Microglia mitochondrial complex I deficiency during development induces glial dysfunction and early lethality.

Primary mitochondrial diseases (PMDs) are associated with pediatric neurological disorders and are traditionally related to oxidative phosphorylation system (OXPHOS) defects in neurons. Interestingly, both PMD mouse models and patients with PMD show gliosis, and pharmacological depletion of microglia, the innate immune cells of the brain, ameliorates multiple symptoms in a mouse model. Given that microglia activation correlates with the expression of OXPHOS genes, we studied whether OXPHOS deficits in microglia may contribute to PMDs. We first observed that the metabolic rewiring associated with microglia stimulation in vitro (via IL-33 or TAU treatment) was partially changed by complex I (CI) inhibition (via rotenone treatment). In vivo, we generated a mouse model deficient for CI activity in microglia (MGcCI). MGcCI microglia showed metabolic rewiring and gradual transcriptional activation, which led to hypertrophy and dysfunction in juvenile (1-month-old) and adult (3-month-old) stages, respectively. MGcCI mice presented widespread reactive astrocytes, a decrease of synaptic markers accompanied by an increased number of parvalbumin neurons, a behavioral deficit characterized by prolonged periods of immobility, loss of weight and premature death that was partially rescued by pharmacologic depletion of microglia. Our data demonstrate that microglia development depends on mitochondrial CI and suggest a direct microglial contribution to PMDs.

Efecto de la Vitamina E en Células Peritubulares de Testículos de Ratones Mus musculus Tratados con Ácido Valproico Durante el Estado Fetal y Pubertad / Effect of Vitamin E on Peritubular Cells from Testis of Mus musculus Mice Treated with Valproic Acid During the Fetal Stage and Puberty

El ácido valproico (VPA) es un fármaco antiepiléptico teratógenico que, al ser administrado durante etapas tempranas del embarazo, puede producir alteraciones en el desarrollo embriofetal, las que se manifiestan tanto a nivel del sistema nervioso como del testículo. No obstante, se ha reportado que la administración de vitamina E (VE) podría revertir dichas alteraciones. El objetivo del presente estudio fue determinar el efecto protector de la VE a nivel testicular en fetos y ratones púberes expuestos a VPA durante la fase embrionaria de su desarrollo. Se utilizó un total de 30 ratones hembra adultas gestantes (Mus musculus) cepa BALB/c, las cuales se dividieron en 6 grupos. El estudio contempló el análisis de fetos machos a los 17,5 días post-coital (dpc) y machos juveniles a las 6 semanas post-natal. A los grupos 1 y 4 se les administró 0,3 mL de solución fisiológica (grupos control para 17,5 dpc y 6 semanas postnatal, respectivamente). A los grupos 2 y 5 se les suministró la cantidad de 600 mg/kg de VPA (grupos VPA), en tanto que a los grupos 3 y 6 se les aplicó la misma dosis de VPA complementada con 200 UI de VE (grupos VPA+VE). Se describió la histología normal y patológica del compartimento peritubular del testículo. En los grupos VPA se evidenció una degeneración de la pared peritubular, y atrofia de túbulos seminíferos, así como exfoliación de las células germinales. Por el contrario, en los grupos VPA+VE tales signos no fueron observados y la morfología presentó aspecto normal solo con algunas alteraciones focales. Estos resultados corroboran el hecho que la administración de VE contrarresta en parte, los efectos deletéreos que ocasiona el VPA.

SUMMARY: Valproic acid (VPA) is a teratogenic antiepileptic drug that, when administered during the early stages of pregnancy, can produce alterations in embryo-fetal development, which manifest both at the level of the nervous system and the testicle. However, it has been reported that the administration of vitamin E (VE) could reverse these alterations. The study aimed to determine the protective effect of VE at the testicular level in fetuses and pubertal mice exposed to VPA during the embryonic phase of their development. 30 pregnant adult female mice (Mus musculus) BALB/c strain were used, which were divided into 6 groups. The study included the analysis of male fetuses at 17.5 days post-coital (dpc) and juvenile males at 6 weeks post-natal. Groups 1 and 4 were administered 0.3 mL of physiological solution. Groups 2 and 5 were given 600 mg/kg of VPA (VPA groups), while groups 3 and 6 were given the same dose of VPA supplemented with 200 IU of VE (VPA+VE). The normal and pathological histology of the peritubular compartment of the testis was described. In the VPA groups, degeneration of the peritubular wall, and atrophy of the seminiferous tubules, as well as exfoliation of the germ cells, were evident. On the contrary, in the VPA+VE groups such signs were not observed and the morphology presented a normal appearance with only some focal alterations. These results corroborate the fact that the administration of VE partially counteracts the deleterious effects caused by VPA.