Biology subjects

Rehen, S. K.

Publications and source records attributed to Rehen, S. K..

15 recordsLinked to original sources

bioRxiv2026

Impaired ZNF560 repression during induced pluripotent stem cell reprogramming indicates early epigenetic alterations in Schizophrenia

Despite extensive epigenetic reprogramming, induced pluripotent stem cells (iPSC) from schizophrenia patients (SZ) retain several molecular and functional features of this disease. Transcriptomic and epigenomic analyses were performed in iPSC of SZ and healthy control subjects (HC). Transcriptional profiles were largely similar between SZ and HC iPSC, whereas pronounced differences emerged following neural differentiation, with SZ NSC exhibiting dysregulation of genes involved in neurodevelopment and synaptic function. ZNF5c0 was identified as a uniquely and consistently upregulated gene in SZ iPSC, robustly discriminating SZ from HC iPSC. Epigenomic profiling revealed increased chromatin accessibility and reduced DNA methylation at the ZNF5c0 promoter in SZ iPSC. ChIP-seq data suggested that ZNF560 can bind to promoters of genes implicated in synaptic signaling and neuronal development. Moreover, a subset of these genes was found to be differentially expressed in SZ neural stem cells. Together, our results identify ZNF5c0 as a reprogramming-resistant epigenetic marker of schizophrenia and suggest an altered KRAB-ZNF-mediated regulation in early neurodevelopmental pathways underlying this disorder.

cell biology↗

bioRxiv2025

Microcephaly-like phenotype triggered by novel reassortant and prototypic Oropouche Virus strains in brain organoids

Oropouche virus (OROV) is an emerging arbovirus currently spreading across South America, with increasing reports of neurological manifestations, severe systemic disease, and congenital abnormalities. Although traditionally associated with mild febrile illness, the recent geographic expansion and surge in OROV outbreaks have prompted attention to its neurotropic potential. Here, we investigated the impact of OROV infection on human neural development using neural stem cells (NSCs) and brain organoids derived from induced pluripotent stem cells. Recent OROV isolates exhibiting genomic reassortment and associated with increased neurological manifestations were compared with a prototypical strain for the ability to infect NSCs, early-stage organoids, and more mature cortical-like tissues. OROV infected NSCs efficiently, leading to widespread cell death, depletion of proliferative progenitors, and disruption of neuroepithelial organization. Transcriptomic profiling of infected NSCs revealed a robust reduction of antiviral response genes and an enrichment of pathways related to viral replication, apoptosis, and the inhibition of stem cell maintenance and neuronal differentiation. These molecular signatures aligned with the phenotypic collapse of progenitor pools and cortical structure observed in organoids. OROV antigens were detected in both astrocytes and neurons, with associated structural degeneration. Although a substantial overlap in differentially expressed genes was observed between the two viral strains, some strain-specific transcriptional responses were detected. However, these modest differences did not translate into distinct cytopathogenic effects between the two viral strains. These phenotypes, including the reduced growth of infected organoids, resemble those previously described with Zika virus in the same cellular models, supporting the hypothesis that OROV may impair brain development. Together, these results reveal a previously unrecognized neuroteratogenic potential of OROV strains and provide mechanistic insight into the potential of OROV to induce microcephaly-like phenotypes, highlighting its relevance as a significant threat to maternal-fetal health.

neuroscience↗

bioRxiv2025

Lysergic Acid Diethylamide extends lifespan in Caenorhabditis elegans

Aging is modulated by nutrient-sensing pathways that integrate metabolic and hormonal cues to regulate growth, stress resilience, and lifespan. Caloric restriction (CR), a well-established intervention, extends longevity in diverse species through modulation of conserved nutrient-sensing pathways, including TOR signaling. Lysergic acid diethylamide (LSD), a classic serotonergic psychedelic with emerging therapeutic applications, remains largely unexplored in the context of aging. Here, we show that LSD treatment significantly extends lifespan in Caenorhabditis elegans and reduces age-associated lipofuscin accumulation, suggesting delayed age-associated decline. LSD induces several phenotypes that overlap with those observed in some caloric restriction paradigms, including reduced reproductive output, decreased body size, and the absence of an additive effect in lifespan assay performed in dietary restriction model, without apparent decreasing in food intake. In addition, LSD treatment modulates lipid stores and other cellular readouts associated with nutrient-sensing physiology. Together, these findings suggest that LSD engages evolutionarily conserved pathways linked to longevity and identify this compound as a tool to investigate serotonergic control of aging biology.

neuroscience↗

bioRxiv2024

hiPSC-derived astrocytes from individuals with schizophrenia promote alterations in phagocytosis and chemotaxis of microglial-like cells

Neuroinflammation, particularly astrocyte reactivity, is increasingly linked to schizophrenia (SCZ). Yet, the crosstalk between astrocytes and microglia in SCZ, especially under pro-inflammatory conditions, remains unclear. Here, we employed human induced-pluripotent stem cells to compare how astrocytes from five age-matched individuals with SCZ and five neurotypical controls, upon stimulation with TNF-, affected microglial biology. TNF-[a] stimulation of SCZ astrocytes, relative to their control counterparts, triggered increased mRNA expression of pro-inflammatory cytokines and CX3CL1. Interestingly, transcriptomic and gene set enrichment analyses revealed that reactive SCZ astrocytes promoted the downregulation of biological processes associated with immune cell proliferation and activation, phagocytosis and cell migration in induced microglial-like cells (iMGs). Under such conditions, iMGs assumed a dystrophic/senescent-like phenotype, which was associated with accelerated transcriptional aging. Functional validations showed that TNF-[a]-stimulated SCZ astrocytes promoted reduced synaptoneurosomes phagocytosis by iMGs. Interestingly, only reactive control astrocytes were capable to induce significant microglial migration in a CX3CR1-dependent manner, despite the greater CX3CL1 secretion by reactive SCZ astrocytes compared to their stimulated control counterparts. This was likely due to SCZ astrocytes triggered reduction in CX3CR1 plasma membrane levels in iMGs. Altogether, these findings suggest that astrocytes contribute to SCZ pathology by altering normal microglial function and inducing a dystrophic phenotype. Main pointsO_LISCZ astrocytes display an increased pro-inflammatory profile upon stimulation with TNF-. C_LIO_LIReactive SCZ astrocytes induce microglial-like cells to assume a dystrophic phenotype. C_LIO_LIReactive SCZ astrocytes secreted factors impair microglial-like cells synaptoneurosome phagocytosis and limit their migration. C_LI

neuroscience↗

bioRxiv2024

LSD Modulates Proteins Involved in Cell Proteostasis, Energy Metabolism and Neuroplasticity in Human Brain Organoids

Proteomic analysis of human cerebral organoids may reveal how psychedelics regulate biological processes, shedding light on drug-induced changes in the brain. This study elucidates the proteomic alterations induced by lysergic acid diethylamide (LSD) in human cerebral organoids. By employing high-resolution mass spectrometry-based proteomics, we quantitatively analyzed the differential abundance of proteins in cerebral organoids exposed to LSD. Our findings indicate changes in proteostasis, energy metabolism, and neuroplasticity-related pathways. Specifically, LSD exposure led to alterations in protein synthesis, folding, autophagy, and proteasomal degradation, suggesting a complex interplay in the regulation of neural cell function. Additionally, we observed modulation in glycolysis and oxidative phosphorylation, crucial for cellular energy management and synaptic function. In support of the proteomic data, complementary experiments demonstrated LSDs potential to enhance neurite outgrowth in vitro, confirming its impact on neuroplasticity. Collectively, our results provide a comprehensive insight into the molecular mechanisms through which LSD may affect neuroplasticity and potentially contribute to therapeutic effects for neuropsychiatric disorders.

neuroscience↗

bioRxiv2023

Systematic Characterization of LSD metabolites in C. elegans by ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry

Psychedelic compounds have gained renewed interest for their potential therapeutic applications, but their metabolism and effects on complex biological systems remain poorly understood. Here, we present a systematic characterization of LSD metabolites in the model organism Caenorhabditis elegans using state-of-the-art analytical techniques. By employing ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMS/MS), we identified and quantified a range of LSD metabolites, shedding light on their metabolic pathways and offering insights into their pharmacokinetics. Our study demonstrates the suitability of C. elegans as a valuable model system for investigating the metabolism of psychedelic compounds and provides a foundation for further research on the therapeutic potential of LSD. These findings contribute to the growing body of knowledge in the field and highlight the importance of advanced analytical methodologies in elucidating the effects of psychedelic substances on biological systems.

pharmacology and toxicology↗

bioRxiv2023

Saxitoxin potentiates Zika virus-induced cell death in human neurons but not in neural progenitors and astrocytes

The Zika virus (ZIKV) outbreak in Brazil between 2015 and 2016 was associated with an increased prevalence of severe congenital malformations, including microcephaly. Notably, the distribution of microcephaly cases was not uniform across the country, with a disproportionately higher incidence recorded in the Northeast region (NE). Our previous work demonstrated that saxitoxin (STX), a toxin ubiquitously present in the drinking water reservoirs of the NE, exacerbated the damaging effects of ZIKV on the developing brain. In the present study, we hypothesized that STXs impact might vary among different neural cell types. Our experimental observations suggest that exposure to STX potentiates the neurotoxic effect of Zika Virus (ZIKV) on human neuronal cells. However, while ZIKV infection demonstrated severe impacts on astrocytes and neural stem cells (NSCs), the addition of STX did not exacerbate these effects. We observed that neurons subjected to STX exposure were more prone to apoptosis and displayed a higher number of ZIKV-infected cells. These findings suggest that STX exacerbates the harmful effects of ZIKV on neurons, thereby providing a plausible explanation for the heightened severity of ZIKV-induced congenital malformations observed in Brazils NE. This study underscores the importance of understanding the interactive effects of environmental toxins and infectious pathogens on neural development, with potential implications for public health policies and interventions.

neuroscience↗

bioRxiv2022

Schizophrenia-derived hiPSC brain microvascular endothelial cells show impairments in angiogenesis and blood-brain barrier function

Schizophrenia (SZ) is a complex neuropsychiatric disorder, affecting 1% of the world population. Long-standing clinical observations and molecular data have pointed out a possible vascular deficiency that could be acting synergistically with neuronal dysfunction in SZ. As SZ is a neurodevelopmental disease, the use of human induced pluripotent stem cells (hiPSC) allows disease biology modeling retaining the patients unique genetic signature. Previously, we reported a VEGF-A signaling impairment in SZ-hiPSC derived neural lineages leading to a decreased angiogenesis. Here, we present a functional characterization of SZ-derived brain microvascular endothelial-like cells (BEC), the counterpart of the neurovascular crosstalk, revealing an intrinsically defective Blood-Brain Barrier (BBB) phenotype. Transcriptomic assessment of genes related to endothelial function among three control (Ctrl BEC) and five schizophrenia patients derived BEC (SZP BEC), revealed that SZP BEC have a distinctive expression pattern of angiogenic and BBB-associated genes. Functionally, SZP BEC showed a decreased angiogenic response in vitro and higher transpermeability than Ctrl BEC. Immunofluorescence staining revealed less expression and altered distribution of tight junction proteins in SZP BEC. Moreover, SZP BECs secretome reduced barrier capacities in the brain microvascular endothelial cell line HCMEC/D3 and in an in vivo permeability assay in mice. Overall, our results describe an intrinsic failure of SZP BEC for proper barrier function. These findings are consistent with the hypothesis that traces schizophrenia origins to brain development and BBB dysfunction.

cell biology↗

bioRxiv2022

Induced pluripotent stem cell-derived astrocytes from patients with schizophrenia exhibit an inflammatory phenotype that affects vascularization

Molecular and functional abnormalities of astrocytes have been implicated in the etiology and pathogenesis of schizophrenia (SCZ). In this study, we examined the proteome, inflammatory responses, and secretome effects on vascularization of human induced pluripotent stem cell (hiPSC)-derived astrocytes from patients with SCZ. Proteomic analysis revealed alterations in proteins related to immune function and vascularization. Reduced expression of the nuclear factor kappa B (NF-{kappa}B) p65 subunit was observed in these astrocytes, with no incremental secretion of cytokines after tumor necrosis factor alpha (TNF-) stimulation. Among inflammatory cytokines, secretion of interleukin (IL)-8 was found particularly elevated in SCZ-patient-derived- astrocyte conditioned medium (ASCZCM). In a chicken chorioallantoic membrane (CAM) assay, ASCZCM reduced the diameter of newly grown vessels, and this effect could be mimicked with exogenous addition of IL-8. Taken together, our results suggest that SCZ astrocytes are immunologically dysfunctional and may consequently affect vascularization through secreted factors.

neuroscience↗

bioRxiv2021

Age-linked suppression of lipoxin A4 mediates cognitive deficits in mice and humans

Age increases the risk for cognitive impairment and is the single major risk factor for Alzheimers disease (AD), the most prevalent form of dementia in the elderly. The pathophysiological processes triggered by aging that render the brain vulnerable to dementia involve, at least in part, changes in inflammatory mediators. Here we show that lipoxin A4 (LXA4), a lipid mediator of inflammation resolution known to stimulate endocannabinoid signaling in the brain, is reduced in the aging central nervous system. We demonstrate that genetic suppression of 5-lipoxygenase (5-LOX), the enzyme mediating LXA4 synthesis, promotes learning impairment in mice. Conversely, administration of exogenous LXA4 attenuated cytokine production and memory loss induced by inflammation in mice. We further show that cerebrospinal fluid LXA4 is reduced in patients with dementia and positively associates with memory performance, brain-derived neurotrophic factor (BDNF), and AD-linked amyloid-. Our findings suggest that reduced LXA4 levels may lead to vulnerability to age-related cognitive disorders and that promoting LXA4 signaling may comprise an effective strategy to prevent early cognitive decline in AD.

neuroscience↗

bioRxiv2021

Quantitative profiling of axonal guidance proteins during the differentiation of human neurospheres

Axon guidance is required for the establishment of brain circuits. Whether much of the molecular basis of axon guidance is known from animal models, the molecular machinery coordinating axon growth and pathfinding in humans remains to be elucidated. The use of induced pluripotent stem cells (iPSC) from human donors has revolutionized in vitro studies of the human brain. iPSC can be differentiated into neuronal stem cells which can be used to generate neural tissue-like cultures, known as neurospheres, that reproduce, in many aspects, the cell types and molecules present in the brain. Here, we analyzed quantitative changes in the proteome of neurospheres during differentiation. Relative quantification was performed at early time points during differentiation using iTRAQ-based labeling and LC-MS/MS analysis. We identified 6,438 proteins, from which 433 were downregulated and 479 were upregulated during differentiation. We show that human neurospheres have a molecular profile that correlates to the fetal brain. During differentiation, upregulated pathways are related to neuronal development and differentiation, cell adhesion, and axonal guidance whereas cell proliferation pathways were downregulated. We developed a functional assay to check for neurite outgrowth in neurospheres and confirmed that neurite outgrowth potential is increased after 10 days of differentiation and is enhanced by increasing cyclic AMP levels. The proteins identified here represent a resource to monitor neurosphere differentiation and coupled to the neurite outgrowth assay can be used to functionally explore neurological disorders using human neurospheres as a model.

neuroscience↗

bioRxiv2019

The cyanobacterial saxitoxin exacerbates neural cell death and brain malformations induced by Zika virus

The northeast (NE) region of Brazil commonly goes through drought periods, which favor cyanobacterial blooms, capable of producing neurotoxins with implications for human and animal health. The most severe dry spell in the history of Brazil occurred between 2012 and 2016. Coincidently, the highest incidence of microcephaly associated with the Zika virus (ZIKV) outbreak was described in the NE region of Brazil during the same years. In this work, we tested the hypothesis that saxitoxin (STX), a neurotoxin produced in South America by the freshwater cyanobacteria Raphidiopsis raciborskii, could have contributed to the most severe Congenital Zika Syndrome (CZS) profile described worldwide. Quality surveillance showed higher cyanobacteria amounts and STX occurrence in human drinking water supplies of NE compared to other regions of Brazil. Experimentally, we described that STX doubled the amount of ZIKV-induced neural cell death in progenitor areas of human brain organoids, while the chronic ingestion of water contaminated with STX before and during gestation caused brain abnormalities in offspring of ZIKV-infected immunocompetent C57BL/6J mice. Our data indicate that saxitoxin-producing cyanobacteria is overspread in water reservoirs of the NE and might have acted as a co-insult to ZIKV infection in Brazil. These results raise a public health concern regarding the consequences of arbovirus outbreaks happening in areas with droughts and/or frequent freshwater cyanobacterial blooms.\n\nAuthor summaryThe uncontrolled spreading of cyanobacteria in drinking water reservoirs has been the cause of serious public health problems worldwide. Toxin-producing cyanobacterial blooms commonly occur during drought periods in the northeast (NE) region of Brazil. During Zika Virus (ZIKV) outbreak in 2015-16, Brazilian NE showed disproportionately higher microcephaly incidence. Here, we test the hypothesis that the cyanotoxin saxitoxin (STX) may act as a co-insult for ZIKV. Water quality surveillance data showed increased cyanobacteria population and higher STX amount in NE region during 2014-2018. In vitro, we observed that neural progenitor cell death was doubled after STX exposure to ZIKV-infected brain organoids. In vivo, chronic ingestion of STX during gestational period potentiated ZIKV-derived brain abnormalities in newborn mice. Our study provides new insights that may explain the discrepancies among Brazilian regions regarding CZS severity. Moreover, the data highlight the importance of cyanobacteria and cyanotoxin freshwater monitoring for future arbovirus outbreaks.

neuroscience↗

bioRxiv2019

Short and long TNF-alpha exposure recapitulates canonical astrogliosis events in human induced pluripotent stem cells-derived astrocytes

Astrogliosis comprises a variety of changes in astrocytes that occur in a context-specific manner, triggered by temporally diverse signaling events that vary with the nature and severity of brain insults. However, most mechanisms underlying astrogliosis were described using animal models, which fail to reproduce some aspects of human astroglial signaling. Here, we report an in vitro model to study astrogliosis using human induced pluripotent stem cells (iPSC)-derived astrocytes which replicates aspects temporally intertwined of reactive astrocytes in vivo. We analyzed the time course of astrogliosis by measuring nuclear translocation of NF-kB, secretion of cytokines and changes in morphological phenotypes of human iPSC-derived astrocytes exposed to TNF-. It was observed the NF-kB nuclear translocation, increases either in the inflammation-related cytokines secretion and gene expression for IL-1{beta}, IL-6 and TNF- following 24 h TNF- stimulation. After 5 days, human iPSC-derived astrocytes exposed to TNF- exhibited increases in vimentin and GFAP immunolabeling, elongated shape and shrinkage of nuclei, which is typical phenotypes of astrogliosis. Moreover, about a 50% decrease in D-[3H] aspartate uptake was observed over the astrogliosis course with no evident cell damage, which suggests astrocytic dysfunction. Taken together, our results indicate that cultured human iPSC-derived astrocytes reproduce canonical events associated to astrogliosis in a time dependent fashion. Our findings may contribute to a better understanding of mechanisms governing human astrogliosis. Furthermore, the approach described here presents a potential applicability as a platform to uncover novel biomarkers and new drug targets to refrain astrogliosis associated to human brain disorders.

neuroscience↗

bioRxiv2018

Generation Of iPSC-Derived Human Peripheral Sensory Neurons Releasing Substance P Elicited By TRPV1 Agonists

Neural crest stem cells (NCPCs) have been shown to differentiate into various cell types and tissues during embryonic development, including sensory neurons. The few studies addressing the generation of NCPCs and peripheral sensory neurons (PSNs) from human induced Pluripotent Stem Cells (hiPSCs), generated sensory cells without displaying robust activity. Here, we describe an efficient strategy for hiPSCs differentiation into NCPCs and functional PSNs using chemically defined media and factors to achieve efficient differentiation, confirmed by the expression of specific markers. After 10 days hiPSCs differentiated into NCPCs, cells were then maintained in neural induction medium containing defined growth factors for PSNs differentiation, followed by 10 days in neonatal human epidermal keratinocytes-(HEKn-) conditioned medium. We observed a further increase in PSN markers expression and neurites length after conditioned medium treatment. The resulting neurons released substance P (SP) in response to nociceptive agents such as anandamide and resiniferatoxin. Anandamide induced substance P release via activation of TRPV1 and not CB1. Transcriptomic analysis of the PSNs revealed the main dorsal root ganglia (DRG) neuronal markers and a transcriptional profile compatible with C-LTMR. TRPV1 was detected by immunofluorescence and RNA-Seq in multiple experiments. In conclusion, the developed strategy generated PSNs useful for drug screening that could be applied to patient-derived hiPSCs, consisting in a powerful tool to model human diseases in vitro.

neuroscience↗

bioRxiv2017

Short term changes in the proteome of human cerebral organoids induced by 5-methoxy-N,N-dimethyltryptamine

Dimethyltryptamines are hallucinogenic serotonin-like molecules present in traditional Amerindian medicine (e.g. Ayahuasca, Virola) recently associated with cognitive gains, antidepressant effects and changes in brain areas related to attention, self-referential thought, and internal mentation. Historical and technical restrictions impaired understanding how such substances impact human brain metabolism. Here we used shotgun mass spectrometry to explore proteomic differences induced by dimethyltryptamine (5-methoxy-N, N-dimethyltryptamine, 5-MeO-DMT) on human cerebral organoids. Out of the 6,728 identified proteins, 934 were found differentially expressed in 5-MeO-DMT-treated cerebral organoids. In silico systems biology analyses support 5-MeO-DMTs anti-inflammatory effects and reveal a modulation of proteins associated with the formation of dendritic spines, including proteins involved in cellular protrusion formation, microtubule dynamics and cytoskeletal reorganization. Proteins involved in long-term potentiation were modulated in a complex manner, with significant increases in the levels of NMDAR, CaMKII and CREB, but a reduction of PKA and PKC levels. These results offer possible mechanistic insights into the neuropsychological changes caused by the ingestion of substances rich in dimethyltryptamines.

neuroscience↗