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Biology subjects

Boya, P.

Publications and source records attributed to Boya, P..

5 recordsLinked to original sources

Mitochondria-Lysosomes Crosstalk Shapes Neonatal Metabolic Transition in Neonatal Enterocytes

The neonatal gastrointestinal tract mediates nutrient absorption and the establishment of immune tolerance to commensal microbiota. In early life, lysosome-rich enterocytes (LREs) in the ileum are necessary for the intracellular digestion of maternal milk proteins. However, the molecular mechanisms sustaining their function remain incompletely characterized. Here, we demonstrate that LRE mitochondrial homeostasis and autophagic capacity are critical for efficient nutrient uptake and maintenance of their specialized identity, as disruption of either process leads to premature differentiation into post-weaning enterocytes (PECs) with diminished endolysosomal and metabolic activity. Transcriptomic profiling further revealed that neonatal LREs exhibit a distinctive antioxidant signature, which preserves redox balance and safeguards the expression of the transcriptional regulators MAFB and BLIMP1, both central repressors of the neonatal-to-adult metabolic transition. These findings establish the mitochondria-lysosome axis as a key determinant of LRE function and neonatal metabolic programming. They also provide a mechanistic framework for understanding how organelle dysfunction and redox imbalance may contribute to early-life malnutrition syndromes, such as Kwashiorkor, and suggest therapeutic strategies aimed at preserving mitochondrial and lysosomal integrity.

developmental biology↗

The developing retina undergoes mitochondrial remodeling via PINK1/PRKN-dependent mitophagy

Mitophagy, the selective degradation of mitochondria, is essential for retinal ganglion cell (RGC) differentiation and retinal homeostasis. However, the specific mitophagy pathways involved and their temporal dynamics during retinal development and maturation remain poorly understood. Using proteomics analysis of isolated mouse retinas across developmental stages and the mitophagy reporter mouse line, mito-QC, we characterized mitophagy throughout retinogenesis. While mitolysosomes were more prevalent in the mature retina, we observed two distinct mitophagy peaks during embryonic development. The first, independent of PTEN-induced kinase 1 (PINK1) activation, was associated with RGCs. The second, PINK1-dependent peak was triggered after an increase in retinal oxidative stress. This PINK1-dependent, oxidative stress-induced mitophagy pathway is conserved in mice and zebrafish, providing the first evidence of programmed, PINK1-dependent mitophagy during development.

developmental biology↗

Ambra1 haploinsufficiency results in metabolic alterations and exacerbates age-associated retinal degeneration

Autophagy is a key process in the maintenance of cellular homeostasis. The age-dependent decline in retinal autophagy has been associated with photoreceptor degeneration. Retinal dysfunction can also result from damage to the retinal pigment epithelium (RPE), as the RPE-retina constitutes an important metabolic ecosystem that must be finely tuned to preserve visual function. While studies of mice lacking essential autophagy genes have revealed a predisposition to retinal degeneration, the consequences of a moderate reduction in autophagy, similar to that which occurs during physiological aging, remain unclear. Here, we describe a retinal phenotype consistent with accelerated aging in mice carrying a haploinsufficiency for Ambra1, a pro-autophagic gene. These mice show protein aggregation in the retina and RPE, metabolic underperformance, and premature vision loss. Moreover, Ambra1+/gt mice are more prone to retinal degeneration after RPE stress. These findings indicate that autophagy provides crucial support to RPE-retinal metabolism and protects the retina against stress and physiological aging.

cell biology↗

Microglial phagocytosis dysfunction during stroke is prevented by rapamycin

Microglial phagocytosis is rapidly emerging as a therapeutic target in neurodegenerative and neurological disorders. An efficient removal of cellular debris is necessary to prevent buildup damage of neighbor neurons and the development of an inflammatory response. As the brain professional phagocytes, microglia are equipped with an array of mechanisms that enable them to recognize and degrade several types of cargo, including neurons undergoing apoptotic cell death. While microglia are very competent phagocytes of apoptotic cells under physiological conditions, here we report their dysfunction in mouse and monkey (Macaca fascicularis and Callithrix jacchus) models of stroke by transient occlusion of the medial cerebral artery (tMCAo). The impairment of both engulfment and degradation was related to energy depletion triggered by oxygen and nutrients deprivation (OND), which led to reduced process motility, lysosomal depletion, and the induction of a protective autophagy response in microglia. Basal autophagy, which is in charge of removing and recycling intracellular elements, was critical to maintain microglial physiology, including survival and phagocytosis, as we determined both in vivo and in vitro using knock-out models of autophagy genes and the autophagy inhibitor MRT68921. Notably, the autophagy inducer rapamycin partially prevented the phagocytosis impairment induced by tMCAo in vivo but not by OND in vitro. These results suggest a more complex role of microglia in stroke than previously acknowledged, classically related to the inflammatory response. In contrast, here we demonstrate the impairment of apoptotic cell phagocytosis, a microglial function critical for brain recovery. We propose that phagocytosis is a therapeutic target yet to be explored and provide evidence that it can be modulated in vivo using rapamycin, setting the stage for future therapies for stroke patients.

neuroscience↗

HDAC inhibition ameliorates cone survival in retinitis pigmentosa mice

Cone photoreceptor cell death in inherited retinal diseases, such as Retinitis Pigmentosa (RP), leads to the loss of high acuity and color vision and ultimately to blindness. In RP, a vast number of mutations perturb the structure and function of rod photoreceptors while cones remain initially unaffected. Cone death follows rod death secondarily due to increased oxidative stress, inflammation, and loss of structural and nutritional support provided by rods. Here, we show that secondary cone cell death in animal models for RP was associated with an increased activity of histone deacetylates (HDACs). A single intravitreal injection of an HDAC inhibitor at a late stage of the disease, when majority of rods have already degenerated, was sufficient to delay cone death and support long-term cone survival. Moreover, the surviving cones remained light sensitive and initiated light-driven ganglion cell responses. RNA-seq analysis of protected cones demonstrated that HDAC inhibition led to multi-level protection via regulation of different pro-survival pathways, including MAPK, PI3K-Akt, and autophagy. This study suggests a unique possibility for a targeted pharmacological protection of both primary degenerating rods and secondary dying cones by HDAC inhibition and creates hope to maintain vision in RP patients independent of the disease stage.

neuroscience↗