LAMA2-congenital muscular dystrophy (LAMA2-CMD) is a neuromuscular disease which manifests itself from birth and is caused by mutations in the LAMA2 gene. Although most studies have focused on the role of LAMA2 in skeletal muscle, LAMA2 is also expressed in other organs. Preliminary data from the host laboratory suggests that the absence of LAMA2 may lead to increased oxidative stress and alterations in cell metabolism in organs such as the kidney and liver. Therefore, this project aimed at addressing how the kidney and liver are affected during the onset of LAMA2-CMD, specifically between embryonic days 17.5 and 18.5 (E17.5 and E18.5), using the dyW mouse model for LAMA2- CMD. To explore how Lama2 deficiency affects organ homeostasis, pathways linked to oxidative stress, mitochondria stability and glucose metabolism were analysed in order to compare between livers or kidneys of WT and dyW mice at E17.5 and E18.5. Alterations in oxidative stress response were detected in the liver and kidney at E17.5 and E18.5, with impaired mitochondrial function in dyW kidneys. Considering that the alterations were more predominant in the kidney, primary proximal tubule cells were isolated from WT and dyW foetuses, to further dissect the impact of Lama2 deficiency in this organ. In vitro results showed no differences between WT and dyW kidney cells. While this work highlighted significant alterations in oxidative stress in vivo, particularly in the kidney, likely given its higher Lama2 expression, the Lama2 deficiency alone may not fully account for the alterations seen in the whole organs of these animals, and these effects may diminish outside the in vivo context. Overall, this project sheds new light into the mechanisms that link LAMA2 to cell homeostasis which may vary depending on the type of organ and their intrinsic expression of LAMA2.

Tese de mestrado, Biologia Evolutiva e do Desenvolvimento, 2024, Universidade de Lisboa, Faculdade de Ciências