Ebara, M. | bioRxiv Science

bioRxiv2026

Immunomodulatory mechanisms of submicron phosphatidylserine-exposing polymeric particles (PSPs)

Macrophages are highly dynamic cells that maintain tissue homeostasis by regulating both initiation and resolution of inflammation. During efferocytosis, macrophages recognize the eat me signal, phosphatidylserine (PS), exposed at the surface of apoptotic cells, leading to the resolution of inflammation and acquisition of a pro-resolving phenotype. Inspired by this endogenous mechanism, PS-based biomaterials have demonstrated immunomodulatory potential. However, the molecular mechanisms underlying PS-mediated macrophage reprogramming remain poorly understood. Here, submicron PS-exposing polymeric particles (PSPs; [~]300 nm) were developed to improve the suitability of PSP formulations for future systemic administration while preserving their immunomodulatory activity. PSPs were efficiently internalized by macrophages through both actin- and dynamin-dependent pathways. PSP treatment significantly reduced IL-6 and IL-12p70 production in LPS-stimulated macrophages, whereas induction of the classical anti-inflammatory M2 marker CD206 was limited. Transcriptomic analysis revealed coordinated attenuation of inflammatory signaling pathways, including downregulation of Myd88, Nfkb1, Rel, and Irf8, together with activation of NRF2-associated antioxidant pathways characterized by increased expression of Nfe2l2, Hmox1, Prdx1, Gclm, and Gclc. Activation of antioxidant-associated genes together with reduced Irf8 expression suggests that PSP promotes inflammatory resolution through coordinated redox adaptation and selective attenuation of inflammatory signaling. Collectively, these findings provide mechanistic insight into PS-mediated macrophage reprogramming and support the future development of systemically administered therapies for chronic inflammatory diseases, including vascular inflammatory disorders. HighlightsO_LISubmicron PSPs retain immunomodulatory activity of apoptotic cell-mimicking biomaterials. C_LIO_LIPSPs are rapidly internalized through actin- and dynamin-dependent pathways. C_LIO_LIPSPs attenuate inflammatory signaling and selectively suppress IL-6 and IL-12p70 production. C_LIO_LIPSPs induce NRF2-associated antioxidant and glutathione responses. C_LIO_LITranscriptomics reveals an early redox-adaptive macrophage program. C_LI

bioengineering↗

bioRxiv2024

A Novel Gene Synthesis Platform for Designing Functional Protein Polymers

Recombinant protein polymers with repeat sequences of specific amino acids can be regarded as sustainable functional materials that can be designed using genetic engineering. However, synthesizing genes encoding these proteins is significantly time-consuming and labor-intensive owing to the difficulty of using common gene synthesis tools, such as restriction enzymes and PCR primers. To overcome these obstacles, we propose a novel method: seamless cloning of rolling-circle amplicons (SCRCA). This method involves one-pot preparation of repetitive-sequence genes with overlapping ends for cloning, facilitating the easy construction of the desired recombinants. Using SCRCA, we synthesized 10 genes encoding hydrophilic resilin-like and hydrophobic elastin-like repeat units that induce liquid-liquid phase separation. SCRCA shows higher transformation efficiency and better workability than conventional methods, and the time and budget required for SCRCA are comparable to those required for non-repetitive-sequence gene synthesis. Additionally, SCRCA allows the construction of a repeat unit library at a low cost. The library shows considerably higher diversity compared with that of the state-of-the-art method. By combining this library construction with the directed evolution concept, we can rapidly develop an elastin-like protein polymer with a desired function. SCRCA can greatly accelerate research on protein polymers.

bioengineering↗