In-situ gelation of fibrin gel encapsulating platelet-rich plasma-derived exosomes promotes rotator cuff healing.

Although platelet-rich plasma-derived exosomes (PRP-Exos) hold significant repair potential, their efficacy in treating rotator cuff tear (RCT) remains unknown. In light of the potential for clinical translation of fibrin gel and PRP-Exos, we evaluated their combined impact on RCT healing and explored suitable gel implantation techniques. In vitro experiments demonstrated that PRP-Exos effectively enhanced key phenotypes changes in tendon stem/progenitor cells. Multi-modality imaging, including conventional ultrasound, shear wave elastography ultrasound, and micro-computed tomography, and histopathological assessments were performed to collectively evaluate the regenerative effects on RCT. The regenerated tendons exhibited a well-ordered structure, while bone and cartilage regeneration were significantly improved. PRP-Exos participated in the healing process of RCT. In-situ gelation of fibrin gel-encapsulated PRP-Exos at the bone-tendon interface during surgery proved to be a feasible gel implantation method that benefits the healing outcome. Comprehensive multi-modality postoperative evaluations were necessary, providing a reliable foundation for post-injury repair.

Platelet-rich plasma-derived exosomes boost mesenchymal stem cells to promote peripheral nerve regeneration.

Peripheral nerve injury (PNI) remains a severe clinical problem with debilitating consequences. Mesenchymal stem cell (MSC)-based therapy is promising, but the problems of poor engraftment and insufficient neurotrophic effects need to be overcome. Herein, we isolated platelet-rich plasma-derived exosomes (PRP-Exos), which contain abundant bioactive molecules, and investigated their potential to increase the regenerative capacity of MSCs. We observed that PRP-Exos significantly increased MSC proliferation, viability, and mobility, decreased MSC apoptosis under stress, maintained MSC stemness, and attenuated MSC senescence. In vivo, PRP-Exo-treated MSCs (pExo-MSCs) exhibited an increased retention rate and heightened therapeutic efficacy, as indicated by increased axonal regeneration, remyelination, and recovery of neurological function in a PNI model. In vitro, pExo-MSCs coculture promoted Schwann cell proliferation and dorsal root ganglion axon growth. Moreover, the increased neurotrophic behaviour of pExo-MSCs was mediated by trophic factors, particularly glia-derived neurotrophic factor (GDNF), and PRP-Exos activated the PI3K/Akt signalling pathway in MSCs, leading to the observed phenotypes. These findings demonstrate that PRP-Exos may be novel agents for increasing the ability of MSCs to promote neural repair and regeneration in patients with PNI.

Platelet-rich plasma-derived exosomes enhance mesenchymal stem cell paracrine function and nerve regeneration potential.

BACKGROUND: Peripheral nerve injury (PNI) presents a significant clinical challenge, leading to enduring sensory-motor impairments. While mesenchymal stem cell (MSC)-based therapy holds promise for PNI treatment, enhancing its neurotrophic effects remains crucial. Platelet-rich plasma-derived exosomes (PRP-Exo), rich in bioactive molecules for intercellular communication, offer potential for modulating cellular biological activity. METHODS: PRP-Exo was isolated, and its impact on MSC viability was evaluated. The effects of PRP-Exo-treated MSCs (MSCPExo) on Schwann cells (SCs) from injured sciatic nerves and human umbilical vein endothelial cells (HUVECs) were assessed. Furthermore, the conditioned medium from MSCPExo (MSCPExo-CM) was analyzed using a cytokine array and validated through ELISA and Western blot. RESULTS: PRP-Exo enhanced MSC viability. Coculturing MSCPExo with SCs ameliorated apoptosis and promoted SC proliferation following PNI. Similarly, MSCPExo-CM exhibited pro-proliferative, migratory, and angiogenic effects. Cytokine array analysis identified 440 proteins in the MSCPExo secretome, with 155 showing upregulation and 6 showing downregulation, many demonstrating potent pro-regenerative properties. ELISA confirmed the enrichment of several angiotrophic and neurotrophic factors. Additionally, Western blot analysis revealed the activation of the PI3K/Akt signaling pathway in MSCPExo. CONCLUSION: Preconditioning MSCs with PRP-Exo enhanced the paracrine function, particularly augmenting neurotrophic and pro-angiogenic secretions, demonstrating an improved potential for neural repair.

sRNA23, a novel small RNA, regulates to the pathogenesis of Streptococcus suis serotype 2.

Streptococcus suis serotype 2 (S. suis 2) is an important ubiquitous zoonotic pathogen. To date, regulatory factors and their implication in S. suis pathogenesis are not fully understood. Small non-coding RNAs (sRNAs) have been proven to function as important regulatory factors in bacterial pathogenesis and stress adaptation. Here, we identified a differentially downregulated S. suis 05ZYH33 sRNA after iron starvation by RNA-seq, which we named sRNA23. The presence of sRNA23 was further confirmed by RACE and Northern blot. Expression of sRNA23 was significantly altered under different environmental stresses such as nutritional starvation, osmotic pressure, oxidative stress, and lysozymal exposure. A sRNA23-deleted mutant exhibited relatively shorter streptococcal chains and weakened biofilm-forming ability. The mutation also resulted in decreased adherence of the S. suis 05ZYH33 to human laryngeal epidermoid carcinoma (HEp-2) cells, increased sensitivity to phagocytosis by RAW264.7 macrophages, and significantly reduced hemolytic activity. Furthermore, we observed that a sRNA23-deleted mutant had a low survival rate in pig whole blood and attenuated virulence in a mouse model. Moreover, based on RNA pull-down and electrophoretic mobility shift assay, we found that sRNA23 can directly bind to two proteins involved in adhesion and biofilm formation, namely, moonlighting protein FBA (fructose diphosphate aldolase) and rplB (50S ribosomal protein L2), respectively. Collectively, sRNA23 enhances S. suis 2 pathogenicity and the binding between sRNA23 and FBA/rplB might play an essential role in the adherence and biofilm-forming ability of S. suis 2.

MiR-190a potentially ameliorates postoperative cognitive dysfunction by regulating Tiam1.

BACKGROUND: Postoperative cognitive dysfunction (POCD) affects a large number of post-surgery patients, especially for the elderly. However, the etiology of this neurocognitive disorder is largely unknown. Even if several studies have reported a small number of miRNAs as the essential modulatory factors in POCD, these findings are still rather limited. The aim of current study was to screen the POCD-related miRNAs in the hippocampus tissues and investigate the target genes of differentially expressed miRNAs and their biological functions underlying POCD pathophysiology. METHODS: The miRNA microarray was used to find the abnormal expression of miRNAs in the hippocampus tissues from the POCD model mice to normal mice (Discovery cohort, 3 vs 3). The nominal significant results were validated in an independent sample of hippocampus tissues of 10 mice based on same miRNA microarray (Replication cohort, 5 vs 5). Expression level of the most significantly abnormal miRNA was further validated by real-time quantitative polymerase chain reaction (PCR). To determine the expression pattern among miRNAs and genes and detect the interactions, we conducted a weighted gene co-expression network analysis (WGCNA) in the miRNAs and genes expression data from hippocampus tissue of wild type mice (n = 24). The target genes of miRNAs were predicted using the miRWalk3.0 software. Furthermore, we used the ClueGO software to decipher the pathways network and reveal the biological functions of target genes of miRNAs. RESULTS: We found that nine miRNAs showed significant associations with POCD in both datasets. Among these miRNAs, mmu-miR-190a-3p was the most significant one. By performing WGCNA analysis, we found 25 co-expression modules, of which mmu-miR-190a-3p was significantly anti-correlated with red module. Moreover, in the red module, 314 genes were significantly enriched in four pathways such as axon guidance and calcium signaling pathway, which are well-documented to be associated with psychiatric disorders and brain development. Also, 169 of the 314 genes were highly correlated with mmu-miR-190a-3p, and four genes (Sphkap, Arhgef25, Tiam1, and Ntrk3) had putative binding sites at 3'-UTR of mmu-miR-190a-3p. Based on protein-protein network analysis, we detected that Tiam1 was a central gene regulated by the mmu-miR-190a-3p. CONCLUSIONS: Taken together, we conclude that mmu-miR-190a-3p is involved in the etiology of POCD and may serve as a novel predictive indicator for POCD.

Overexpression of phosphodiesterase-4 subtypes involved in surgery-induced neuroinflammation and cognitive dysfunction in mice.

Postoperative cognitive dysfunction (POCD) is characterized by cognitive impairments in patients after surgery. Hippocampal neuroinflammation induced by surgery is highly associated with POCD. Phosphodiesterase-4 (PDE4) is an enzyme that specifically hydrolyses cyclic adenosine monophosphate (cAMP), which plays an important role during neuroinflammation and the process of learning and memory. However, the role of PDE4 in the development of POCD remains unclear. Male 14-month-old C57BL/6 mice received carotid artery exposure to mimic POCD. First, we evaluated cognitive performance by a Morris water maze (MWM) and fear conditioning system (FCS) test after surgery. The expression of PDE4 subtypes, pro-inflammatory cytokines, p-CREB and PSD95 as well as cAMP levels were investigated. Then, we used rolipram, a PDE4 inhibitor, to block the effects of PDE4. The cognitive performance of the mice and the expression of PDE4 subtypes, pro-inflammatory cytokines, p-CREB and PSD95 as well as cAMP levels were examined again. Mice displayed learning and memory impairment, overexpression of PDE4B and PDE4D, elevation of pro-inflammatory cytokines, and reduction in the expression of p-CREB, PSD95 and cAMP levels after surgery. The expression of PDE4B and PDE4D in the hippocampus decreased following blocking of PDE4 by rolipram. Meanwhile, rolipram attenuated the cognitive impairment and the elevation of pro-inflammatory cytokines induced by surgery. Moreover, rolipram reversed the reduction of p-CREB and PSD95. These results indicate that PDE4 subtype overexpression may be involved in the development of surgery-induced cognitive dysfunction in mice.

Elastic, conductive, polymeric hydrogels and sponges.

As a result of inherent rigidity of the conjugated macromolecular chains resulted from the delocalized π-electron system along the polymer backbone, it has been a huge challenge to make conducting polymer hydrogels elastic by far. Herein elastic and conductive polypyrrole hydrogels with only conducting polymer as the continuous phase have been simply synthesized in the indispensable conditions of 1) mixed solvent, 2) deficient oxidant, and 3) monthly secondary growth. The elastic mechanism and oxidative polymerization mechanism on the resulting PPy hydrogels have been discussed. The resulting hydrogels show some novel properties, e.g., shape memory elasticity, fast functionalization with various guest objects, and fast removal of organic infectants from aqueous solutions, all of which cannot be observed from traditional non-elastic conducting polymer counterparts. What's more, light-weight, elastic, and conductive organic sponges with excellent stress-sensing behavior have been successfully achieved via using the resulting polypyrrole hydrogels as precursors.

Homoleptic "star" Ru(II) polypyridyl complexes: shielded chromophores to study charge-transfer at the sensitizer-TiO2 interface.

Three homoleptic star-shaped ruthenium polypyridyl complexes, termed Star YZ1, Star YZ2, and Star YZ3, where the Ru(II) center is coordinated to three bipyridine ligands each carrying two oligo(phenylene ethynylene) (OPE) rigid linker units terminating with isophthalic ester (Ipa) groups for binding to metal-oxide surfaces were synthesized. In Star YZ3, each OPE linker was substituted with two n-butoxy (n-BuO) solubilizing groups. Star complex YZ4, which is homoleptic but lacks the octahedral symmetry, was synthesized as a reference compound. The Star complexes were synthesized using two approaches: in the first, Ru(4,4'-(Br)2-2,2'-bpy)3 was reacted in a Sonogashira cross coupling reaction with the ethynyl-OPE-Ipa linkers; in the second, the 2,2'-bpy-OPE-Ipa ligands were reacted with Ru(DMSO)4(PF6)2. The photophysical behavior of the Star complexes were studied in fluid solution and anchored to the surface of mesoporous nanocrystalline TiO2 thin films (Star/TiO2). To a first approximation the excited state behavior in CH3CN was unchanged when the compounds were anchored to a TiO2 thin film, indicating that the highly symmetrical (octahedral) and rigid molecular structure of the ligands shielded the chromophoric core from the TiO2 semiconductor. Inefficient excited state injection, φ(inj) < 0.05, was observed to occur on a nanosecond time scale with slow recombination. In addition, the presence of n-BuO groups on the linker unit gave a large increase in the extinction coefficient of YZ3, which allows for enhanced harvesting of sunlight. The results indicate that molecular design on the nanometer length scale can be utilized to control excited state relaxation pathways at semiconductor surfaces.

Slow excited state injection and charge recombination at star-shaped ruthenium polypyridyl compounds--TiO2 interfaces.

The excited states of two star-shaped nanometre-sized ruthenium polypyridyl compounds were largely unchanged when anchored to nanocrystalline TiO(2) thin films due to a highly symmetrical and rigid ligand structure that isolated the chromophoric core from the semiconductor. Interfacial electron transfer occurred on unusually slow time scales.