Biology subjects

Dhungana, H.

Publications and source records attributed to Dhungana, H..

3 recordsLinked to original sources

bioRxiv2024

Human iPSC-derived pericyte-like cells carrying APP Swedish mutation overproduce beta-amyloid and induce cerebral amyloid angiopathy-like changes

Alzheimers disease (AD) patients often exhibit cerebral amyloid angiopathy (CAA), i.e beta-amyloid (A{beta}) accumulation within cerebral blood vessels causing cerebrovascular dysfunction. Pericytes wrap around vascular capillaries, thus regulating cerebral blood flow, angiogenesis, and vessel stability. Vascular dysfunction can promote the development and progression of neurodegenerative diseases, yet the specific contribution of pericytes to AD pathology remains unclear. Here we show that human induced pluripotent stem cell (iPSC)-derived pericyte-like cells (iPLCs) can generate A{beta} peptides, and that the cells carrying Swedish mutation in amyloid precursor protein (APPswe) secrete 10 times more A{beta}1-42 than the control cells. Additionally, APPswe iPLCs have an impaired capacity to support angiogenesis and barrier integrity, exhibit a prolonged contractile response, and produce increased levels of pro-inflammatory cytokines upon inflammatory stimulation. These functional alterations in APPswe iPLCs are accompanied by transcriptional upregulation of actin cytoskeleton and extracellular matrix organization-related genes. Therefore, the APPswe mutation in iPLCs recapitulates several features of CAA pathology in vitro. Our iPSC-based vascular cell model may thus serve as a platform for drug discovery targeting vascular dysfunction in AD.

cell biology↗

bioRxiv2023

ciRS-7-miR7 regulate ischemia induced neuronal death via glutamatergic signaling

Brain functionality relies on finely tuned regulation of gene expression by networks of non-coding RNAs (ncRNAs) such as the one composed by the circular RNA ciRS-7 (also known as CDR1as), the microRNA miR-7 and the long non-coding RNA Cyrano. Here we describe ischemia induced alterations in the ncRNA network both in vitro and in vivo and in transgenic mice lacking ciRS-7 or miR-7. Our data show that cortical neurons downregulate ciRS-7 and Cyrano and upregulate miR-7 expression upon ischemic insults. Mice lacking ciRS-7 show reduced lesion size and motor impairment, whilst the absence of miR-7 alone leads to an increase in the ischemia induced neuronal death. Moreover, miR-7 levels in pyramidal excitatory neurons regulate dendrite morphology and glutamatergic signaling suggesting a potential molecular link to the in vivo phenotype. Our data reveal that ciRS-7 and miR-7 contribute to the outcome of ischemic stroke and shed new light into the pathophysiological roles of intracellular networks of non-coding RNAs in the brain.

molecular biology↗

bioRxiv2020

Patient iPSC-astrocytes show transcriptional and functional dysregulation in schizophrenia

Human astrocytes are multifunctional brain cells and may contribute to the pathophysiology of schizophrenia (SCZ). We differentiated astrocytes from induced pluripotent stem cells of monozygotic twins discordant for SCZ, and found sex-specific gene expression and signaling pathway alterations related particularly to inflammation and synaptic functions. While Ingenuity Pathway Analysis identified SCZ disease and synaptic transmission pathway changes in SCZ astrocytes, the most consistent findings were related to collagen and cell adhesion associated pathways. Neuronal responses to glutamate and GABA differed between astrocytes from control persons, affected twins, and their unaffected co-twins, and were normalized by clozapine treatment. SCZ astrocyte cell transplantation to the mouse forebrain caused gene expression changes in demyelination, synaptic dysfunction and inflammation pathways of mouse brain cells and resulted in behavioral changes in cognitive and olfactory functions. Altogether, our results show that astrocytes contribute to both familial risk and clinical manifestation of SCZ in a sex-specific manner.

neuroscience↗