Biology subjects

Canales, M.

Publications and source records attributed to Canales, M..

6 recordsLinked to original sources

bioRxiv2026

High neuron-microglia interaction at the node of Ranvier predicts recovery in an inflammatory model of Multiple Sclerosis

Microglia, the resident immune cells of the central nervous system, dynamically respond to their environment in health, injury and disease. They contact axons at the nodes of Ranvier in an activity-dependent manner, a process which contributes to repair, but how adaptive immunity in Multiple Sclerosis (MS) impacts this neuron-microglia crosstalk remains unknown. Using an inflammatory MS model, we identify strengthened microglia-node interactions at remission onset, with marked interindividual variability. Increased engagement correlates with a Th2-related cytokine signature, and IL13/IL4 are sufficient to enhance microglia-node contacts. High interaction levels associate with more pro-regenerative microglia, improved tissue repair and better functional recovery. Low-intensity physical exercise at remission onset further promotes microglia-node interaction, pro-regenerative microglia and improves recovery. Consistently, high microglia-node contact in MS tissue is associated with more extensive remyelination, underscoring this interaction as a key process in repair.

neuroscience↗

bioRxiv2024

KIR3DL1 and Tox identify clonally expanded encephalitogenic neuron-specific CD8+ T cells in autoimmune encephalitis

Autoreactive CD8+ T cells are the principal suspects in autoimmune encephalitis (AIE) with antibodies targeting intracellular neuronal antigens So far, the search for neuron-autoreactive CD8+ T cells has been focused on a few autoantigens and did not yield convincing results. Here, we leveraged natural antigen presentation by hiPSC-derived neurons to look at the global autoreactive CD8+ T cell response, independently of pre-conceived hypothesis of the autoantigens involved in the disease. This unbiased approach allowed for the identification of rare polyclonal neuron-reactive CD8+ T cells in healthy donors, and contrastingly, expanded clonotypes in two patients with anti-Ri AIE. Detailed ex vivo phenotypic characterization of these clonotypes revealed a specific transcriptional program suggestive of a pathogenic potential. In particular, this subset can be identified by the expression of KIR3DL1 and TOX. Strikingly, we could also demonstrate that CD8+ T cells found in the brain of an anti-Ri AIE patient display a similar phenotype associated with cytotoxicity and encephalitogenic features.

immunology↗

bioRxiv2024

Human stem cell derived neurons and astrocytes to detect auto-reactive IgG in neurological diseases

Background and objectivesUp to 46% of patients with presumed autoimmune limbic encephalitis are seronegative for all currently known CNS antigens. We developed a cell-based assay (CBA) to screen for novel neural antibodies in serum and CSF using neurons and astrocytes derived from human induced pluripotent stem cells (hiPSC). MethodsHuman iPSC-derived astrocytes or neurons were incubated with serum/CSF from 99 patients (42 with inflammatory neurological diseases (IND) and 57 with non-IND (NIND)). The IND group included 11 patients with previously established neural antibodies, six with seronegative neuromyelitis optica spectrum disorder (NMOSD), 12 with suspected autoimmune encephalitis/paraneoplastic syndrome (AIE/PNS), and 13 with other IND (OIND). IgG binding to fixed CNS cells was detected using fluorescently-labelled antibodies and analyzed through automated fluorescence measures. IgG neuronal/astrocyte reactivity was further analyzed by flow cytometry. Peripheral blood mononuclear cells (PBMC) were used as CNS-irrelevant control target cells. Reactivity profile was defined as positive using a Robust regression and Outlier removal test with a false discovery rate at 10% following each individual readout. ResultsUsing our CBA, we detected antibodies recognizing hiPSC-derived neural cells in 19/99 subjects. Antibodies bound specifically to astrocytes in nine cases, to neurons in eight cases and to both cell types in two cases, as confirmed by microscopy single-cell analyses. Highlighting the significance of our novel 96-well CBA assay, neural-specific antibody binding was more frequent in IND (15/42) than in NIND patients (4/57) (Fisher test, p=0.0005). Three of three patients with astrocyte- reactive (2 AQP4+ NMO, 1 GFAP astrocytopathy), and 3/4 with intracellular neuron-reactive antibodies (2 Hu+, 1 Ri+ AIE/PNS), as identified in diagnostic laboratories, were also positive with our CBA. Most interestingly, we showed antibody-reactivity in 2/6 seronegative NMOSD, 6/12 probable AIE/PNS, and 1/13 OIND. Flow cytometry using hiPSC-derived CNS cells or PBMC detected antibody binding in 13 versus 0 patients, respectively, establishing the specificity of the detected antibodies for neural tissue. DiscussionOur unique hiPSC-based CBA allows for the screening of novel neuron-/astrocyte-reactive antibodies in patients with suspected immune-mediated neurological syndromes, and negative testing in established routine laboratories, opening new perspectives in establishing early diagnosis of such complex diseases.

neuroscience↗

bioRxiv2023

Unique proteomic signature of JCPyV-infected human astrocytes: from cells to extracellular vesicles

JC polyomavirus (JCPyV) is an opportunistic virus that remains in a latent state in the kidneys of more than half of the human adult population. In rare cases of severe immune suppression, the virus is able to establish a lytic infection of glial cells in the brain, resulting in a debilitating, demyelinating disease known as progressive multifocal leukoencephalopathy (PML). Because of the exceptional species and tissue specificity of the virus, appropriate models of JCPyV infection in the brain are lacking, thus hampering progress towards the development of novel antiviral strategies and biomarkers of disease activity. While PML has traditionally been characterized as a lytic infection of oligodendrocytes, more recent findings suggest an important role for astrocytes during the initial stages of disease. Here, using human induced pluripotent stem cell (hiPSC) derived-astrocytes coupled with a multiparametric approach, we show that 1. JCPyV readily infects and replicates in astrocytes, 2. JCPyV strongly dysregulates the cell biology and 3. these findings adequately reflect ex vivo findings. We perform an in-depth characterization of the effect of JCPyV on the cell proteome over time, demonstrating a strong dysregulation of the cell cycle and activation of the DNA damage response. Furthermore, we show that the proteomic signature observed for infected astrocytes is extended to excreted vesicles, underlining their potential to gain valuable insights into JCPyV propagation in the brain.

neuroscience↗

bioRxiv2021

Pericyte control of pancreatic islet blood flow impacts glucose homeostasis

The pancreatic islet depends on blood supply to efficiently sense plasma glucose levels and deliver insulin and glucagon into the circulation. Long thought to be passive conduits of nutrients and hormones, islet capillaries were recently found to be densely covered with contractile pericytes, suggesting local control of blood flow. Here we determined the contribution of islet pericytes to the regulation of islet blood flow, plasma insulin and glucagon levels, and glycemia. Selective optogenetic activation of pericytes in intraocular islet grafts contracted capillaries and diminished blood flow. In awake mice, acute clamping of islet blood flow by optogenetic or pharmacological activation of pericytes disrupted hormonal responses, glycemia, and glucose tolerance. Our findings indicate that pericytes mediate vascular responses in the islet that are required for adequate hormone secretion and glucose homeostasis. Vascular deficiencies commonly seen in the islets of people with type 2 diabetes may impair regulation of islet blood flow and thus precipitate islet dysfunction.

physiology↗

bioRxiv2018

Soil-transmitted helminthiasis in children of a rural community part of a school-based deworming program: a cross-sectional study in the Peruvian Amazon

BackgroundChildren in the Peruvian Amazon basin are at risk of soil-transmitted helminthiases (STH). The aim of this study was to determine the prevalence of STH (Ascaris lumbricoides, Trichuris trichiura, hookworm and Strongyloides stercoralis) in children from a rural community in the Peruvian Amazon and associated clinical, maternal, sanitation and hygiene factors associated. The community had an active school-based deworming program with mebendazole.\n\nMethodsA cross-sectional study was carried out in children aged 2-14 years in Iquitos, Peru; by parasitological analysis of their stools through five methods: direct smear examination, Kato-Katz, spontaneous sedimentation in tube, Baermann method modified by Lumbreras and agar plate culture. Mothers of the participating children were also invited to participate in the study. A questionnaire was completed by each participant to collect demographic and epidemiological information of interest.\n\nResultsAmong 124 children, 25.8% (32/124) had one or more STH. Prevalence of A. lumbricoides was 16.1% (20/124); S. stercoralis, 10.5% (13/124); hookworm, 1.6% (2/124) and T. trichiura, 1.6% (2/124). STH in mothers was higher in children with any STH than in children without any STH (36.4% vs 14.1%, p<0.02). Prevalence of the common STH (A. lumbricoides, T. trichiura and hookworm) was higher in children aged 2-5 than in older children (31.6% vs 12.8%; p=0.01). Several hygiene and sanitation deficits were identified; of which walking barefoot was significantly associated with STH infection (OR= 3.28; 95% CI= 1.11-12.07).\n\nConclusionsSTH are highly prevalent in children in this community; A. lumbricoides and S. stercoralis infections were the most frequent. Further studies should aim to understand the persistent high prevalence of common STH in endemic areas where massive drug administration is practiced, and to determine the appropriateness of controlling STH in mothers and S. stercoralis infection. Walking barefoot and other hygiene and sanitation conditions need to be addressed in this community.\n\nAUTHOR SUMMARYFew studies assessing soil-transmitted helminth infections in children and their risk factors have yet been conducted in the Peruvian Amazon. Even fewer reports exist from areas where mass drug administration programs have been initiated. In this study we provide insight to the frequency of soil-transmitted helminths in a setting with an ongoing school-based deworming program.\n\nBesides the most common soil-transmitted helminths (Ascaris lumbricoides, Trichuris trichiura and hookworm), we assessed the prevalence of Strongyloides stercoralis. Excluding the latter from intestinal helminths studies have often underestimate its frequency and impact in children.\n\nWe also surveyed for helminth infection in the mothers of the participating children as infection in caregivers could theoretically be associated with infection in children as they both may share same environmental and behavioral factors associated with STH infections. To our knowledge, this is the first Peruvian study assessing children and mother infection together.\n\nIn addition, our results highlight the suboptimal hygiene and sanitation conditions in which people from this rural community live. It likely represents the situation of other rural Amazonian communities in Peru. Public efforts are needed to provide these populations with dignified living conditions and to follow the equity global health agenda.

epidemiology↗