Novel Biodegradable Polymeric Microparticles Facilitate Scarless Wound Healing by Promoting Re-epithelialization and Inhibiting Fibrosis

Abstract

Despite decades of research, the goal of achieving scarless wound healing remains elusive. One of the approaches, treatment with polymeric microcarriers, was shown to promote tissue regeneration in various in vitro models of wound healing. The in vivo effects of such an approach are attributed to transferred cells with polymeric microparticles functioning merely as inert scaffolds. We aimed to establish a bioactive biopolymer carrier that would promote would healing and inhibit scar formation in the murine model of deep skin wounds. Here we characterize two candidate types of microparticles based on fibroin/gelatin or spidroin and show that both types increase re-epithelialization rate and inhibit scar formation during skin wound healing. Interestingly, the effects of these microparticles on inflammatory gene expression and cytokine production by macrophages, fibroblasts, and keratinocytes are distinct. Both types of microparticles, as well as their soluble derivatives, fibroin and spidroin, significantly reduced the expression of profibrotic factors Fgf2 and Ctgf in mouse embryonic fibroblasts. However, only fibroin/gelatin microparticles induced transient inflammatory gene expression and cytokine production leading to an influx of inflammatory Ly6C+ myeloid cells to the injection site. The ability of microparticle carriers of equal proregenerative potential to induce inflammatory response may allow their subsequent adaptation to treatment of wounds with different bioburden and fibrotic content.

Production of protein-based polymers in Pichia pastoris

“…However, whereas in the latter host 70–80% of MaSp2 was in the water-insoluble cellular fraction, in P. pastoris 60% was in the soluble fraction. The proteins are being developed into matrices for tissue engineering and drug delivery (Agapov et al, 2009; Moisenovich et al, 2016; Moisenovich et al, 2011; Nosenko et al, 2018).…”

Overcoming the Inflammatory Stage of Non-Healing Wounds: In Vitro Mechanism of Action of Negatively Charged Microspheres (NCMs)

“…In fact, studies have demonstrated that macrophages in contact with several biomaterials produce lower levels of proinflammatory cytokines, such as IL-1β, CXCL8(IL-8), IL-12 and TNF-α, and higher levels of immunosuppressive cytokines, such as IL-10 [ 11 , 40 , 41 ]. Although the mechanism is not clear, NCM characteristics, such as physical properties (geometry, topography and porosity) and biochemical properties (surface chemistry, ligand functionalization and degradation mode) have been determined as critical factors in the host response to the material [ 42 ].…”

Effects of Recombinant Spidroin rS1/9 on Brain Neural Progenitors After Photothrombosis-Induced Ischemia

“…Microparticles based on recombinant spidroin rS1/9 with sizes of 100 and 300 μm were obtained as described in Nosenko et al (2018) . Microparticles were stored in 70% ethanol and washed five times in PBS prior to use.…”

“…Using the protocols described earlier regenerated fibroin was obtained and later lyophilized (Nosenko et al, 2018). Recombinant protein rS1/9 produced by yeast cells carrying gene rS1/9 was isolated from lysed cells, purified by ion-exchange chromatography in fast protein liquid chromatography up to 95% purity and lyophilized.…”