Matrix regeneration proteins in the hypoxia-triggered exosomes of shoulder tenocytes and adipose-derived mesenchymal stem cells

Abstract

Regenerative functions of exosomes rely on their contents which are influenced by pathological stimuli, including hypoxia, in rotator cuff tendon injuries (RCTI). The hypoxic environment triggers tenocytes and adjacent adipose-derived mesenchymal stem cells (ADMSCs) to release regenerative mediators to the ECM via the exosomes which elicit autocrine/paracrine responses to protect the tendon matrix from injury. We investigated the exosomal protein contents from tenocytes and subcutaneous ADMSCs from the shoulder of Yucatan microswine cultured under hypoxic conditions (2% O 2 ). The exosomal proteins were detected using high-resolution massspectrometry nano-LC-MS/MS Tribrid system and were compiled using 'Scaffold' software. Hypoxic exosomes from tenocytes and ADMSCs carried 199 and 65 proteins, respectively. The key proteins identified by mass spectrometry and associated with ECM homeostasis from hypoxic ADMSCs included MMP2, COL6A, CTSD and TN-C and those from hypoxic tenocytes were THSB1, NSEP1, ITIH4 and TN-C. These findings were confirmed at the mRNA and protein level in the hypoxic ADMSCs and tenocytes. These proteins are involved in multiple signaling pathways of ECM repair/regeneration. This warrants further investigations for their translational significance in the management of RCTI.

Proteomics identifies differences in fibrotic potential of extracellular vesicles from human tendon and muscle fibroblasts

“…Functional analysis of the TenX proteome identified an enrichment of ECM proteins (collagens), translational proteins (ribosomal proteins) and cytoskeletal proteins (keratins and myosins), which is consistent with the proteome of porcine tendon exosomes [ 18 ]. On the other hand FibX distinctly lacked a high abundance of ribosomal proteins, Golgi transport proteins and ATPase ion-transporters but contained significantly higher levels of the collagenase MMP2 than TenX.…”

“…No one has to our knowledge previously performed EV proteomics on human tendon tissue. The only other tendon fibroblast EV proteome data published is of porcine tendon exosomes, where only 199 proteins were identified [ 18 ], making the current TenX proteome profile the most comprehensive to date. MyoX contained significantly more of some of EV marker proteins, which was expected as Hsc70 and Hsp90-β upregulation are required during myoblast differentiation [ 38 – 40 ], and the presence of these chaperones might be a mechanism of autocrine or paracrine signalling.…”

“…plasma [ 14 ], adipose stem cells [ 15 ], tendon progenitors [ 16 ], macrophages [ 17 ], have demonstrated that signalling through EVs can modulate the expression of genes that regulate ECM synthesis and remodelling. Exosomes derived from tendon cells have also been reported [ 18 , 19 ]; and one study showed that tendon cell-derived exosomes induce the expression of tenogenic genes in bone marrow-derived mesenchymal stem cells in a TGFβ-dependent manner [ 19 ]. Compared to tendon, muscle is a more complex tissue with more than one cell type.…”

Toxicoproteomic Profiling of hPXR Transgenic Mice Treated with Rifampicin and Isoniazid

“…ANXA5 also increased in mPxr −/− mice treated with both rifampicin and isoniazid (1.22-relative change). The up-regulation of these proteins suggests that tissue injury was induced by the antitubercular drugs [ 50 , 51 , 52 ].…”

Hybrid interpenetrating hydrogel network favoring the bidirectional migration of tenocytes for rotator cuff tendon regeneration

“…The isolated tenocytes were maintained in DMEM containing 20% FBS and antibiotics at 37°C and 5% CO 2 in a humidified incubator, the media was changed twice a week, passaged at 70–80% confluency, and the cells in passage 2–4 were used for the studies. The cells cultured in chamber slides were characterized based on the immuno‐positivity of tendon specific biomarkers such as tenomodulin and scleraxis 17 . Collagen‐1‐coated (Zen‐Bio) culture wares were used for tenocyte isolation and maintenance.…”