Biology subjects

Toro, C.

Publications and source records attributed to Toro, C..

5 recordsLinked to original sources

bioRxiv2024

Cellular Modeling of CLN6 with IPSC-derived Neurons and Glia

Neuronal ceroid lipofuscinosis (NCL), type 6 (CLN6) is a neurodegenerative disorder associated with progressive neurodegeneration leading to dementia, seizures, and retinopathy. CLN6 encodes a resident-ER protein involved in trafficking lysosomal proteins to the Golgi. CLN6p deficiency results in lysosomal dysfunction and deposition of storage material comprised of Nile Red+ lipids/proteolipids that include subunit C of the mitochondrial ATP synthase (SUBC). White matter involvement has been recently noted in several CLN6 animal models and several CLN6 subjects had neuroimaging was consistent with leukodystrophy. CLN6 patient-derived induced pluripotent stem cells (IPSCs) were generated from several of these subjects. IPSCs were differentiated into oligodendroglia or neurons using well-established small-molecule protocols. A doxycycline-inducible transgenic system expressing neurogenin-2 (the I3N-system) was also used to generate clonal IPSC-lines (I3N-IPSCs) that could be rapidly differentiated into neurons (I3N-neurons). All CLN6 IPSC-derived neural cell lines developed significant storage material, CLN6-I3N-neuron lines revealed significant Nile Red+ and SUBC+ storage within three and seven days of neuronal induction, respectively. CLN6-I3N-neurons had decreased tripeptidyl peptidase-1 activity, increased Golgi area, along with increased LAMP1+ in cell bodies and neurites. SUBC+ signal co-localized with LAMP1+ signal. Bulk-transcriptomic evaluation of control- and CLN6-I3N-neurons identified >1300 differentially-expressed genes (DEGs) with Gene Ontogeny (GO) Enrichment and Canonical Pathway Analyses having significant changes in lysosomal, axonal, synaptic, and neuronal-apoptotic gene pathways. These findings indicate that CLN6-IPSCs and CLN6-I3N-IPSCs are appropriate cellular models for this disorder. These I3N-neuron models may be particularly valuable for developing therapeutic interventions with high-throughput drug screening assays and/or gene therapy.

neuroscience↗

bioRxiv2023

Xanthomonas euvesicatoria effector XeAvrRxo1 triggers a Rxo1-mediated defense response in Nicotiana benthamiana and its chaperone Xe4429 functions as an antitoxin, an expression repressor, and an enhancer of XeAvrRxo1 secretion

Xanthomonas euvesicatoria (X. euvesicatoria) is the causal agent of bacterial spot disease that threatens pepper and tomato production around the globe. X. euvesicatoria gene Xe4428 encodes a type III effector (T3E) that shares 89.67% amino acid identity with Xanthomonas oryzae pv. oryzicola (Xoc) T3E AvrRxo1. Deletion of Xe4428 in the genome of X. euvesicatoria (strain Xcv85-10) compromised its virulence to infect pepper and Nicotiana benthamiana plants. Transient co-expression of Xe4428 and Rxo1 on pepper and N. benthamiana plant leaves results in a robust hypersensitive reaction. Thus, Xe4428, renamed as XeAvrRxo1, is a bona fide orthologue of XocAvrRxo1 that possesses both virulence and avirulence functions. Expression of XeAvrRxo1 in E. coli and X. euvesicatoria is toxic to both bacterial cells. Another X. euvesicatoria gene Xe4429, encodes a putative chaperone of XeAvrRxo1, which can interact with XeAvrRxo1 to suppress its toxicity in X. euvesicatoria and E. coli bacterial cells. Xe4429 also binds to the promoter region of XeavrRxo1 and represses its transcription/translation in X. euvesicatoria bacterial cells. In addition, expression of Xe4429 can enhance the secretion and translocation of XeAvrRxo1 into plant cells. Therefore, Xe4429 functions as an antitoxin, a transcription repressor, and a type III chaperone that is capable of enhancing the secretion and translocation of XeAvrRxo1 during pathogenesis.

pathology↗

bioRxiv2023

An oligodendrocyte silencer element underlies the pathogenic impact of lamin B1 structural variants

The role of non-coding regulatory elements and how they might contribute to tissue type specificity of disease phenotypes is poorly understood. Autosomal Dominant Leukodystrophy (ADLD) is a fatal, adult-onset, neurological disorder that is characterized by extensive CNS demyelination. Most cases of ADLD are caused by tandem genomic duplications involving the lamin B1 gene (LMNB1) while a small subset are caused by genomic deletions upstream of the gene. Utilizing data from recently identified families that carry LMNB1 gene duplications but do not exhibit demyelination, ADLD patient tissues, CRISPR modified cell lines and mouse models, we have identified a novel silencer element that is lost in ADLD patients and that specifically targets overexpression to oligodendrocytes. This element consists of CTCF binding sites that mediate three-dimensional chromatin looping involving the LMNB1 and the recruitment of the PRC2 repressor complex. Loss of the silencer element in ADLD identifies a previously unknown role for silencer elements in tissue specificity and disease causation.

genetics↗

bioRxiv2017

Elucidating the genetic architecture of reproductive ageing in the Japanese population

Population studies over the past decade have successfully elucidated the genetic architecture of reproductive ageing. However, those studies were largely limited to European ancestries, restricting the generalizability of the findings and overlooking possible key genes poorly captured by common European genetic variation. Here, in up to 67,029 women of Japanese ancestry, we report 26 loci (all P<5x10{macron}8) for puberty timing or age at menopause, representing the first loci for reproductive ageing in any non-European population. Highlighted genes for menopause include GNRH1, which supports a primary, rather than passive, role for hypothalamic-pituitary GnRH signalling in the timing of menopause. For puberty timing, we demonstrate an aetiological role for receptor-like protein tyrosine phosphatases by combining evidence across population genetics and pre- and peri-pubertal changes in hypothalamic gene expression in rodent and primate models. Furthermore, our findings demonstrate widespread differences in allele frequencies and effect estimates between Japanese and European populations, highlighting the benefits and challenges of large-scale trans-ethnic approaches.

genetics↗

bioRxiv2017

Mitochondrial impairment and rescue in riboflavin responsive neuropathy

Brown-Vialetto-Van Laere syndrome (BVVLS) represents a phenotypic spectrum of motor, sensory, and cranial nerve neuropathy, often with ataxia, optic atrophy and respiratory problems leading to ventilator-dependence. Loss-of-function mutations in two riboflavin transporter (RFVT) genes, SLC52A2 and SLC52A3, have recently been linked to BVVLS. However, the genetic frequency, neuropathology and downstream consequences of RFVT mutations have previously been undefined. By screening a large cohort of 132 patients with early-onset severe sensory, motor and cranial nerve neuropathy we confirmed the strong genetic link between RFVT mutations and BVVLS, identifying twenty-two pathogenic mutations in SLC52A2 and SLC52A3, fourteen of which were novel. Brain and spinal cord neuropathological examination of two cases with SLC52A3 mutations showed classical symmetrical brainstem lesions resembling pathology seen in mitochondrial disease, including severe neuronal loss in the lower cranial nerve nuclei, anterior horns and corresponding nerves, atrophy of the spinothalamic and spinocerebellar tracts and posterior column-medial lemniscus pathways. Mitochondrial dysfunction has previously been implicated in an array of neurodegenerative disorders. Since riboflavin metabolites are critical components of the mitochondrial electron transport chain (ETC), we hypothesized that reduced riboflavin transport would result in impaired mitochondrial activity, and confirmed this using in vitro and in vivo models. ETC complex I and complex II activity were decreased in SLC52A2 patient fibroblasts, while global knockdown of the single Drosophila RFVT homologue revealed reduced levels of riboflavin, downstream metabolites, and ETC complex I activity. RFVT knockdown in Drosophila also resulted in severely impaired locomotor activity and reduced lifespan, mirroring patient pathology, and these phenotypes could be partially rescued using a novel esterified derivative of riboflavin. Our findings indicate mitochondrial dysfunction as a downstream consequence of RFVT gene defects in BVVLS and validate riboflavin esters as a potential therapeutic strategy.

neuroscience↗