Biology subjects

Yeung, C. K.

Publications and source records attributed to Yeung, C. K..

4 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↗

bioRxiv2025

Evaluation of toxicological mechanisms of ochratoxin-A in human primary proximal tubule epithelial cells

Ochratoxin-A (OTA) is a ubiquitous mycotoxin contaminant in food products and a known nephrotoxin. OTA is hypothesized to be a potential environmental agent causing chronic kidney disease of unknown etiology (CKDu), however the mechanism of OTA toxicity in the human kidney remains elusive. This study aims to elucidate OTA-induced molecular toxicological pathways using primary human proximal tubule epithelial cells (PTECs). We demonstrated that exposure to OTA (10 M) induces over 7000 differentially expressed genes, including key regulators of mitochondrial fission and fusion. This was confirmed at the cellular level by confocal microscopy, where a breakdown of the mitochondrial network was observed at 100 nM OTA. Crucially, OTA was found to significantly induce reactive oxygen species (mROS) and inhibit basal mitochondrial oxidative phosphorylation as well as glycolysis through measurements of oxygen consumption rate and extracellular acidification, indicating reduced cellular energetics and mitochondrial toxicity. The previously reported downregulation of NRF2 target antioxidant response elements was not able to be recovered with co-administration of NRF2 agonists, sulforaphane or tert-butylhydroquinone, suggesting a possible mechanism of inhibition of NRF2 nuclear translocation or DNA binding. In conclusion, we demonstrate that OTA induces oxidative stress, mitochondrial dysfunction, and reduced ATP production, leading to a senescent-like state in PTECs characteristic of renal disease progression. These findings provide insight into early toxicological endpoints induced by OTA which have been established as pathophysiological changes involved in chronic kidney disease. HighlightsO_LIOTA exposure suppresses oxidative phosphorylation and glycolysis C_LIO_LIOTA exposure disrupts mitochondrial fission and fusion C_LIO_LIOTA induced mitochondrial ROS C_LIO_LIEarly mitochondrial stress may underlie OTA-associated CKDu risk C_LI

pharmacology and toxicology↗

bioRxiv2021

Multi-omic Characterization of Human Tubular Epithelial Cell Response to Serum

Proteinuria, the spillage of serum proteins into the urine, is a feature of glomerulonephritides, podocyte disorders and diabetic nephropathy. However, the response of tubular epithelial cells to serum protein exposure has not been systematically characterized. Using transcriptomic profiling we studied serum-induced changes in primary human tubular epithelial cells cultured in 3D microphysiological devices. Serum proteins induced cellular proliferation, cytokine secretion and activated a coordinated stress response. We orthogonally confirmed our findings by comparing the transcriptomic and epigenomic landscapes of intact human kidney cortex and isolated tubular epithelial cells cultured in fetal bovine serum. Importantly, key transcriptomic programs in response to either type of serum exposure remained consistent, including comparisons to an established mouse model of kidney injury. This serum-induced transcriptional response was dominated by switching off of nuclear receptor-driven programs and activation of AP-1 and NF-{kappa}B signatures in the tubular epigenomic landscape. These features of active regulation were seen at canonical kidney injury genes (HAVCR1) and genes associated with COVID-19 (ACE2, IL6). Our data provide a reference map for dissecting the regulatory and transcriptional response of kidney tubular epithelial cells injury induced by serum.

cell biology↗

bioRxiv2020

Bridging the gap between in silico and in vivo: modeling opioid disposition in a kidney proximal tubule microphysiological system

BackgroundOpioid overdose, dependence, and addiction are a major public health crisis. Patients with chronic kidney disease (CKD) are at high risk of opioid overdose, therefore novel methods that provide accurate prediction of kidney clearance (CLr) and systemic disposition of opioids in CKD patients can facilitate the optimization of therapeutic regimens. MethodsWe conducted prediction of kidney clearance and systemic disposition of morphine and its active metabolite morphine-6-glucuronide (M6G) in CKD patients using a vascularized human proximal tubule microphysiological system (VPT-MPS) coupled with a parent-metabolite full body physiologically-based pharmacokinetic (PBPK) model. ResultsThe VPT-MPS, populated with a human umbilical vein endothelial cell (HUVEC) channel and an adjacent human primary proximal tubular epithelial cells (PTEC) channel, successfully demonstrated secretory transport of morphine and M6G from the HUVEC channel into the PTEC channel in a time-dependent manner; transporter inhibitors decreased translocation by 74.3% and 63.6%, respectively. The in vitro data generated by VPT-MPS were incorporated into a mechanistic kidney model and parent-metabolite full body PBPK model to predict CLr and systemic disposition of morphine and M6G. The model successfully predicted CLr within 1.5-fold, and the plasma concentration-time profiles of morphine and M6G in both healthy subjects and CKD patients, with absolute average fold error values <1.5. ConclusionsA microphysiological system together with mathematical modeling successfully predicted kidney clearance and systemic disposition of opioids in CKD patients and healthy subjects.

pharmacology and toxicology↗