[Preparation and Performance of a Novel Polyurethane Microporous Film on Polypropylene Medical Mesh Surface]. / ä¸€ç§èšæ°¨é ¯å¾®å­”è–„è†œåŒ»ç”¨è¡¥ç‰‡è¡¨å±‚ææ–™çš„åˆ¶å¤‡åŠå ¶æ€§èƒ½ç ”ç©¶.

Objective: This study aims to develop a medical patch surface material featuring a microporous polyurethane (PU) membrane and to assess the material's properties and biological performance. The goal is to enhance the clinical applicability of pelvic floor repair patch materials. Methods: PU films with a microporous surface were prepared using PU prepolymer foaming technology. The films were produced by optimizing the PU prepolymer isocyanate index (R value) and the relative humidity (RH) of the foaming environment. The surface morphology of the PU microporous films was observed by scanning electron microscopy, and the chemical properties of the PU microporous films, including hydrophilicity, were analyzed using infrared spectroscopy, Raman spectroscopy, and water contact angle measurements. In vitro evaluations included testing the effects of PU microporous film extracts on the proliferation of L929 mouse fibroblasts and observing the adhesion and morphology of these fibroblasts. Additionally, the effect of the PU microporous films on RAW264.7 mouse macrophages was studied. Immune response and tissue regeneration were assessed in vivo using Sprague Dawley (SD) rats. Results: The PU films exhibited a well-defined and uniform microporous structure when the R value of PU prepolymer=1.5 and the foaming environment RH=70%. The chemical structure of the PU microporous films was not significantly altered compared to the PU films, with a significantly lower water contact angle ([55.7±1.5]° ) compared to PU films ([69.5±1.7]° ) and polypropylene (PP) ([ 104.3±2.5]°), indicating superior hydrophilicity. The extracts from PU microporous films demonstrated good in vitro biocompatibility, promoting the proliferation of L929 mouse fibroblasts. The surface morphology of the PU microporous films facilitated fibroblast adhesion and spreading. The films also inhibited the secretion of tumor necrosis factor-α (TNF-α) and interleukin (IL)-1ß by RAW264.7 macrophages while enhancing IL-10 and IL-4 secretion. Compared to 24 hours, after 72 hours of culture, the expression levels of TNF-α and IL-1ß were reduced in both the PU film and PU microporous film groups and were significantly lower than those in the PP film group (P<0.05), with the most notable decreases observed in the PU microporous film group. IL-10 and IL-4 levels increased significantly in the PU microporous film group, surpassing those in the PP film group (P<0.01), with the most pronounced increase in IL-4. The PU microporous film induced mild inflammation with no significant fibrous capsule formation in vivo. After 60 days of implantation, the film partially degraded, showing extensive collagen fiber growth and muscle formation in its central region. Conclusion: The PU microporous film exhibits good hydrophilicity and biocompatibility. Its surface morphology enhances cell adhesion, regulates the function of RAW264.7 macrophages, and promotes tissue repair, offering new insights for the design of pelvic floor repair and reconstruction patch materials.

P2X7Rs: new therapeutic targets for osteoporosis.

Increasing evidence suggests that both the occurrence and progression of osteoporosis are associated with inflammation, especially in primary osteoporosis. The maintenance of skeletal homeostasis is dependent on the complex regulation of bone metabolism. Numerous evidence suggested that purinoceptor networks are essential for bone homeostasis. In this review, the relationship between inflammation and the development of osteoporosis and the role of P2X7 receptor (P2X7R) in regulating the dynamic regulation of bone reconstruction were covered. We also discussed how P2X7R regulates the balance between resorption and bone formation by osteoblasts and reviewed the relevance of P2X7R polymorphisms in skeletal physiology. Finally, we analyzed potential targets of P2X7R for osteoporosis.

Single-cell RNA sequencing deciphers the mechanism of sepsis-induced liver injury and the therapeutic effects of artesunate.

Liver, as an immune and detoxification organ, represents an important line of defense against bacteria and infection and a vulnerable organ that is easily injured during sepsis. Artesunate (ART) is an anti-malaria agent, that also exhibits broad pharmacological activities including anti-inflammatory, immune-regulation and liver protection. In this study, we investigated the cellular responses in liver to sepsis infection and ART hepatic-protective mechanisms against sepsis. Cecal ligation and puncture (CLP)-induced sepsis model was established in mice. The mice were administered ART (10 mg/kg, i.p.) at 4 h, and sacrificed at 12 h after the surgery. Liver samples were collected for preparing single-cell RNA transcriptome sequencing (scRNA-seq). The scRNA-seq analysis revealed that sepsis-induced a dramatic reduction of hepatic endothelial cells, especially the subtypes characterized with proliferation and differentiation. Macrophages were recruited during sepsis and released inflammatory cytokines (Tnf, Il1b, Il6), chemokines (Ccl6, Cd14), and transcription factor (Nfkb1), resulting in liver inflammatory responses. Massive apoptosis of lymphocytes and abnormal recruitment of neutrophils caused immune dysfunction. ART treatment significantly improved the survival of CLP mice within 96 h, and partially relieved or reversed the above-mentioned pathological features, mitigating the impact of sepsis on liver injury, inflammation, and dysfunction. This study provides comprehensive fundamental proof for the liver protective efficacy of ART against sepsis infection, which would potentially contribute to its clinical translation for sepsis therapy. Single cell transcriptome reveals the changes of various hepatocyte subtypes of CLP-induced liver injury and the potential pharmacological effects of artesunate on sepsis.

Low-magnitude vibration induces osteogenic differentiation of bone marrow mesenchymal stem cells via miR-378a-3p/Grb2 pathway to promote bone formation in a rat model of age-related bone loss.

The dysfunction of bone marrow mesenchymal stem cells (BMSCs) in osteogenic differentiation is one of the main causes of age-related bone loss. Our previous studies have shown that low-magnitude vibration (LMV) induces the osteogenic differentiation of BMSCs derived from ovariectomized osteoporotic rats. To investigate whether LMV promotes osteogenic differentiation of BMSCs and its underlying mechanisms in aged rats, 20-month-old female Sprague-Dawley rats (n = 20) were randomly divided into LMV group (rats were vibrated at 0.3 g and 90 Hz for 30 minutes, once daily, 5 days a week until 12 weeks for subsequent analysis, n = 10), static group (rats were placed in the box on the vibration platform without vibration, n = 10); 6-month-old female Sprague-Dawley rats were used as control (young group, n = 10). The bone mineral density and bone strength of aged rats were significantly decreased compared with the young rats. Furthermore, the primary BMSCs isolated and cultured from the aged rats with the whole-bone marrow differential pasting method showed a decreased ability in osteogenic differentiation compared with that from the young rats. Then the differentially expressed miRNAs between the aged and young rat-derived BMSCs were screened by high-throughput sequencing and verified by qRT-PCR, and we found that miR-378a-3p was significantly downregulated in the aged rat-derived BMSCs compared with the young rat-derived BMSCs. By transfecting miRNA mimics and inhibitors, miR-378a-3p was confirmed to promote the expression levels of osteogenic genes (Runx2, ALP, Col I, and OCN) and ALP activity of the aged rat-derived BMSCs. Meanwhile, the expression levels of osteogenic genes and miR-378a-3p of aged rat-derived BMSCs were significantly upregulated by LMV (cells were vibrated at 0.3 g and 90 Hz for 30 minutes a day, until 5 days for subsequent analysis), while the LMV-induced osteogenic gene expression levels of aged rat-derived BMSCs were suppressed by miR-378a-3p inhibitors. Furthermore, the inhibition of growth factor receptor-bound protein 2 (Grb2) by miR-378a-3p and Grb2-siRNA promoted the LMV-induced osteogenic differentiation of aged rat-derived BMSCs. Additionally, LMV was found to promote bone mineral density and bone strength of aged rats in vivo, as well as upregulating the expression level of miR-378a-3p and downregulating the expression level of Grb2 of BMSCs from aged rats. These results suggest that LMV induces osteogenic differentiation of BMSCs through miR-378a-3p/Grb2 pathway to improve bone mineral density and mechanical properties in a rat model of age-related bone loss.

[Low-magnitude vibration promotes osteogenesis of osteoblasts in ovariectomized osteoporotic rats via the estrogen receptor α].

The purpose of this study was to investigate the effect of low-magnitude vibration on osteogenesis of osteoblasts in ovariectomized rats with osteoporosis via estrogen receptor α(ERα). The mRNA expression of osteogenic markers were examined with qRT-PCR, based on which the optimal vibration parameter for promoting osteogenesis was determined (45 Hz × 0.9 g, g = 9.8 m/s2). Then we loaded the optimal vibration parameter on the osteoblasts of ovariectomized rats with osteoporosis. The protein expression of osteogenic markers and ERα were detected with Western blot; the distribution of ERα was examined with immunofluorescence technique. Finally, through inhibiting the expression of ERα with estrogen receptor inhibitor ICI182780, the protein and mRNA expression of osteogenic markers were examined. First, the results showed that low-magnitude vibration could promote the expression of osteogenic markers and ERα in osteoblasts of ovariectomized rats with osteoporosis (P < 0.05), and make ERα transfer to the nucleus. On the other hand, the results also showed that after inhibiting the expression of ERα in osteoblasts of ovariectomized rats with osteoporosis, the protein and mRNA expression of osteogenic marker were decreased (P < 0.05). In our study, low-magnitude vibration played an important role in the osteogenesis of osteoblasts in ovariectomized rats with osteoporosis through increasing the expression and causing translocation of ERα. Furthermore, it provides a theoretical basis for the application of low-magnitude vibration in the prevention and treatment of postmenopausal osteoporosis.

[Screening of the Optimum Medium for Rat Mesenchymal Stem Cells].

OBJECTIVE: To investigate the effect of three different cell culture mediums, DMEM-LG, α-MEM and DMEM/F12, on the growth of rat bone marrow mesenchymal stem cells (BMSCs) in vitro, and so that to screen out the most suitable medium for in vitro culturing the rat BMSCs. METHODS: BMSCS were isolated from the femur and tibia of SD rats by whole bone marrow differential adherence method. The isolated cells were then cultured with three culture mediums, DMEM-LG, α-MEM and DMEM/F12. The rat BMSCs morphology, adhesion, proliferation, the time of passage and the number the colony at day 14 in three mediums respectively were observed with inverted phase contrast microscopy and compared. Flow cytometry was used to identify and observe the effects of different mediums on the surface antigen expression of rats BMSCs. RESULTS: Compared with the other two groups of media, BMSCs cultured in DMEM-LG had shorter colony formation time, shorter first passage time, more clone formation (14±2) and showed uniform morphology and the highest attachment efficiency (47.0±2.8)%. Meanwhile, BMSCs cultured with DMEM-LG entered logarithmic growth phase after only 4 days of culturing and showed the highest average specific growth rate and the largest average number of propagations per unit time. The total number of cells reached about (2.2-2.7)×105 mL-1 within three days. The cells cultured with 3 mediums were all identified as rat BMSCs, and the expression of surface antigen in BMSCs was not significantly affected by different media. CONCLUSION: DMEM-LG is more suitable for proliferation of rat BMSCs in vitro.

Conformation-Directed Micelle-to-Vesicle Transition of Cholesterol-Decorated Polypeptide Triggered by Oxidation.

Hierarchical self-assembly of synthetic polypeptides has attracted increasing interests due to its protein-mimetic structure and great potential in nanotechnology and biomedical applications. However, controlling the morphology and function of polymeric nanostructures via secondary structures remains largely unexplored. Here, we report an unusual micelle-to-vesicle transformation of cholesterol-decorated poly(l-cysteine) copolymer assemblies in response to reactive oxygen species (ROS). We found that the interesting morphological transition correlates with the alteration in conformations from ß-sheet to α-helix, which grants an attractive "on-off" switch for triggered release and cellular interaction. We further demonstrated the usefulness of the conformation-regulated assembly strategy both in vitro and in vivo, taking cancer treatment as a model. The work offers a new insight on the folding and hierarchical assembly of polypeptides and a novel approach for the development of smart platforms in biosensing, disease treatment, and diagnostic applications.

Antibacterial and Biocompatible Cross-Linked Waterborne Polyurethanes Containing Gemini Quaternary Ammonium Salts.

A cross-linked waterborne polyurethane (CPTMGPU) with long-term stability was developed from poly(ethylene glycol) (PEG), polyoxytetramethylene glycol (PTMG), isophorone diisocyanate (IPDI), l-lysine, and its derivative diamine consisting of gemini quaternary ammonium salt (GQAS), using ethylene glycol diglycidyl ether (EGDE) as a cross-linker. Weight loss test, X-ray photoelectron spectroscopy (XPS) measurements, and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were performed to prove the surface structure and stability of these CPTMGPU films. Furthermore, the GQAS-bearing CPTMGPUs show repeatable contact-active antibacterial efficacy against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria and do not show any inhibition effect against fibroblasts in vitro. After subcutaneous implantation in rats, the CPTMGPU films manifest good biocompatibility in vivo, despite the presence of a typical foreign body reaction toward surrounding tissues and mild systematic inflammation reaction that could be eliminated after a short implantation period, as demonstrated by histology and immunohistochemistry combined with interleukin (IL)-1ß, IL-4, IL-6, IL-10, and TNF-α analysis though enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (qRT-PCR). Therefore, these cross-linked waterborne polyurethanes hold great promise for antibacterial applications in vivo.

Influence of the vaccinating density of A549 cells on tumorigenesis and distant organ metastasis in a lung cancer mice model.

Lung metastasis of malignant tumors, such as lung carcinoma, is a major cause of cancer-related deaths worldwide. The commonly used lung tumor models were established by subcutaneous or intravenous injection of the non-small cell lung cancer cell line A549 in mice. However, the influence of cell densities on tumorigenesis and distant organ metastasis remains poorly investigated. In this study, A549 cells were subcutaneously injected into mice at 1 × 107 cells/mL, 5 × 106 cells/mL, and 1 × 106 cells/mL or intravenously at 1 × 106 cells/mL, 5 × 106 cells/mL, and 1 × 106 cells/mL. Then, histology analysis, immunohistochemistry staining, and in-situ TUNEL assay were performed to evaluate tumor growth and metastasis. Results showed that subcutaneously injecting the A549 cells could develop tumors and that fewer apoptotic cells were found in the 5 × 106 cells/mL group than in the other two groups. In groups intravenously injected with A549 cells, there were tumor nodules in all groups, and the 1 × 105 cells/mL group showed longer survival time than the other two groups without any distant organ metastasis. There were tumor nodules formed in the liver in the 1 × 106 cells/mL group at 14 d. Together, our results demonstrated that 5 × 106 cells/mL and 1 × 105 cells/mL are the optimal cell concentrations for the subcutaneous and experimental metastatic models, respectively.

Adenovirus-mediated overexpression FADD induces a significant antitumor effect on human colorectal cancer cells both in vitro and in vivo.

The Wnt/ß-catenin signaling pathway plays important roles in cancers such as colorectal cancer. Colon cancer cells secrete and express high levels of ß-catenin, which may stimulate autocrine signaling and further enhance activities of the canonical Wnt signaling pathway. Free ß-catenin in the cytoplasm and nucleus leads to its association with T cell factor (TCF)/lymphocyte enhancing factor (Lef) transcription factors, and subsequent transcriptional activation of downstream target genes. FADD plays a key role in cellular apoptosis in many different types of cancer. Therefore, a recombinant adenovirus is constructed, in which an apoptosis gene FADD is placed under control of a promoter containing Tcf-responsive elements. It is observed that FADD overexpression can suppress cell growth and enhance apoptosis of SW480 cells in vitro. In addition, Ad-FADD can also suppress the growth of subcutaneous xenografts in the nude mice. Together, these results suggest that Ad-FADD has anti-proliferative and pro-apoptotic effects in colon cancer cells, which provides a novel strategy for treatment of colorectal cancer.

[Effects of MSP on Cell Cycle and EMT of Non-Small Cell Lung Cancer PC14].

OBJECTIVE: To study the effect of macrophage stimulating protein (MSP) on the cell cycle of non-small cell lung cancer PC14 cells without expression of recepteur d'originenanta (RON) and MSP,and analyse its effect on PC14's epithelial mesenchymal transition (EMT) capacity. METHODS: Vitro culture PC14 (blank control),PC14-Mst1-pEGFP-N1 (stablely expressed MSP) and PC14-pEGFP-N1. Cell cycles were detected by flow cytometry and the gaps between cells during growth were measured by transmission electron microscope (TEM); RT-PCR and Western blot were used to figure out the shifts of EMT related gene expression in PC14-Mst1-pEGFP-N1 cells. RESULTS: Compared with the PC14 group and PC14-pEGFP-N1 group,PC14-Mst1-pEGFP-N1 population of G1/G0 phase were significantly increased while S and G2/M phase were significantly reduced;The gaps between PC14-Mst1-pEGFP-N1 cells decreased; RT-PCR and Western blot showed that mRNA and protein levels of E-cadherin of PC14-Mst1-pEGFP-N1 were significantly higher than that of PC14,but mRNA and protein levels of Vimentin were significantly lower. CONCLUSION: MSP may affect the cell cycle of PC14 and inhibit its EMT procedure by regulating the expression of related proteins including E-cadherin and Vimentin when RON was not expressed.

[The Correlation Between MicroRNAs in Serum and the Extent of Liver Injury].

OBJECTIVES: To investigate the correlation between the absolute quantification of the microRNAs (miR-122, miR-451, miR-92a, miR-192) in serum during acute liver injury and the extent of liver injury on rat models of CCl4 induced acute liver injury and mice models of acetaminophen (APAP) induced acute liver injury. Furthermore, to investigate the correlation between the absolute quantification of microRNAs in serum and the drug induced liver injury pathological scoring system (DILI-PSS). METHODS: The acute liver injury model in rat by CCl4 (1.5 mL/kg), and the acute liver injury model in mice by APAP (160 mg/kg) were established. The serum at different time points on both models were collected respectively. The absolute quantification of microRNAs in serum were detected by using MiRbayTM SV miRNA Assay kit. Meanwhile, the pathological sections of liver tissue of the mice at each time point were collected to analyze the correlation between microRNAs and the degree of liver injury. RESULTS: In CCl4-induced rat acute liver injury model and APAP induced mouse acute liver injury, miR-122 and miR-192 appeared to be rising significantly, which remained the highest level at 24 h after treatment, and declined to the normal level after 72 h. In CCl4-induced rat acute liver injury model, the change of miR-92a was fluctuated and had no apparent rules, miR-451 declined gradually, but not obviously. In mice acute liver injury model induced by APAP, miR-92a and miR-451 in the progress of liver injury declined gradually, reached the lowest point at 48 h, and then recovered. The result of correlation analysis indicated that miR-122 and miR-192 presented a good positive correlation with the DILI-PSS ( r=0.741 3, P<0.05; r=0.788 3, P<0.01). CONCLUSIONS: The absolute quantification of miR-122 and miR-192 in serum has the highest level in 24 h, then decrease in 72 h, in both drug-induced and chemical liver injury. In addition, both the two microRNAs have good correlation with DILI-PSS in APAP-induced liver injury models.

[Effects of Msp on the Proliferation, Migration and Invasion of Human Non-small Cell Lung Cancer Cells].

OBJECTIVES: To determine the effects of macrophage stimulating protein (Msp) on the proliferation, migration and invasion of human non-small cell lung cancer cells PC14. METHODS: The eukaryotic expression vector for st1was constructed and transfected into Msp(-)and RON(-)human non-small cell lung cancer cells PC14. The expression of st1mRNA in PC14 cells was observed by RT-PCR. The expression levels of Msp protein in PC14, PC14-st1-pEGFP-N1 and PC14-pEGFP-N1 groups as well as the expression of RON in PC14 and SKBR-3 cells were detected by Western blot. RAW264.7 (mouse monocyte macrophage) and SKBR-3 cells were cultured in the supernatant of cells(PC14, PC14-st1-pEGFP-N1and PC14-pEGFP-N1 groups)and tested with Transwell microporous membrane, through which the biologic activity of Msp was evaluated by calculating the cell number migrated. The proliferation of PC14 was measured by MTT assay. The capabilities of PC14 to migrate and invade were measured by Transwell chamber and Matrigel invasion tests, respectively. RESULTS: The expressions of mRNA and protein of Mst1 in PC14 were stable after transfection with Mst1. Msp (PC14-st1 -pEGFP-N1 group) promoted the migration of RON (+) cells (SKBR-3 and RAW264.7). Compared with PC14 and PC14-pEGFP-N1 groups, the proliferation, migration and invasion of PC14 cells in PC14-st1 -pEGFP-N1 group were inhibited significantly. CONCLUSIONS: Msp can promote the migration of RON (+) cancer cells in paracrine secretion manner and inhibit the proliferation, migration and invasion of human non-small cell lung cancer cells PC14 in an unknown way.

Multifunctional Mixed Micelles Cross-Assembled from Various Polyurethanes for Tumor Therapy.

A challenge in the development of multifunctional drug delivery systems is to establish a reasonable and effective synthetic route for multifunctional polymer preparation. Herein, we propose a unique protocol to prepare multifunctional micelles by a cross-assembly process using three different functional polyurethanes incorporating acidic sensitive hydrazone, folic acid for active targeting, and gemini quaternary ammonium (GQA) as efficient cell uptake ligands, respectively. These multifunctional mixed micelles (GFHPMs) have been endowed tunable particle sizes and zeta potential and a unique three-order-layer cross-assemble structure. Their drug-loading contents have been significantly improved, and drug release profiles displayed controlled release of their payloads under acid condition. The folate and GQA ligands showed a synergistic effect to enhance the cell uptake. Biodistribution and antitumor effect of these micelles were systematically investigated in vivo, the mixed micelles could penetrate into the depths of tumors, and drug concentrations in tumors reached the maximum of 6.5% ID/g at 24 h, resulting in an excellent therapeutic effect that the volumes of tumors treated with GFHPM are five times smaller than those treated with blank micelles. Our present work provides an effective approach to the design of multifunctional nanocarriers for tumor-targeted and programmed intracellular drug delivery.

[Expression of Myocardial Specificity Markers MEF-2C and Cx43 in Rat Bone Marrow-derived Mesenchymal Stem Cells Induced by Electrical Stimulation In Vitro].

Bone marrow-derived mesenchymal stem cells (BMSCs) for repairing damaged heart tissue are a new kind of important treatment options because of their potential to differentiate into cardiomyocytes. We in this experiment investigated the effect of different electrical stimulation time on the expression of myocardial specificity gene and protein in rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. The rBMSCs of second or third generation were randomly divided into three groups, i.e, electrical stimulation (ES) group, 5-Azacytidine (5-Aza) group and the control group. The rBMSCs in the ES groups with complete medium were exposed to 2 V, 2 Hz, 5 ms electrical stimulation for 0. 5 h, 2 h, 4 h, and 6 h respectively every day for 10 days. Those in the 5-Aza group were induced by 5-Aza (10 µmol/L) for 24 h, and then cultured with complete medium for 10 days. Those in the control group were only cultured with complete medium, without any treatment, for 10 days. The rBMSCs' morphological feature in each group was observed with inverted phase microscope. The mRNA expression of myocyte-specific enhancer factor 2C (MEF-2C) and connexin 43 (Cx43) were examined with Real-Time quantitative PCR and the protein expression of MEF-2C, Cx43 were detected with Western Blot method. The results showed that the mRNA expression level of the MEF-2C, Cx43 and the protein expression level of MEF-2C, Cx43 were significantly higher in the ES group and 5-Aza group than those in the relative control group (P < 0.05). It suggests that electrical stimulation could play a part of role in the induction of the rBMSCs to differentiate into the cariomyocyte-like cells in vitro and the effectiveness of the electrical stimulation with 2 h/d had the best in our experiment. But the mechanism how electrical stimulation promotes the differentiation of rBMSC into cardiomyocyte is still unclear.

Cell internalizable and intracellularly degradable cationic polyurethane micelles as a potential platform for efficient imaging and drug delivery.

A cell internalizable and intracellularly degradable micellar system, assembled from multiblock polyurethanes bearing cell-penetrating gemini quaternary ammonium pendent groups in the side chain and redox-responsive disulfide linkages throughout the backbone, was developed for potential magnetic resonance imaging (MRI) and drug delivery. The nanocarrier is featured as a typical "cleavable core-internalizable shell-protective corona" architecture, which exhibits small size, positive surface charge, high loading capacity, and reduction-triggered destabilization. Furthermore, it can rapidly enter tumor cells and release its cargo in response to an intracellular level of glutathione, resulting in enhanced drug efficacy in vitro. The magnetic micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles demonstrate excellent MRI contrast enhancement, with T2 relaxivity found to be affected by the morphology of SPIO-clustering inside the micelle core. The multifunctional carrier with good cytocompatibility and nontoxic degradation products can serve as a promising theranostic candidate for efficient intracellular delivery of anticancer drugs and real-time monitoring of therapeutic effect.

[Differentiation of rat bone marrow-derived mesenchymal stem cells into cardiomyocyte-like cells induced by cyclic stretching strain].

Bone marrow-derived mesenchymal stem cells (BMSCs) are multipotent stem cells that differentiate into a variety of cell types and widely used in tissue regeneration engineering. The purpose of this study is to investigate whether the cyclic biaxial stretching strain could promote the rat BMSCs (rBMSCs) to differentiate into cardiomyocyte-like cells in vitro. The second or third generation of rBMSCs were randomly divided into the cyclic stretching stain group, the control group and the blank group. Those rBMSCs in the cyclic stretching strain group were seeded on a silicone membrane with complete medium were exposed to biaxial stretching strain of 10% of membrane at a frequency of 1 Hz lasting for 6 h, 12 h and 24 h. Those in the control group were seeded on silicone membrane with complete medium. Those in the blank group were seeded in the 6-wells plates with complete medium. The mRNA expression of GATA4 and myocyte-specific enhancer factor 2C (MEF-2C) were detected by the real-time fluorescent quantification PCR and the protein expression of connexin 43 (Cx43) was detected by using the Western blot method. The results showed that the mRNA expression level of the GATA4 and MEF-2C, and the protein expression level of Cx43 were significantly higher in the cyclic stretching strain groups, compared with those in the relative control groups (P < 0.05). It suggests that cyclic biaxial stretching strain could play a part in the induction of rBMSCs to differentiate into cardiomyocyte-like cells in vitro, but the differentiation mechanism is still unclear.

Single-Cell Transcriptomics Reveals the Ameliorative Effect of Oridonin on Septic Liver Injury.

Sepsis is a life-threatening syndrome leading to hemodynamic instability and potential organ dysfunction. Oridonin, commonly used in Traditional Chinese Medicine (TCM), exhibits significant anti-inflammation activity. To explore the protective mechanisms of oridonin against the pathophysiological changes, the authors conducted single-cell transcriptome (scRNA-seq) analysis on septic liver models induced by cecal ligation and puncture (CLP). They obtained a total of 63,486 cells, distributed across 11 major cell clusters, and concentrated their analysis on four specific clusters (hepatocytes/Heps, macrophages, endothelial/Endos and T/NK) based on their changes in proportion during sepsis and under oridonin treatment. Firstly, biological changes in Hep, which are related to metabolic dysregulation and pro-inflammatory signaling, are observed during sepsis. Secondly, they uncovered the dynamic profiles of macrophage's phenotype, indicating that a substantial number of macrophages exhibited a M1-skewed phenotype associated with pro-inflammatory characteristics in septic model. Thirdly, they detected an upregulation of both inflammatory cytokines and transcriptomic factor Nfkb1 expression within Endo, along with slight capillarization during sepsis. Moreover, excessive accumulation of cytotoxic NK led to an immune imbalance. Though, oridonin ameliorated inflammatory-related responses and improved the liver dysfunction in septic mice. This study provides fundamental evidence of the protective effects of oridonin against sepsis-induced cytokine storm.

Cross-linking manipulation of waterborne biodegradable polyurethane for constructing mechanically adaptable tissue engineering scaffolds.

Mechanical adaptation of tissue engineering scaffolds is critically important since natural tissue regeneration is highly regulated by mechanical signals. Herein, we report a facile and convenient strategy to tune the modulus of waterborne biodegradable polyurethanes (WBPU) via cross-linking manipulation of phase separation and water infiltration for constructing mechanically adaptable tissue engineering scaffolds. Amorphous aliphatic polycarbonate and trifunctional trimethylolpropane were introduced to polycaprolactone-based WBPUs to interrupt interchain hydrogen bonds in the polymer segments and suppress microphase separation, inhibiting the crystallization process and enhancing covalent cross-linking. Intriguingly, as the crosslinking density of WBPU increases and the extent of microphase separation decreases, the material exhibits a surprisingly soft modulus and enhanced water infiltration. Based on this strategy, we constructed WBPU scaffolds with a tunable modulus to adapt various cells for tissue regeneration and regulate the immune response. As a representative application of brain tissue regeneration model in vivo, it was demonstrated that the mechanically adaptable WBPU scaffolds can guide the migration and differentiation of endogenous neural progenitor cells into mature neurons and neuronal neurites and regulate immunostimulation with low inflammation. Therefore, the proposed strategy of tuning the modulus of WBPU can inspire the development of novel mechanically adaptable biomaterials, which has very broad application value.

Osteogenic differentiation of bone mesenchymal stem cells on linearly aligned triangular micropatterns.

Mesenchymal stem cells (MSCs) hold promise for regenerative medicine, particularly for bone tissue engineering. However, directing MSC differentiation towards specific lineages, such as osteogenic, while minimizing undesired phenotypes remains a challenge. Here, we investigate the influence of micropatterns on the behavior and lineage commitment of rat bone marrow-derived MSCs (rBMSCs), focusing on osteogenic differentiation. Linearly aligned triangular micropatterns (TPs) and circular micropatterns (CPs) coated with fibronectin were fabricated to study their effects on rBMSC morphology and differentiation and the underlying mechanobiological mechanisms. TPs, especially TP15 (15 µm), induced the cell elongation and thinning, while CPs also promoted the cell stretching, as evidenced by the decreased circularity and increased aspect ratio. TP15 significantly promoted osteogenic differentiation, with increased expression of osteogenic genes (Runx2, Spp1, Alpl, Bglap, Col1a1) and decreased expression of adipogenic genes (Pparg, Cebpa, Fabp4). Conversely, CPs inhibited both osteogenic and adipogenic differentiation. Mechanistically, TP15 increased Piezo1 activity, cytoskeletal remodeling including the aggregates of F-actin and myosin filaments at the cell periphery, YAP1 nuclear translocation, and integrin upregulation. Piezo1 inhibition suppressed the osteogenic genes expression, myosin remodeling, and YAP1 nuclear translocation, indicating Piezo1-mediated the mechanotransduction in rBMSCs on TPs. TP15 also induced osteogenic differentiation of BMSCs from aging rats, with upregulated Piezo1 and nuclear translocation of YAP1. Therefore, triangular micropatterns, particularly TP15, promote osteogenesis and inhibit adipogenesis of rBMSCs through Piezo1-mediated myosin and YAP1 pathways. Our study provides novel insights into the mechanobiological mechanisms governing MSC behaviors on micropatterns, offering new strategies for tissue engineering and regenerative medicine.