Biology subjects

Cader, Z.

Publications and source records attributed to Cader, Z..

8 recordsLinked to original sources

bioRxiv2026

HTRA1 deficiency in COL4A1 mutant hiPSC-derived astrocytes, a convergent mechanism of cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a major contributor to stroke and cognitive decline, ultimately leading to vascular dementia (VaD). Genetic factors play a key role in disease susceptibility and progression, and variants in COL4A1 cause one of the most common forms of genetic cSVD. COL4A1 encodes the 1 chain of collagen type IV which is the major structural component of the basement membrane, a specialised extracellular matrix (ECM) structure, in the vasculature. In addition to this vascular basement membrane (vBM), in the central nervous system (CNS), the neurovascular unit (NVU) also has a unique parenchymal basement membrane (pBM) that is largely produced by astrocytes and forms a critical interface anchoring astrocyte end-feet to vascular cells. Together, these BMs play essential roles in regulating blood-brain barrier (BBB) function. However, the role of the pBM in cSVD has been relatively less investigated compared to the vBM. The lack of relevant human disease models that faithfully recapitulate the pBM, makes it difficult to dissect pBM-related cell-cell and cell-matrix interactions specific to cSVD, hindering the identification of effective therapeutic targets. In this study, we hypothesised that astrocyte-mediated ECM remodelling contributes to BBB dysfunction in COL4A1-associated cSVD. To investigate this, human induced pluripotent stem cells (iPSCs) derived from a patient carrying the COL4A1G755Rvariant and its isogenic control line were differentiated into astrocytes and brain microvascular endothelial cells (BMECs). Comparing to isogenic controls, the COL4A1G755Rastrocytes significantly reduced the expression of ECM-related genes and increased glutamate uptake. ECM preparations from COL4A1G755R astrocytes significantly damaged the tight junction (TJ) structure formed by control iPSC-BMECs and failed to rescue the TJ integrity in COL4A1G755R BMECs. The secretome from COL4A1G755Rastrocytes exacerbated the ECM defects in COL4A1G755R BMECs. Most importantly, COL4A1G755R astrocytes exhibited reduced expression of HTRA1, a serine protease that regulates both ECM turnover and homeostasis, and increased TGF-{beta} signalling. Functional rescue by recombinant human HTRA1 protein rescues TJ defects in COL4A1G755R BMECs, and normalized TGF-{beta} signalling and glutamate uptake in COL4A1G755R astrocytes. Together, these findings define a previously unrecognised astrocyte-driven pBM mechanism in COL4A1-associated cSVD and highlight HTRA1 in ECM remodelling as a therapeutic target for cSVD.

neuroscience↗

bioRxiv2025

A highly efficient method to differentiate CGRP-expressing peptidergic nociceptors from human induced pluripotent stem cells

Human cellular models of disease developed using induced pluripotent stem cells (iPSC) have enabled wide-ranging research from investigation of human disease mechanisms to phenotypic drug screens. Pain disorders such as neuropathic pain and headache remain areas of considerable unmet need and are considered high risk by pharma. Human iPSC-derived sensory neurons have already been used to accelerate translational research but the current differentiation protocols produce non-peptidergic nociceptors. We demonstrate for the first time the robust differentiation of hiPSC into peptidergic nociceptor lineage with high yield. These nociceptors express CGRP and TRPV1 whilst the non-peptidergic marker RET was completely absent. Functionally, the nociceptors show functional maturity including the expression of TTX-resistant currents and responding to TRPV1 and TRPA1 agonists. Importantly, they were able to release CGRP basally and upon stimulation by an inflammatory soup, which was inhibited upon the application of the 5-HT1B/1D/1F agonist, sumatriptan and topiramate, a migraine prophylactic drug. Overall, we report the successful generation of a novel in vitro functional peptidergic nociceptor model which will allow investigation of disease mechanisms in pain and for the development of new effective pain therapies.

neuroscience↗

bioRxiv2024

Human iPSCs from aged donors retain their mitochondrial aging signature

Aging represents the main risk factor for developing neurodegenerative disorders. One of the hallmarks of aging is mitochondrial dysfunction. Age-related mitochondrial alterations have been shown to affect mitochondrial energy metabolism and redox homeostasis as well as mitochondrial dynamics. In the present study, we addressed the question of whether or not, induced pluripotent stem cells (iPSCs) may be used as a model of "aging in a dish" to identify therapies at alleviating the aging of mitochondria. Notably, we could demonstrate that compared to human iPSCs from young donors, those from aged donors show impaired mitochondrial bioenergetics and exhibit a rise in reactive oxygen species generation. Furthermore, we demonstrate that iPSCs from aged donors present low mitochondrial mass and alterations of the morphology of the mitochondrial network. This study provides evidence that the aging phenotype is present at the mitochondrial level in iPSCs from aged donors, ranging from bioenergetics to dynamics. Thus, this model can be used for high through put screening to identify drugs that improve mitochondrial function. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=157 SRC="FIGDIR/small/589733v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@17c5ccorg.highwire.dtl.DTLVardef@bae9aaorg.highwire.dtl.DTLVardef@142d8e6org.highwire.dtl.DTLVardef@1adf519_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Preservation of an Aging-Associated Mitochondrial Signature in Advanced Human Neuronal Models

1.This study investigated whether induced pluripotent stem cell-derived neurons (iPSCsNs) and directly converted neurons (iNs) generated from the same cells of origin (human fibroblasts) represent aging-related characteristics on mitochondrial levels. There is still uncertainty regarding the potential for rejuvenation or preservation of an aging-associated donor signature in aged iPSCsNs upon transition through pluripotent states, while direct conversion retains the aging-associated mitochondrial impairments. Surprisingly, both aged neuronal models exhibited age-associated donor phenotypes, including decreased ATP, mitochondrial membrane potential, mitochondrial respiration, NAD+/NADH ratio, and increased radical levels and mitochondrial mass. Besides, a fragmented mitochondrial network was observed in both aged neuronal models. However, unlike aged iNs, aged iPSCsNs did not show a metabolic shift towards anaerobic glycolysis to compensate for the energy deficit. Moreover, the mRNA expression profile significantly differed between aged iPSCsNs and aged iNs. Our study indicates that aged iPSCsNs may experience rejuvenation in certain parameters, such as transcriptomics and the aging-associated glycolytic shift. Nevertheless, aged iPSCsNs can be a valuable tool for studying neuronal aging of mitochondrial parameters in vitro alongside aged iNs.

neuroscience↗

bioRxiv2023

iPSC-Astrocyte morphology reflects patient clinical markers

Human iPSCs provide powerful cellular models of Alzheimers disease (AD) and offer many advantages over non-human models, including the potential to reflect variation in individual-specific pathophysiology and clinical symptoms Previous studies have demonstrated that iPSC-neurons from individuals with Alzheimers disease (AD) reflect clinical markers, including {beta}-amyloid (A{beta}) levels and synaptic vulnerability. However, despite neuronal loss being a key hallmark of AD pathology, many risk genes are predominantly expressed in glia, highlighting them as potential therapeutic targets. In this work iPSC-derived astrocytes were generated from a cohort of individuals with high versus low levels of the inflammatory marker YKL-40, in their cerebrospinal fluid (CSF). iPSC-derived astrocytes were treated with exogenous A{beta} oligomers and high content imaging demonstrated a correlation between astrocytes that underwent the greatest morphology change from patients with low levels of CSF-YKL-40 and more protective APOE genotypes. This finding was subsequently verified using similarity learning as an unbiased approach. This study shows that iPSC-derived astrocytes from AD patients reflect key aspects of the pathophysiological phenotype of those same patients, thereby offering a novel means of modelling AD, stratifying AD patients and conducting therapeutic screens. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/548687v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1df3486org.highwire.dtl.DTLVardef@f184d8org.highwire.dtl.DTLVardef@48a33dorg.highwire.dtl.DTLVardef@d53a90_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

A novel human iPSC model of COL4A1/A2 small vessel disease unveils a key pathogenic role of matrix metalloproteinases in extracellular matrix abnormalities

Abstract/SummaryCerebral small vessel disease (SVD) affects the small vessels in the brain and is a leading cause of stroke and dementia. Emerging evidence supports a role of the extracellular matrix (ECM), at the interface between blood and brain, in the progression of SVD pathology but this remains poorly characterized. To address ECM role in SVD, we developed a co-culture model of mural and endothelial cells using human induced pluripotent stem cells from patients with COL4A1/A2 SVD-related mutations. This model revealed that these mutations induce apoptosis, migration defects, ECM remodelling and transcriptome changes in mural cells. Importantly, these mural cell defects exert a detrimental effect on endothelial cells tight junctions through paracrine actions. COL4A1/A2 models also express high levels of matrix metalloproteinases (MMP) and inhibiting MMP activity partially rescues the ECM abnormalities and mural cell phenotypic changes. These data provide a basis for targeting MMP as a therapeutic opportunity in SVD. HighlightsO_LIA novel human iPSC-derived model of genetic SVD due to collagen IV (COL4A1/A2) mutations is described C_LIO_LIMural cells expressing COL4A1/A2 mutations have prominent ECM abnormalities as seen in patients and mouse models and contribute to endothelial cells defects C_LIO_LIECM and endothelial cells abnormalities can be rescued by MMP inhibition in the COL4A1/A2 model C_LI

cell biology↗

bioRxiv2020

TASK-3 Two-Pore Potassium Channels drive neuronal excitability of the circadian clock and entrainment to challenging light environments

The suprachiasmatic nucleus (SCN), the mammalian circadian clock, is a heterogenous structure made of several neuron types that generate a circadian electrical activity profile. However, it is unclear how such regulation in endogenous neuronal excitability is maintained. Background two-pore domain potassium channels (K2P), such as TASK-3, play an important role in inhibiting neuronal activity. Here, we utilize a TASK-3 KO mouse model to unravel the role played by this channel in SCN circadian neuronal regulation and behavioral photoentrainment. Our results reveal that TASK-3 is needed to adapt to challenging lighting conditions, such as those experienced through seasonal changes and jet lag. From our investigations this appears to be very distinct from pathways that drive acute, one-off adjustments in clock phase, in response to single pulses of light. These findings provide crucial information on the intricate pathways linking clock output to behavioral adaptation to light-dark cycles.

neuroscience↗

bioRxiv2018

Headache and type 2 diabetes association: a US national ambulatory case-control study.

ObjectiveWe investigate the joint observation between type 2 diabetes and headache using a case-control study of a US ambulatory dataset.\n\nBackgroundRecent whole-population cohort studies propose that type 2 diabetes may have a protective effect against headache prevalence. With headaches ranked as a leading cause of disability, headache-associated comorbidities could help identify shared molecular mechanisms.\n\nMethodsWe performed a case-control study using the US National Ambulatory Medical Care Survey, 2009, on the joint observation between headache and specific comorbidities, namely type 2 diabetes, hypertension and anxiety, for all patients between 18 and 65 years of age. The odds ratio of having a headache and a comorbidity were calculated using conditional logistic regression, controlling for gender and age over a study population of 3,327,947 electronic health records in the absence of prescription medication data.\n\nResultsWe observed estimated odds ratio of 0.89 (95% CI: 0.83-0.95) of having a headache and a record of type 2 diabetes over the population, and 0.83 (95% CI: 2.02-2.57) and 0.89 (95% CI: 3.00-3.49) for male and female, respectively.\n\nConclusionsWe find that patients with type 2 diabetes are less likely to present a recorded headache indication. Patients with hypertension are almost twice as likely of having a headache indication and patients with an anxiety disorder are almost three times as likely. Given the possibility of confounding indications and prescribed medications, additional studies are recommended.

epidemiology↗