Biology subjects

Berenguer, I.

Publications and source records attributed to Berenguer, I..

4 recordsLinked to original sources

bioRxiv2023

LOSS OF CLDN5 -AND INCREASE IN IRF7- IN THE HIPPOCAMPUS AND CEREBRAL CORTEX OF DIABETIC MICE AT THE EARLY SYMPTOMATIC STAGE.

Analyzing changes in gene expression within specific brain regions of individuals with Type 2 Diabetes (T2DM) who do not exhibit significant cognitive deficits can yield valuable insights into the mechanisms that may underlie the progression toward a more severe phenotype, for example as when individuals age. Here, we present evidence that adult mice with long-term type 2 diabetes mellitus (T2DM) and minor cognitive deficits display alterations in the expression of 27 genes in the cerebral cortex and 16 genes in the hippocampus compared to non-T2DM mice. Only six of these genes undergo the same type of change both in the cortex and hippocampus: Interferon regulatory factor 7 (Irf7), Hypoxia-inducible factor 3 alpha (Hif-3), period circadian clock 2 (Per2), xanthine dehydrogenase (Xdh), and Transforming growth factor {beta}-stimulated clone 22/TSC22 (Tscd3) are all upregulated, while Claudin-5 (Cldn5) is downregulated. At the protein level, Claudin5 and IRF7 showed equivalente changes: downregulation of CLDN5 and upregulation of IRF7. These results suggest that cognitive deficits linked to chronic T2DM may stem from compromised blood-brain barrier integrity and an abnormal inflammatory response in the early stages of the disease. This underscores the potential for therapeutic interventions targeting CLDN5 and IRF7.

neuroscience↗

bioRxiv2023

The organotypic culture of mouse seminiferous tubules as a reliable methodology for the study of meiosis in vitro

Male mouse meiosis has been traditionally studied using descriptive methods like histological sections, spreading or squashing techniques, which allow the observation of fixed meiocytes in either wildtype or genetically modified mice. For these studies, the sacrifice of the males and the extraction of the testicles are required to obtain the material of study. Other functional in vivo studies include the administration of intravenous or intraperitoneal drugs, or the exposure to mutagenic agents or generators of DNA damage, in order to study their impact on meiosis progression. However, in these studies, the exposure times or drug concentration are important limitations to consider when acknowledging animal welfare. Recently, several approaches have been proposed to offer alternative methodologies that allow the in vitro study of spermatocytes with a considerable reduction in the use of animals. Here we revisit and validate an optimal technique of organotypic culture of fragments of seminiferous tubules for meiotic studies. This technique is a trustable methodology to develop functional studies that preserve the histological configuration of the seminiferous tubule, aim homogeneity of the procedures (the use of the same animal for different study conditions), and allow procedures that would compromise the animal welfare. Therefore, this methodology is highly recommendable for the study of meiosis and spermatogenesis, while it supports the principle of 3R's for animal research.

cell biology↗

bioRxiv2021

Haspin participates in Aurora phosphorylation at centromeres and contributes to chromosome congression in male mouse meiosis

Chromosome segregation requires that centromeres properly attach to spindle microtubules. This is an essential step towards the accuracy of cell division and therefore must be precisely regulated in both mitosis and meiosis. One of the main centromeric regulatory signaling pathways is the Haspin-H3T3ph-chromosomal passenger complex (CPC) cascade, which is responsible for the recruitment of the CPC to the centromeres. In mitosis, Haspin kinase phosphorylates H3 at threonine 3 (H3T3ph), the essential histone mark that recruits the CPC whose catalytic component is Aurora B kinase. To date, no data has yet been presented about the action of the centromeric Haspin-H3T3ph-CPC pathway in mammalian male meiosis. We have analyzed the consequences of Haspin chemical inhibition in cultured spermatocytes using LDN-192960. Our in vitro studies suggest that Haspin kinase activity is required for proper chromosome congression during both meiotic divisions and for the recruitment of phosphorylated Aurora B at meiotic centromeres. These results have been confirmed by the characterization of the meiotic phenotype of the genetic mouse model Haspin-/-, which displays similar defects. In addition, our work demonstrates that the absence of H3T3ph histone mark does not alter SGO2 localization to meiotic centromeres. These results add new and relevant information regarding the regulation of centromere function during meiosis.

cell biology↗

bioRxiv2019

PDS5 proteins regulate the length of axial elements and telomere integrity during male mouse meiosis

Cohesin cofactors regulate the loading, maintenance and release of cohesin complexes from chromosomes during the mitotic cell cycle but little is known on their role during vertebrate meiosis. One such cofactor is PDS5, which exists in two versions in somatic and germline cells, PDS5A and PDS5B, with unclear functional specificity. Here we have analyzed their distribution and functions in mouse spermatocytes. We show that simultaneous elimination of PDS5A and PDS5B results in severe defects during prophase I while their individual depletion does not, suggesting a functional redundancy of the two factors. Shortened axial/lateral elements and a reduction of early recombination nodules are observed in the absence of both PDS5 proteins. Moreover, telomere integrity and their association to the nuclear envelope are severely compromised. As these defects occur without detectable reduction in chromosome-bound cohesin, we propose that the dynamic behavior of the complex, mediated by PDS5 proteins, is key for successful completion of meiotic prophase I.

cell biology↗