AUTHOR=Bea-Mascato Brais , Neira-Goyanes Elena , Iglesias-Rodríguez Antía , Valverde Diana 

TITLE=Depletion of ALMS1 affects TGF-β signalling pathway and downstream processes such as cell migration and adhesion capacity

JOURNAL=Frontiers in Molecular Biosciences

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/molecular-biosciences/articles/10.3389/fmolb.2022.992313

DOI=10.3389/fmolb.2022.992313

ISSN=2296-889X

ABSTRACT=<p><bold>Background:</bold><italic>ALMS1</italic> is a ubiquitous gene associated with Alström syndrome (ALMS). The main symptoms of ALMS affect multiple organs and tissues, generating at last, multi-organic fibrosis in the lungs, kidneys and liver. TGF-β is one of the main pathways implicated in fibrosis, controlling the cell cycle, apoptosis, cell migration, cell adhesion and epithelial-mesenchymal transition (EMT). Nevertheless, the role of <italic>ALMS1</italic> gene in fibrosis generation and other implicated processes such as cell migration or cell adhesion <italic>via</italic> the TGF- β pathway has not been elucidated yet.</p><p><bold>Methods:</bold> Initially, we evaluated how depletion of <italic>ALMS1</italic> affects different processes like apoptosis, cell cycle and mitochondrial activity in HeLa cells. Then, we performed proteomic profiling with TGF-β stimuli in HeLa <italic>ALMS1</italic> −/− cells and validated the results by examining different EMT biomarkers using qPCR. The expression of these EMT biomarkers were also studied in hTERT-BJ-5ta <italic>ALMS1</italic> −/−. Finally, we evaluated the SMAD3 and SMAD2 phosphorylation and cell migration capacity in both models.</p><p><bold>Results:</bold> Depletion of <italic>ALMS1</italic> generated apoptosis resistance to thapsigargin (THAP) and C2-Ceramide (C2-C), and G2/M cell cycle arrest in HeLa cells. For mitochondrial activity, results did not show significant differences between <italic>ALMS1 +/+</italic> and <italic>ALMS1 −/−</italic>. Proteomic results showed inhibition of downstream pathways regulated by TGF-β. The protein-coding genes (PCG) were associated with processes like focal adhesion or cell-substrate adherens junction in HeLa. <italic>SNAI1</italic> showed an opposite pattern to what would be expected when activating the EMT in HeLa and BJ-5ta. Finally, in BJ-5ta model a reduced activation of SMAD3 but not SMAD2 were also observed. In HeLa model no alterations in the canonical TGF-β pathway were observed but both cell lines showed a reduction in migration capacity.</p><p><bold>Conclusion:</bold><italic>ALMS1</italic> has a role in controlling the cell cycle and the apoptosis processes. Moreover, the depletion of <italic>ALMS1</italic> affects the signal transduction through the TGF-β and other processes like the cell migration and adhesion capacity.</p>