Loss of LAT1 sex-dependently delays recovery after caerulein-induced acute pancreatitis.

BACKGROUND: The expression of amino acid transporters is known to vary during acute pancreatitis (AP) except for LAT1 (slc7a5), the expression of which remains stable. LAT1 supports cell growth by importing leucine and thereby stimulates mammalian target of rapamycin (mTOR) activity, a phenomenon often observed in cancer cells. The mechanisms by which LAT1 influences physiological and pathophysiological processes and affects disease progression in the pancreas are not yet known. AIM: To evaluate the role of LAT1 in the development of and recovery from AP. METHODS: AP was induced with caerulein (cae) injections in female and male mice expressing LAT1 or after its knockout (LAT1 Cre/LoxP). The development of the initial AP injury and its recovery were followed for seven days after cae injections by daily measuring body weight, assessing microscopical tissue architecture, mRNA and protein expression, protein synthesis, and enzyme activity levels, as well as by testing the recruitment of immune cells by FACS and ELISA. RESULTS: The initial injury, evaluated by measurements of plasma amylase, lipase, and trypsin activity, as well as the gene expression of dedifferentiation markers, did not differ between the groups. However, early metabolic adaptations that support regeneration at later stages were blunted in LAT1 knockout mice. Especially in females, we observed less mTOR reactivation and dysfunctional autophagy. The later regeneration phase was clearly delayed in female LAT1 knockout mice, which did not regain normal expression of the pancreas-specific differentiation markers recombining binding protein suppressor of hairless-like protein (rbpjl) and basic helix-loop-helix family member A15 (mist1). Amylase mRNA and protein levels remained lower, and, strikingly, female LAT1 knockout mice presented signs of fibrosis lasting until day seven. In contrast, pancreas morphology had returned to normal in wild-type littermates. CONCLUSION: LAT1 supports the regeneration of acinar cells after AP. Female mice lacking LAT1 exhibited more pronounced alterations than male mice, indicating a sexual dimorphism of amino acid metabolism.

The effect of an HIV-1 viral protease inhibitor on staurosporine-induced apoptosis in immortalized mesangial cells

CONTEXT: Progressive glomerular sclerosis is a condition characterized by the accumulation of glomerular extracellular matrix and a decrease in the number of glomerular cells. The mechanisms involved in the progressive loss of glomerular cells are not well understood but may involve the process of apoptosis. The principal mediators for the apoptotic pathway are a class of protease enzymes called caspases. It is not known how other therapeutic protease inhibitors affect the caspase cascade and therefore whether they would be effective in preventing excessive apoptosis in the late stages of progressive glomerular sclerosis. OBJECTIVE: To evaluate whether an inhibitor of the HIV-1 viral protease Ac-Leu-Val-phenylalanine (PI) could inhibit apoptosis in immortalized mesangial cells. DESIGN: Experimental. SETTING: Nephrology Division, Universidade Federal de Säo Paulo/Escola Paulista de Medicina. PARTICIPANTS: Immortalized mesangial cells. PROCEDURES: Cell culture. MAIN MEASUREMENTS: Viability and rate of apoptosis. RESULTS: Immortalized mesangial cells were treated with staurosporine (at concentrations of 10-100 nM for 8-28 hours) to induce apoptosis. Staurosporine at 10 nM for 8 hours had no effect on viability, but did cause a significant increase in the rate of apoptosis (p = 0.0411, n = 6). Increasing the incubation time elicited a greater increase in the rate of apoptosis (p = 0.0001, n = 6), although there was also a significant decrease in viability (p=0.0002). Increasing the concentration of staurosporine to 100 nM resulted in a marked increase in apoptosis (p <0.0001) but resulted in unacceptable viability (<40 percent, p <0.0001, n = 6). CONCLUSIONS: Incubation of immortalized mesangial cells with PI (900 nM) alone for 2-24 hours had no effect on cell viability or the rate of apoptosis when compared with vehicle (methanol) controls. Co-incubation of the cells with staurosporine (10 nM) and PI for 24 hours had no significant effect on the rate of apoptosis. Therefore, in immortalized mesangial cells, staurosporine-induced apoptosis was not significantly affected by the HIV-1 viral protease inhibitor Ac-Leu-Val-phenylalanine

Mecanismos celulares e moleculares da nefrotoxicidade pela cisplatina / Cellular and molecules mechanism of the nephrotoxicity at cisplatin

A cisplatina é um antineoplástico amplamente utilizado na quimioterapia de tumores, aumentando a sobrevida ou mesmo promovendo a cura do paciente. O seu principal efeito colateral é a nefrotoxicidade. Os mecanismos desse efeito adverso ainda näo säo bem conhecidos, podendo estar relacionados à apoptose, necrose, peroxidaçäo lipídica e aumento da concentraçäo de cálcio intracelular. A presente revisäo tem por objetivo colaborar para o conhecimento dessa faceta da cisplatina, condiçäo imprescindível para a formulaçäo de esquemas terapêuticos que atenuem a lesäo renal, sem comprometer a eficácia dessa importante droga.(au)

Nefrotoxicidade e morte celular (apoptose ou necrose) induzida pela cisplatina ao longo do néfron / Nefrotoxicitity and celular death (apoptosis or necrosis) induced by cisplatin along or nephron

A nefrotoxicidade é o fator limitante do antineoplásico cisplatina. Pelo fato de que a cisplatina afeta porções distintas do néfron, investigamos o efeito de duas concentrações de cisplatina (l ou lOOmM) em quatro linhagens diferentes de células: células mesangiais (CMI), células tubulares proximais (LLC-PKl), células tubulares distais (MDCK) e células de ducto coletor de medula interna (IMCD). O corante fluorescente para núcleos Hoechst 33342 foi empregado para quantificar as taxas de apoptose ( por cento), a eletroforese de DNA em gel de agarose, o método de TUNEL e a citometria de fluxo foram também utilizados. O método de exclusão utilizando acridina orange e brometo de etídeo foi utilizado para avaliar a viabilidade celular ( por cento). A viabilidade das células CMI diminuiu com a cisplatina 100 mM após 24 h (43,7ñ5,1/ 24 h; médiañEPM, *p