Biology subjects

Hui, S. P.

Publications and source records attributed to Hui, S. P..

6 recordsLinked to original sources

bioRxiv2026

Hmox1/CO regulates retina regeneration via modulation of Wnt/β-catenin signalling and induction of vaspb in zebrafish

Muller glia (MG) in the zebrafish retina retain a latent stem cell capacity that is absent in mammals, yet the injury responsive signals that drive this reprogramming remain incompletely defined. Here, we identify heme oxygenase-1 (Hmox1), the stress-inducible, rate-limiting enzyme of heme catabolism, as a previously unrecognized regulator of this process. Following injury, hmox1a is selectively and rapidly induced among the heme oxygenase gene family, localizing to photoreceptors with expression peaking during the MG proliferation window. Pharmacological inhibition and morpholino mediated knockdown of Hmox1 dysregulate the acute inflammatory response, impair Muller glia-derived progenitor cell (MGPC) proliferation, and produce lasting deficits in retinal lamination, establishing Hmox1 as a potentially non-redundant, early-acting node required for structural recovery. Exogenous delivery of carbon monoxide (CO), a bioactive Hmox1 metabolite, partially rescues each of these phenotypes, functionally implicating CO as a key downstream effector. Mechanistically, Hmox1/CO signalling stabilizes {beta}-catenin likely via transcriptional repression of the Wnt antagonist dkk1b. This stabilized {beta}-catenin is enriched at a predicted Tcf7l2 site in the promoter of vaspb, which encodes an actin binding protein and is newly identified here as an injury-induced Wnt target gene. Bioinformatic and functional analyses further implicate Nfe2l2a (Nrf2) as a candidate intermediary bridging Hmox1/CO to Wnt regulation, with putative antioxidant response elements identified within the dkk1b locus. Together, these findings outline a putative Hmox1[->]CO[->]Nrf2[->]dkk1b[->]{beta}-catenin[->]vaspb relay coupling redox biology to Wnt-dependent glial reprogramming. Notably, HO-1 is similarly induced in stressed mammalian retina, yet Wnt/{beta}-catenin activation fails to sustain regeneration, positioning the Hmox1/CO axis as a candidate target for future investigation in mammalian retina regeneration.

neuroscience↗

bioRxiv2026

Comparative transcriptomic analysis reveals conserved injury responses and divergent molecular responses underlying early regenerative competence following traumatic brain injury

Abstract Background: Traumatic brain injury (TBI) is a leading cause of mortality and long term neurological disability worldwide. Adult mammals have limited regenerative capacity following central nervous system (CNS) injury, but zebrafish have a remarkable regenerative potential, providing an opportunity to identify molecular mechanisms associated with successful CNS repair. Methods: We have integrated publicly available acute phase TBI transcriptomic datasets from human, mouse, rat, and zebrafish studies published up to April 2026. Differential expression data were combined using restricted maximum likelihood (REML) based random effects meta analysis to account for biological and technical heterogeneity. Following ortholog mapping, we compared conserved injury responses with transcriptional programmes preferentially enhanced in zebrafish. Results: The acute molecular response to TBI is largely conserved across vertebrate species with predominant activation of cell cycle regulation, chromosome segregation, and interferon-mediated immune signalling genes. A conserved injury-responsive gene set further highlighted enrichment of mitotic and JAK-STAT signalling. In contrast, 54 zebrafish-enhanced genes displayed preferential activation of wound healing, extracellular matrix remodelling, integrin mediated signalling, and regulated immune responses. Protein protein interaction analysis identified STAT1, STAT3, FN1, CD44, ANXA2, and AXL as central hub genes connecting these injury and repair associated responses. Conclusions: Our study suggest that successful CNS regeneration is not driven by unique injury pathways but rather by coordinated modulation of conserved injury responses and additional molecular programmes that promote tissue remodelling and repair. These regeneration associated networks provide potential targets for future functional studies and may contribute to the development of regenerative therapeutic strategies for traumatic brain injury.

neuroscience↗

bioRxiv2026

A Novel MicroRNA-Odorant Receptor Axis Governs Neural Progenitor Cell Proliferation in Zebrafish CNS

Spinal cord injury causes irreversible neurological deficits in mammals; yet zebrafish achieve complete functional recovery through molecular mechanisms that remain poorly defined. In this study we emphasized on a critical miRNA-mediated regulation of Ependymo-radial glial (ERG) cell proliferation in zebrafish spinal cord. Using next-generation sequencing we constructed a spatiotemporal miRNA profile across multiple post-injury time points and identified dre-miR-N1 as a novel injury-responsive miRNA involved in ERG proliferation among several differentially expressed novel miRNAs. Fluorescent in situ hybridization confirmed its robust lesion-site expression and gain-of-function analysis demonstrated that dre-miR-N1 significantly impaired functional recovery. Target prediction and validation unexpectedly identified the odorant receptor gene or42a1 as a high-confidence target and a combinatorial approach of miRNA gain-of-function and or42a1 loss-of-function showed that dre-miR-N1 modulates the proliferative behaviour of or42a1-expressing ERG cells under both homeostatic and injury conditions. These findings uncover a previously unrecognized miRNA-odorant receptor axis governing injury-induced ERG cell expansion establishing a novel molecular framework for endogenous neural regeneration in zebrafish.

neuroscience↗

bioRxiv2024

Epigenetic cross-talk between Sirt1 and Dnmt1 promotes axonal regeneration after spinal cord injury in zebrafish

Though spinal cord injury (SCI) causes irreversible sensory and motor impairments in human, adult zebrafish retain the potent regenerative capacity by injury-induced proliferation of central nervous system (CNS)-resident progenitor cells to develop new functional neurons at the lesion site. The hallmark of SCI in zebrafish lies in a series of changes in the epigenetic landscape, specifically DNA methylation and histone modifications. Decoding the post-SCI epigenetic modifications is therefore critical for the development of therapeutic remedies that boost SCI recovery process. Here, we have studied on Sirtuin1 (Sirt1), a non-classical histone deacetylase that potentially play a critical role in neural progenitor cells (NPCs) proliferation and axonal regrowth following SCI in zebrafish. We investigated the role of Sirt1 in NPC proliferation and axonal regrowth in response to injury in the regenerating spinal cord and found that Sirt1 is involved in the induction of NPC proliferation along with glial bridging during spinal cord regeneration. We also demonstrate that Sirt1 plays a pivotal role in regulating the HIPPO pathway through deacetylation-mediated inactivation of Dnmt1 and subsequent hypomethylation of yap1 promoter, leading to the induction of ctgfa expression, which drives the NPC proliferation and axonal regrowth to complete the regenerative process. In conclusion, our study reveals a novel cross-talk between two important epigenetic effectors, Sirt1 and Dnmt1, in the context of spinal cord regeneration, establishing a previously undisclosed relation between Sirt1 and Yap1 which provides a deeper understanding of the underlying mechanisms governing injury-induced NPC proliferation and axonal regrowth. Therefore, we have identified Sirt1 as a novel, major epigenetic regulator of spinal cord regeneration by modulating the HIPPO pathway in zebrafish.

neuroscience↗

bioRxiv2023

Genetic Variations and Altered Blood mRNA Level of Circadian Genes and BDNF as Risk Factors of Post-Stroke Cognitive Impairment among Eastern Indians

BackgroundPost-stroke cognitive impairment (PSCI) is a clinical outcome in around 30% of post-stroke survivors. BDNF is a major gene in this regard. It regulates and being regulated by circadian rhythm. The circadian genes are correlated with stroke timings at molecular level. However, studies suggesting the role of these on susceptibility to PSCI is limited. AimWe aim here to determine a) genetic risk variants in circadian clock genes, BDNF and b) dysregulation in expression level of CLOCK, BMAL1 and BDNF, that may be associated with PSCI. MethodsBDNF (rs6265G/A, rs56164415C/T), CLOCK (rs1801260T/C, rs4580704G/C) and CRY2 (rs2292912C/G) genes variants were genotyped among 119 post-stroke survivors and 292 controls from Eastern part of India. In addition, we analysed their gene expression in PBMC from 15 PSCI cases and 12 controls. The mRNA data for BDNF was further validated by its plasma level through ELISA. ResultsAmong the studied variants, only rs4580704/CLOCK showed an overall association with PSCI (P = 0.001) and lower BMSE score. Its C allele showed a correlation with attention deficiency. The language and memory impairments showed association with rs6265/BDNF while the CC genotype of rs2292912/CRY2 negatively influenced language and executive function. A significant decrease in gene expression for CLOCK and BDNF in PBMC (influenced by specific genotypes) of PSCI patients was observed than controls. Unlike, Pro-BDNF, plasma level mBDNF was also lower in them. ConclusionsOur results suggest that the circadian genes and BDNF play a role in PSCI on both genetic and transcript level.

neuroscience↗

bioRxiv2021

Diversity and Function of Motile Ciliated Cell Types within Ependymal Lineages of the Zebrafish Brain

Motile cilia defects impair cerebrospinal fluid (CSF) flow, and can cause brain and spine disorders. To date, the development of ciliated cells, their impact on CSF flow and their function in brain and axial morphogenesis are not fully understood. Here, we have characterized motile ciliated cells within the zebrafish brain ventricles. We show that the ventricular surface undergoes significant restructuring through development, involving a transition from mono- to multiciliated cells (MCCs) driven by gmnc. MCCs are translationally polarized, co-exist with monociliated cells and generate directional flow patterns. Moreover, these ciliated cells have different developmental origins, and are genetically heterogenous with respect to expression of the Foxj1 family of ciliary master regulators. Finally, we show that cilia loss from specific brain regions or global perturbation of multiciliation does not affect overall brain or spine morphogenesis, but results in enlarged ventricles. Our findings establish that motile ciliated cells are generated by complementary and sequential transcriptional programs to support ventricular development.

neuroscience↗