancy affects hepatic drug transport is unexplored. We previously showed that a cocktail of pregnancy-related hormones (PRHC) induces mRNA expression and activity of sodium/taurocholate cotransporting polypeptide (NTCP), organic anion transporter 2 (OAT2), and organic cation transporter 1 (OCT1, mRNA only) in differentiated HepaRG cells. Here, using HepaRG cells, we identified cortisol as the hormone primarily responsible for this induction and explored the underlying mechanisms. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9-mediated knockdown studies in HepaRG cells showed that the glucocorticoid receptor (GR) is the primary mediator of this response. GR knockdown markedly attenuated cortisol-induced NTCP, OAT2, and OCT1 mRNA expression and activity. Cortisol also induced the mRNA expression of regulatory factors, including pregnane X receptor (PXR), constitutive androstane receptor (CAR), and hepatocyte nuclear factor (HNF) 4 alpha (HNF4). HNF4 knockdown selectively attenuated OAT2 and OCT1 induction, whereas HNF1 knockdown enhanced NTCP induction, attenuated OCT1 induction, and reduced basal organic anion transporting polypeptide 1B1 (OATP1B1) expression. In contrast, knockdown of CAR or PXR did not significantly alter cortisol-mediated transporter regulation. These data identify cortisol as the principal PRH driving regulation of the hepatic OAT2, NTCP, and OCT1 in HepaRG cells and indicate that this response is mediated primarily by GR, with selective downstream contributions from HNF4 and HNF1. These findings provide mechanistic insights into pregnancy-associated changes in hepatic transporter-mediated drug disposition, including when antenatal corticosteroids are administered to pregnant women to prevent respiratory distress syndrome in their prematurely born infants. Significance StatementThe extent and mechanisms by which pregnancy-related hormones regulate hepatic uptake transporters remain poorly defined. This study identifies cortisol as the principal pregnancy-related hormone driving NTCP, OAT2, and OCT1 induction in HepaRG cells and shows that this response is mediated primarily through GR, with transporter-specific contributions from HNF4 and HNF1.

pharmacology and toxicology↗

bioRxiv2025

Regulation of Renal Transporters by Pro-inflammatory Cytokines in Human Proximal Tubular Epithelial Cells: Identification of the Perpetrator and Mechanisms

IntroductionInfection and inflammation elevate circulating pro-inflammatory cytokines that can affect renal drug clearance. Accordingly, we sought to (i) quantify the extent of modulation of renal drug-metabolizing enzymes and transporters (DMETs) by cytokines and (ii) identify the mechanism(s) underlying these effects. MethodsFresh primary human proximal tubular epithelial cells (PTECs) were cultured on extracellular matrix-coated Transwells. PTECs were exposed every 24 h, for 48 h, to IL-6, IL-1{beta}, TNF-, IFN-{gamma}, IL-4, or IL-10 (0.1 or 1 ng/mL), individually or as a cocktail. mRNA expression of 25 renal DMETs was quantified by RT-qPCR. Individual activity of OAT1-4, OCT2, and OCTN1 was measured. To determine mechanisms of these effects, selective MAPK/NF-{kappa}B inhibitors (ERK [PD98059], p38MAPK [SB203580], JNK [SP600125], and NF-{kappa}B [PDTC]), individually or as a cocktail, were used. IL-6, soluble IL-6 receptor (sIL-6R), and IL-6 + sIL-6R were used to probe endogenous/exogenous IL-6 classic versus trans-signaling. ResultsIL-1{beta} was the predominant modulator, downregulating mRNA expression of OAT1-3, OCT2, OAT4, MATE2-K, MRP2, and OATP4C1, and upregulating mRNA expression of OCTN1 and MRP3. TNF- downregulated OAT1-3 mRNA expression to an extent similar to IL-1{beta}, but did not affect other transporters. Activity changes for the major uptake transporters mirrored mRNA directionality. MAPK/NF-{kappa}B blockade by the inhibitor cocktail reduced IL-6 secretion while completely reversing the IL-1{beta}-driven downregulation of OAT1-3 mRNA. JNK inhibition alone restored OAT1/3 mRNA. Inhibition of p38MAPK blunted OAT2 mRNA downregulation. OCTN1 mRNA induction required NF-{kappa}B. Downregulation of OAT4/OCT2 mRNA was largely MAPK/NF-{kappa}B-independent. IL-6 alone, sIL-6R alone, or IL-6 + sIL-6R did not reproduce IL-1{beta}-driven changes in transporter mRNA. ConclusionsIL-1{beta} is the principal driver of cytokine-mediated regulation of human renal transporters in PTECs via JNK/p38MAPK/NF-{kappa}B nodes. These mechanistic, exposure-verified data provide inputs for physiologically based pharmacokinetic predictions of renal secretory clearance and pathway-mediated drug interactions during inflammation. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/690608v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@177e372org.highwire.dtl.DTLVardef@1f56bc4org.highwire.dtl.DTLVardef@17612e3org.highwire.dtl.DTLVardef@d2291f_HPS_FORMAT_FIGEXP M_FIG C_FIG Translational StatementSystemic inflammation increases cytokine concentrations and alters drug pharmacokinetics. Yet, cytokine regulation of renal drug transporters remains poorly defined, even though the kidney clears many anti-infective drugs via active secretion. Using an optimized primary human proximal tubular epithelial cell model that preserves expression and function of major renal transporters, we found that IL-1{beta} is the predominant cytokine that downregulates the mRNA and activity of OAT1-3, OCT2, and OAT4, while upregulating the mRNA and activity of OCTN1. We further showed that IL-1{beta}-driven downregulation of OAT1/3 occurs through JNK signaling, OAT2 through p38MAPK, and OCTN1 through NF-{kappa}B. These data provide quantitative inputs for physiologically based pharmacokinetic models to predict how inflammation alters renal transporter-mediated drug clearance, informing dose adjustment and risk assessment for disease-drug and drug-drug interactions in patients with inflammatory kidney disease or systemic infections. They also highlight signaling nodes where anti-inflammatory therapies might inadvertently modify renal drug transport.

pharmacology and toxicology↗