MOTS-c, a mitochondrial-derived peptide, ameliorates lysosomal membrane permeability and improves survival of soft tissue transplantation.
This study investigated whether the mitochondrial-derived peptide MOTS-c could improve survival of ischemic tissue flaps used in reconstructive surgery — a context where distal necrosis due to poor blood flow remains a significant clinical challenge. Using a rat ischemic flap model, researchers employed a broad range of techniques including RNA sequencing, tissue clearing, laser speckle contrast imaging, laser Doppler blood flow analysis, histological staining, Western blotting, ELISA, immunofluorescence, and adeno-associated virus (AAV)-mediated gene overexpression. The study also used human umbilical vein endothelial cells (HUVECs) for in vitro experiments. The authors report that MOTS-c treatment was associated with improved blood perfusion, enhanced angiogenesis, and better collagen remodeling in ischemic flaps. Mechanistically, the study found that MOTS-c appeared to suppress phosphorylation of PLA2G4A (cytosolic phospholipase A2) via the MAPK1/ERK2–MAPK3/ERK1–NF-κB signaling cascade, thereby reducing lysosomal membrane permeabilization (LMP), decreasing endothelial pyroptosis, and enhancing autophagy. AAV-mediated PLA2G4A overexpression in vivo was used to confirm this pathway. Key limitations include the absence of human clinical data and the complexity of the multi-modal experimental design, which makes it difficult to isolate individual mechanistic contributions.
Why this grade: All efficacy data for MOTS-c in ischemic flap survival derive from rat animal models and in vitro cell experiments, with no human clinical trials or human tissue intervention data reported.
Distal ischemic necrosis remains a major challenge in reconstructive surgery. Mitochondria and lysosomes interact via signaling and membrane contacts to maintain cellular homeostasis. Mitochondrial-derived peptide MOTS-c, encoded by the MT-RNR1/12S rRNA open reading frame, enhances mitochondrial function by reducing reactive oxygen species (ROS) and stabilizing the membrane potential, potentially preserving lysosomal integrity and reducing lysosomal membrane permeabilization (LMP). This study investigated the protective effects and underlying mechanisms of MOTS-c in ischemic flaps. RNA sequencing explored MOTS-c mechanisms in ischemic flaps. Tissue clearing, laser speckle contrast imaging and Doppler analyses revealed improved blood flow perfusion following MOTS-c treatment. Histological staining (HE, Masson, F-CHP) demonstrated enhanced angiogenesis and collagen remodeling. Western blotting, ELISA, and immunofluorescence were used to assess pyroptosis, macroautophagy/autophagy, LMP, and MAPK1/ERK2-MAPK3/ERK1-NFKB/NF-κB pathway-related proteins. MOTS-c reduced endothelial pyroptosis, enhanced autophagy, and attenuated LMP in ischemic flaps. Mechanistically, in vivo overexpression of PLA2G4A/cPLA2 (phospholipase A2, group IVA (calcium, calcium dependent)) via AAV confirmed that MOTS-c enhances autophagy and reduces pyroptosis and LMP by suppressing PLA2G4A phosphorylation. Furthermore, MOTS-c inhibited PLA2G4A via the MAPK1-MAPK3-NFKB signaling cascade, thereby reducing LMP and enhancing flap survival. These findings suggest that MOTS-c restores cellular homeostasis by targeting the PLA2G4A-LMP axis, representing a promising therapeutic strategy for improving outcomes in ischemic flap surgery. Abbreviations: AA = arachidonic acid, AAV = adeno-associated virus, ACTA2/α-SMA = actin alpha 2, smooth muscle, aorta, ALs = autolysosomes, BECN1 = beclin 1, CASP1 = caspase 1, CQ = chloroquine, CTSB = cathepsin B, CTSD = cathepsin D, CTSL = cathepsin L, Co-IP = co-immunoprecipitation, DEGs = differentially expressed genes, ELISA = enzyme-linked immunosorbent assay, F-CHP = 5-FAM-conjugated collagen hybridizing peptide staining, GSDMD = gasdermin D, GO = gene Ontology, GPT/ALT = glutamic pyruvic transaminase, soluble, GOT1/AST = glutamic-oxaloacetic transaminase 1, soluble, HE = hematoxylin-eosin, HUVECs = human umbilical vein endothelial cells, IP/MS = immunoprecipitation coupled with mass spectrometry, IL1B/IL-1β = interleukin 1 beta, IL18 = interleukin 18, IP = intraperitoneal injection, IV = intravenous injection, LDBF = laser Doppler blood flow, LMP = lysosomal membrane permeability, MAP1LC3/LC3 = microtubule-associated protein 1 light chain 3, MAPK = mitogen-activated protein kinase, NAGLU = alpha-N-acetylglucosaminidase (Sanfilippo disease IIIB), NFKB/NF-κB = nuclear factor kappa B, NLRP1 = NLR family pyrin domain containing 1, NLRP3 = NLR family pyrin domain containing 3, PECAM1/CD31 = platelet/endothelial cell adhesion molecule 1, PLA2G4A/cPLA2 = phospholipase A2, group IVA (cytosolic, calcium-dependent), PYCARD/ASC = PYD and CARD domain containing, PIK3C3/VPS34 = phosphatidylinositol 3-kinase catalytic subunit type 3, PMA = phorbol 12-myristate 13-acetate, ROS = reactive oxygen speciesSQSTM1/p62 = sequestosome 1, SPR = surface plasmon resonance, scRNA-seq = single-cell RNA sequencing, UMAP = uniform manifold approximation and projection, WB = western blotting.
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