Bcl-2 family proteins reorganize mitochondrial membranes during apoptosis, to form pores and rearrange cristae. In vitro and in vivo analysis integrated with human genetics reveals a novel homeostatic mitochondrial function for Bcl-2 family protein Bid. Loss of full-length Bid results in apoptosis-independent, irregular cristae with decreased respiration. Bid-/- mice display stress-induced myocardial dysfunction and damage. A gene-based approach applied to a biobank, validated in two independent GWAS studies, reveals that decreased genetically determined BID expression associates with myocardial infarction (MI) susceptibility. Patients in the bottom 5% of the expression distribution exhibit >4 fold increased MI risk. Carrier status with nonsynonymous variation in Bid's membrane binding domain, BidM148T, associates with MI predisposition. Furthermore, Bid but not BidM148T associates with Mcl-1Matrix, previously implicated in cristae stability; decreased MCL-1 expression associates with MI. Our results identify a role for Bid in homeostatic mitochondrial cristae reorganization, that we link to human cardiac disease.
The authors declare that all relevant data are available within the article and its supplementary information files. Publicly available data on coronary artery disease / myocardial infarction have been contributed by CARDIoGRAMplusC4D investigators and have been downloaded from www.CARDIOGRAMPLUSC4D.ORG.GTEx Consortium (v6p) transcriptome/genotype data is available through the GTEx portal (htt://www.gtexportal.org) and through dpGap (GTEx Consortium, Nature 2017). Due to the GTEx Consortium's donor consent agreement, the raw data and attributes which may be used to identify the participants are not publicly available. Requests for access can be made through the dbGaP: https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?study_id=phs000424.v6.p1 and are assessed bu a Data Access Committee (National Human Genome Research Institute; nhgridac@mail.nih.gov). The summary statistics results for eQTL data (v6p) are available through the GTEx portal: https://gtexportal.org/home/datasets.Investigators may obtain access to UK Biobank data through an application process: http://www.ukbiobank.ac.uk/register-apply/. The registration is then reviewed by the Access Management Team of the UK Biobank. Genome-wide association studies summary statistics results are publicly available: http://www.nealelab.is/blog/2017/7/19/rapid-gwas-of-thousands-of-phenotypes-for-337000-samples-in-the-uk-biobankModel definition files are described in Gamazon et al. 2015. Code for the following analyses is publicly available: PrediXcan: https://github.com/hakyimlab/PrediXcan S-PrediXcan: https://github.com/hakyimlab/MetaXcan
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All mice were housed and experiments performed with approval by the IACUC Protocol # M1600037, M1600220, M/14/231, and # V-17-001 of Vanderbilt University Medical Center and the Tennessee Valley VA in compliance with NIH guidelines.
© 2018, Salisbury-Ruf et al.
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Niemann–Pick disease type C (NPC) is a devastating lysosomal storage disease characterized by abnormal cholesterol accumulation in lysosomes. Currently, there is no treatment for NPC. Transcription factor EB (TFEB), a member of the microphthalmia transcription factors (MiTF), has emerged as a master regulator of lysosomal function and promoted the clearance of substrates stored in cells. However, it is not known whether TFEB plays a role in cholesterol clearance in NPC disease. Here, we show that transgenic overexpression of TFEB, but not TFE3 (another member of MiTF family) facilitates cholesterol clearance in various NPC1 cell models. Pharmacological activation of TFEB by sulforaphane (SFN), a previously identified natural small-molecule TFEB agonist by us, can dramatically ameliorate cholesterol accumulation in human and mouse NPC1 cell models. In NPC1 cells, SFN induces TFEB nuclear translocation via a ROS-Ca2+-calcineurin-dependent but MTOR-independent pathway and upregulates the expression of TFEB-downstream genes, promoting lysosomal exocytosis and biogenesis. While genetic inhibition of TFEB abolishes the cholesterol clearance and exocytosis effect by SFN. In the NPC1 mouse model, SFN dephosphorylates/activates TFEB in the brain and exhibits potent efficacy of rescuing the loss of Purkinje cells and body weight. Hence, pharmacological upregulating lysosome machinery via targeting TFEB represents a promising approach to treat NPC and related lysosomal storage diseases, and provides the possibility of TFEB agonists, that is, SFN as potential NPC therapeutic candidates.
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