Limited impact of fibromodulin deficiency on the development of experimental skin fibrosis

ASPORIN: A root of the matter in tumors and their host environment

Asporin (ASPN) has been identified as one of the members of the class I small leucine-rich proteoglycans (SLRPs) family in the extracellular matrix (ECM). It is involved in classic ensigns of cancers such as self-dependent growth, resistance to growth inhibitors, restricting apoptosis, cancer metastasis, and bone-related disorders. ASPN is different from other members of SLRPs, such as decorin (DCN) and biglycan (BGN), in a way that it contains a distinctive length of aspartate (D) residues in the amino (N) -terminal region. These D-repeats residues possess germline polymorphisms and are identified to be linked with cancer progression and osteoarthritis (OA). The polyaspartate stretch in the N-terminal region of the protein and its resemblance to DCN are the reasons it is called asporin. In this review, we comprehensively summarized and updated the dual role of ASPN in various malignancies, its structure in mice and humans, variants, mutations, cancer-associated signalings and functions, the relationship between ASPN and cancer-epithelial, stromal fibroblast crosstalk, immune cells and immunosuppression in cancer and other diseases. In cancer and other bone-related diseases, ASPN is identified to be regulating various signaling pathways such as TGFβ, Wnt/β-catenin, notch, hedgehog, EGFR, HER2, and CD44-mediated Rac1. These pathways promote cancer cell invasion, proliferation, and migration by mediating the epithelial-to-mesenchymal transition (EMT) process. Finally, we discussed mouse models mimicking ASPN in vivo function in cancers and the probability of therapeutic targeting of ASPN in cancer cells, fibrosis, and other bone-related diseases.

Bioreactors for Vocal Fold Tissue Engineering

It is estimated that almost one-third of the United States population will be affected by a vocal fold (VF) disorder during their lifespan. Promising therapies to treat VF injury and scarring are mostly centered on VF tissue engineering strategies such as the injection of engineered biomaterials and cell therapy. VF tissue engineering, however, is a challenging field as the biomechanical properties, structure, and composition of the VF tissue change upon exposure to mechanical stimulation. As a result, the development of long-term VF treatment strategies relies on the characterization of engineered tissues under a controlled mechanical environment. In this review, we highlight the importance of bioreactors as a powerful tool for VF tissue engineering with a focus on the current state of the art of bioreactors designed to mimic phonation in vitro. We discuss the influence of the phonatory environment on the development, function, injury, and healing of the VF tissue and its importance for the development of efficient therapeutic strategies. A concise and comprehensive overview of bioreactor designs, principles, operating parameters, and scalability are presented. An in-depth analysis of VF bioreactor data to date reveals that mechanical stimulation significantly influences cell viability and the expression of proinflammatory and profibrotic genes in vitro. Although the precision and accuracy of bioreactors contribute to generating reliable results, diverse gene expression profiles across the literature suggest that future efforts should focus on the standardization of bioreactor parameters to enable direct comparisons between studies. Impact statement We present a comprehensive review of bioreactors for vocal fold (VF) tissue engineering with a focus on the influence of the phonatory environment on the development, function, injury, and healing of the VFs and the importance of mimicking phonation on engineered VF tissues in vitro. Furthermore, we put forward a strong argument for the continued development of bioreactors in this area with an emphasis on the standardization of bioreactor designs, principles, operating parameters, and oscillatory regimes to enable comparisons between studies.

Dendritic cells maintain dermal adipose-derived stromal cells in skin fibrosis

Scleroderma is a group of skin-fibrosing diseases for which there are no effective treatments. A feature of the skin fibrosis typical of scleroderma is atrophy of the dermal white adipose tissue (DWAT). Adipose tissue contains adipose-derived mesenchymal stromal cells (ADSCs) that have regenerative and reparative functions; however, whether DWAT atrophy in fibrosis is accompanied by ADSC loss is poorly understood, as are the mechanisms that might maintain ADSC survival in fibrotic skin. Here, we have shown that DWAT ADSC numbers were reduced, likely because of cell death, in 2 murine models of scleroderma skin fibrosis. The remaining ADSCs showed a partial dependence on dendritic cells (DCs) for survival. Lymphotoxin β (LTβ) expression in DCs maintained ADSC survival in fibrotic skin by activating an LTβ receptor/β1 integrin (LTβR/β1 integrin) pathway on ADSCs. Stimulation of LTβR augmented the engraftment of therapeutically injected ADSCs, which was associated with reductions in skin fibrosis and improved skin function. These findings provide insight into the effects of skin fibrosis on DWAT ADSCs, identify a DC-ADSC survival axis in fibrotic skin, and suggest an approach for improving mesenchymal stromal cell therapy in scleroderma and other diseases.