Biology subjects

Gravel, S.-P.

Publications and source records attributed to Gravel, S.-P..

6 recordsLinked to original sources

bioRxiv2025

Cyclic azapeptide cluster of differentiation-36 receptor modulator attenuates left ventricular injury and temporarily reduces long-chain fatty acid accumulation after myocardial ischemia-reperfusion in mice

Ischemic heart disease remains a leading global cause of death. We investigated the cardio-protective effects of the selective cluster of differentiation-36 receptor (CD36) modulator azapeptide MPE-298 in a mouse model of myocardial ischemia-reperfusion. Before reperfusion, a single intravenous dose of azapeptide MPE-298 reduced infarct size by 37% and transiently decreased left ventricular (LV) long-chain fatty acid (LCFA) accumulation, independently of saturation status. Metabolomic profiling revealed shifts in amino acids involved in energy production and antioxidant defense. Gene expression analysis showed transient modulation of oxidative stress and inflammation in both heart and adipose tissue. Modulation of CD36 by azapeptide MPE-298 exhibited therapeutic potential for treating acute myocardial ischemia and reperfusion by supporting metabolic recovery and limiting excess LCFA uptake. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=171 SRC="FIGDIR/small/674351v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@11aa899org.highwire.dtl.DTLVardef@132fc5borg.highwire.dtl.DTLVardef@55c32forg.highwire.dtl.DTLVardef@81585f_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2024

Lipid-based nanoparticles deliver mRNA to reverse the pathogenesis of lysosomal acid lipase deficiency in a preclinical model

Lysosomal acid lipase (LAL) is the only known enzyme that degrades cholesteryl esters (CEs) and triglycerides (TGs) in the lysosomes. LAL deficiency (LAL-D) results in hepatosplenomegaly with extensive accumulation of CEs and TGs, and can in the most severe cases be a life-threatening condition in early infancy. Using messenger ribonucleic acid (mRNA) for protein replacement is an innovative approach for the treatment of genetic disorders, but is challenged by a safe and efficient mRNA delivery. Here, we generated a combinatorial library of lipid-based nanoparticles (LNPs) for mRNA delivery and screened it in vitro and in vivo, which yielded a new formulation with a superior potency than an FDA-approved nanoformulation. This formulation efficiently delivered LAL mRNA and restored LAL activity in liver and spleen, mediating significant reversal of the pathological progression in an aggressive preclinical model of LAL-D. In vivo, the new formulation also promoted a more sustained and quantitatively higher LAL expression. In addition, repeated administration regimen mitigated hepatosplenomegaly, and targeted lipidomic analysis revealed strong diminution of CEs and TGs and of toxic lipid species in the liver and spleen. Transcriptomic analysis showed significant attenuation of inflammatory processes, fibrosis and several pathological pathways associated to LAL-D. These findings provide strong evidence that the intracellular production of LAL via mRNA-LNP is a very promising approach for the chronic treatment of LAL-D and support the clinical translation of mRNA therapy to overcome the challenges associated with traditional enzyme replacement therapies. One Sentence SummaryScreening of a mRNA-LNPs library yielded a formulation with outmost potency and mitigated the progression of LAL deficiency in a preclinical model.

bioengineering↗

bioRxiv2024

The Role of ATP Synthase Subunit e (ATP5I) in Mediating the Metabolic and Antiproliferative Effects of Biguanides

Here we identify the subunit e of F F -ATP synthase (ATP5I) as a target of metformin, a first-in-class antidiabetic biguanide. ATP5I maintains the stability of F F -ATP synthase dimers which is crucial for shaping cristae morphology. We demonstrate that ATP5I interacts with a biguanide analogue in vitro and disabling its expression by CRISPR-Cas9 in pancreatic cancer cells leads to the same phenotype as biguanide treated cells including mitochondrial morphology alterations, reduction of the NAD+/NADH ratio, inhibition of oxidative phosphorylation (OXPHOS), rescue of respiration by uncouplers and a compensatory increase in glycolysis. Notably, metformin affects the oligomerization of the F F -ATP synthase leading to accumulation of vestigial assembly intermediates also observed upon ATP5I inactivation. Moreover, ATP5I knockout (KO) cells exhibit resistance to the antiproliferative effects of biguanides, but reintroduction of ATP5I rescues the metabolic and anti-proliferative effects of metformin and phenformin. Finally, a genome-wide CRISPR screening in NALM-6 lymphoma cells revealed that metformin-treated cells exhibit genetic interaction profiles similar to those observed with the F F -ATP synthase inhibitor oligomycin, but not with the complex I inhibitor rotenone. This provides unbiased support for the relevance of the newly proposed target.

cancer biology↗

bioRxiv2024

Mitochondrial Signatures Shape Phenotype Switching and Apoptosis in Response to PLK1 and RSK Inhibitors in Melanoma

PLK1 inhibitors are emerging anti-cancer agents being tested in monotherapy and combination therapies for various cancers. Although PLK1 inhibition in experimental models shows potent antitumor effects, translation to the clinic has been hampered by low antitumor activity and tumor relapse. Here, we report the identification of mitochondrial protein signatures that determine sensitivity to approaches targeting PLK1 in human melanoma cell lines. In response to PLK1 inhibition or gene silencing, resistant cells adopt a pro-inflammatory and dedifferentiated phenotype, while sensitive cells engage apoptosis. Mitochondrial DNA depletion and silencing of the ABCD1 transporter sensitize cells to PLK1 inhibition and attenuate the associated pro-inflammatory response. We also found that non-selective inhibitors of the p90 ribosomal S6 kinase (RSK) exert their anti-proliferative and pro-inflammatory effects via PLK1 inhibition. This work reveals overlooked impacts of PLK1 on phenotype switching and suggests that mitochondrial precision medicine can help improve response to targeted therapies.

cancer biology↗

bioRxiv2024

Early IKKb-dependent anabolic signature governs vascular smooth muscle cells fate and abdominal aortic aneurysm development

BackgroundAbdominal aortic aneurysm (AAA) is a detrimental disease with no effective pharmacological therapy. While inflammation is recognized as one of the key regulators of AAA, targeting inflammatory pathways once the disease is established does not impact the outcomes. However, understanding the earliest molecular indicators could shed light on the precise biological targets and prognostic markers for AAA. MethodsUsing apolipoprotein E (ApoE)-deficient mice fed with a standard diet and infused with Angiotensin II (Ang II), we conducted bulk RNA-sequencing (RNA-Seq) analysis on suprarenal (SRA) regions obtained from both unchallenged and challenged WT mice, specifically examining responses 24 hours after Ang II infusion to capture the initial phases of aortic stress response. We further created a unique model of hyperlipidemic mice in which the expression of the inhibitor of nuclear factor kappa B kinase subunit beta (IKK{beta}) can be conditionally (via tamoxifen injection) suppressed in vascular smooth muscle cells (VSMC). The development of AAA was evaluated using in situ examination and quantified using RT-qPCR, immunohistochemistry and fluorescence microscopy. Cultured VSMC were exposed to the selective IKK{beta} inhibitor MLN120b and the expression levels of phenotypic markers kruppel like factor 4 (KLF4), {beta}-Catenin and cellular communication network factor 2 (CCN2) were addressed using cellular extracts and immunoblot analysis. ResultsRNA-Seq data support the presence of early anabolic events in SRA regions detailing activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway, which paralleled cellular anabolic processes including mitochondria, ribosome and sterol biosynthesis, the Unfolded Protein Response (UPR) and fibrogenesis. Conditional deletion of the Ikbkb gene in VSMC significantly reduces the incidence of SRA lesions as well as the rate of aneurysm ruptures in mice exposed to Ang II. In situ analysis further demonstrated that the protection conferred by the lack of IKK{beta} expression in VSMC is associated with reduced inflammatory response, the preservation of the contractile over the degradative VSMC phenotypes, and the absence of an anabolic signature. ConclusionOur results not only reinforce the major roles played by VSMC in the rapid adaptation leading to the deleterious remodeling of the vascular wall and aortic lesions but also support a paradigm aiming at repositioning the efforts focusing on anabolic rather than inflammatory events.

molecular biology↗

bioRxiv2017

Translational and HIF1α-dependent metabolic reprograming underpin oncometabolomeplasticity and synergy between oncogenic kinase inhibitors and biguanides.

There is heightened interest to devise therapies that target the oncometabolome. We show that kinase inhibitors (KIs) and biguanides synergistically target melanoma, leukemia, and breast, colon and renal cancer cells, but not non-transformed cells. Metabolic profiling confirmed opposing effects of KIs and biguanides on glycolysis, but this was insufficient to explain the observed synergy between the drugs. Rather, we define a critical role for the synthesis of non-essential amino acids (NEAA) aspartate, asparagine and serine as well as reductive glutamine metabolism, in determining the sensitivity of cancer cells to KI - biguanide combinations. The mTORC1/4E-BP axis regulates aspartate, asparagine and serine synthesis by modulating translation of mRNAs encoding PC, ASNS, PHGDH and PSAT1. Ablation of 4E-BP1 and 2 results in a dramatic increase in serine, aspartate and asparagine levels and a substantial decrease in sensitivity of breast cancer and melanoma cells to KI - biguanide combinations. In turn, efficacy of KI - biguanide combinations is impeded by HIF1 and sustained reductive glutamine metabolism. These findings identify hitherto unappreciated translational reprograming of NEAA synthesis and HIF1-dependent stimulation of reductive glutamine metabolism as critical metabolic vulnerabilities of cancer that underpin synergy between KIs and biguanides.

cancer biology↗