Vimentin at the core of wound healing

As a member of the large family of intermediate filaments (IFs), vimentin has emerged as a highly dynamic and versatile cytoskeletal protein involved in many key processes of wound healing. It is well established that vimentin is involved in epithelial-mesenchymal transition (EMT) during wound healing and metastasis, during which epithelial cells acquire more dynamic and motile characteristics. Moreover, vimentin participates in multiple cellular activities supporting growth, proliferation, migration, cell survival, and stress resilience. Here, we explore the role of vimentin at each phase of wound healing, with focus on how it integrates different signaling pathways and protects cells in the fluctuating and challenging environments that characterize a healing tissue.

Vimentin takes a hike - Emerging roles of extracellular vimentin in cancer and wound healing

Vimentin is a cytoskeletal protein important for many cellular processes, including proliferation, migration, invasion, stress resistance, signaling, and many more. The vimentin-deficient mouse has revealed many of these functions as it has numerous severe phenotypes, many of which are found only following a suitable challenge or stress. While these functions are usually related to vimentin as a major intracellular protein, vimentin is also emerging as an extracellular protein, exposed at the cell surface in an oligomeric form or secreted to the extracellular environment in soluble and vesicle-bound forms. Thus, this review explores the roles of the extracellular pool of vimentin (eVIM), identified in both normal and pathological states. It focuses specifically on the recent advances regarding the role of eVIM in wound healing and cancer. Finally, it discusses new technologies and future perspectives for the clinical application of eVIM.

The molecular biophysics of extracellular vimentin and its role in pathogen-host interactions

Vimentin, an intermediate filament protein typically located in the cytoplasm of mesenchymal cells, can also be secreted as an extracellular protein. The organization of extracellular vimentin strongly determines its functions in physiological and pathological conditions, making it a promising target for future therapeutic interventions. The extracellular form of vimentin has been found to play a role in the interaction between host cells and pathogens. In this review, we first discuss the molecular biophysics of extracellular vimentin, including its structure, secretion, and adhesion properties. We then provide a general overview of the role of extracellular vimentin in mediating pathogen-host interactions, with a focus on its interactions with viruses and bacteria. We also discuss the implications of these findings for the development of new therapeutic strategies for combating infectious diseases.

Cytoskeletal vimentin regulates cell size and autophagy through mTORC1 signaling

The nutrient-activated mTORC1 (mechanistic target of rapamycin kinase complex 1) signaling pathway determines cell size by controlling mRNA translation, ribosome biogenesis, protein synthesis, and autophagy. Here, we show that vimentin, a cytoskeletal intermediate filament protein that we have known to be important for wound healing and cancer progression, determines cell size through mTORC1 signaling, an effect that is also manifested at the organism level in mice. This vimentin-mediated regulation is manifested at all levels of mTOR downstream target activation and protein synthesis. We found that vimentin maintains normal cell size by supporting mTORC1 translocation and activation by regulating the activity of amino acid sensing Rag GTPase. We also show that vimentin inhibits the autophagic flux in the absence of growth factors and/or critical nutrients, demonstrating growth factor-independent inhibition of autophagy at the level of mTORC1. Our findings establish that vimentin couples cell size and autophagy through modulating Rag GTPase activity of the mTORC1 signaling pathway.

Exosomal vimentin from adipocyte progenitors accelerates wound healing

Adipose stem cell-derived exosomes have great potential in accelerating cutaneous wound healing by optimizing fibroblast activities. Recent studies have demonstrated that exosomes play an active role in the transport of functional cytoskeletal proteins such as vimentin. Previously we showed that vimentin serves as a coordinator of the healing process. Therefore, we hypothesized that vimentin incorporated into the exosomes may contribute to mediate fibroblast activities in wound healing. Our results revealed that exosomal vimentin from adipocyte progenitor cells acts as a promoter of fibroblast proliferation, migration, and ECM secretion. Furthermore, our in vitro and in vivo experiments provide evidence that exosomal vimentin shortens the healing time and reduces scar formation. These findings suggest the reciprocal roles of exosomes and vimentin in accelerating wound healing. Exosomes can serve as an efficient transportation system to deliver and internalize vimentin into target cells, while vimentin could have an impact on exosome transportation, internalization, and cell communication.