MOTS-c, a mitochondrial-derived peptide, ameliorates lysosomal membrane permeability and improves survival of soft tissue transplantation

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.