Choosing Lunch: The Role of Selective Autophagy Adaptor Proteins

Autophagy (macroautophagy) is a lysosome-dependent catabolic pathway that degrades damaged organelles, protein aggregates, microorganisms, and other cytoplasmic components. Autophagy was previously considered to be nonselective; however, studies have increasingly established that autophagy-mediated degradation is highly regulated. Selective autophagy regulates plenty of specific cellular components through specialized molecules termed autophagy receptors, which include p62, NBR1, NDP52, optineurin, and VCP among others. Autophagy receptors recognize ubiquitinated cargo and interact with the LC3/GABARAP/Gate16 protein on the membrane of nascent phagophore. In this review, we summarize the advances in the molecular mechanisms of selective autophagy adaptor proteins

Novel PVA–Hyaluronan–Siloxane Hybrid Nanofiber Mats for Bone Tissue Engineering

Hyaluronan (HA) is a natural biodegradable biopolymer; its biological functions include cell adhesion, cell proliferation, and differentiation as well as decreasing inflammation, angiogenesis, and regeneration of damaged tissue. This makes it a suitable candidate for fabricating nanomaterials with potential use in tissue engineering. However, HA nanofiber production is restricted due to the high viscosity, low evaporation rate, and high surface tension of HA solutions. Here, hybrids in the form of continuous and randomly aligned polyvinyl alcohol (PVA)–(HA)–siloxane nanofibers were obtained using an electrospinning process. PVA–HA fibers were crosslinked by a 3D siloxane organic–inorganic matrix via sol-gel that restricts natural hydrophilicity and stiffens the structure. The hybrid nanofiber mats were characterized by FT-IR, micro-Raman spectroscopy, SEM, and biological properties. The PVA/HA ratio influenced the morphology of the hybrid nanofibers. Nanofibers with high PVA content (10PVA-8 and 10PVA-10) form mats with few beaded nanofibers, while those with high HA content (5PVA-8 and 5PVA-10) exhibit mats with mound patterns formed by “ribbon-like” nanofibers. The hybrid nanofibers were used as mats to support osteoblast growth, and they showed outstanding biological properties supporting cell adhesion, cell proliferation, and cell differentiation. Importantly, the 5PVA-8 mats show 3D spherical osteoblast morphology; this suggests the formation of tissue growth. These novel HA-based nanomaterials represent a relevant advance in designing nanofibers with unique properties for potential tissue regeneration