Regulation of cardiac fibroblasts reprogramming into cardiomyocyte-like cells with a cocktail of small molecule compounds.

Myocardial infarction results in extensive cardiomyocyte apoptosis, leading to the formation of noncontractile scar tissue. Given the limited regenerative capacity of adult mammalian cardiomyocytes, direct reprogramming of cardiac fibroblasts (CFs) into cardiomyocytes represents a promising therapeutic strategy for myocardial repair, and small molecule drugs might offer a more attractive alternative to gene editing approaches in terms of safety and clinical feasibility. This study aimed to reprogram rat CFs into cardiomyocytes using a small molecular chemical mixture comprising CHIR99021, Valproic acid, Dorsomorphin, SB431542, and Forskolin. Immunofluorescence analysis revealed a significant increase in the expression of cardiomyocyte-specific markers, including cardiac troponin T (cTnT), Connexin 43 (Cx43), α-actinin, and Tbx5. Changes in intracellular calcium ion levels and Ca2+ signal transfer between adjacent cells were monitored using a calcium ion fluorescence probe. mRNA sequencing analysis demonstrated the upregulation of genes associated with cardiac morphogenesis, myocardial differentiation, and muscle fiber contraction during CF differentiation induced by the small-molecule compounds. Conversely, the expression of fibroblast-related genes was downregulated. These findings suggest that chemical-induced cell fate conversion of rat CFs into cardiomyocyte-like cells is feasible, offering a potential therapeutic solution for myocardial injury.

Extravascular administration of IGF1R antagonists protects against aortic aneurysm in rodent and porcine models.

An abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease. We identified plasma insulin-like growth factor 1 (IGF1) as an independent risk factor in patients with AAA by correlating plasma IGF1 with risk. Smooth muscle cell- or fibroblast-specific knockout of Igf1r, the gene encoding the IGF1 receptor (IGF1R), attenuated AAA formation in two mouse models of AAA induced by angiotensin II infusion or CaCl2 treatment. IGF1R was activated in aortic aneurysm samples from human patients and mice with AAA. Systemic administration of IGF1C, a peptide fragment of IGF1, 2 weeks after disease development inhibited AAA progression in mice. Decreased AAA formation was linked to competitive inhibition of IGF1 binding to its receptor by IGF1C and modulation of downstream alpha serine/threonine protein kinase (AKT)/mammalian target of rapamycin signaling. Localized application of an IGF1C-loaded hydrogel was developed to reduce the side effects observed after systemic administration of IGF1C or IGF1R antagonists in the CaCl2-induced AAA mouse model. The inhibitory effect of the IGF1C-loaded hydrogel administered at disease onset on AAA formation was further evaluated in a guinea pig-to-rat xenograft model and in a sheep-to-minipig xenograft model of AAA formation. The therapeutic efficacy of IGF1C for treating AAA was tested through extravascular delivery in the sheep-to-minipig model with AAA established for 2 weeks. Percutaneous injection of the IGF1C-loaded hydrogel around the AAA resulted in improved vessel flow dynamics in the minipig aorta. These findings suggest that extravascular administration of IGF1R antagonists may have translational potential for treating AAA.

Trilayered biomimetic hydrogel scaffolds with dual-differential microenvironment for articular osteochondral defect repair.

Commonly, articular osteochondral tissue exists significant differences in physiological architecture, mechanical function, and biological microenvironment. However, the development of biomimetic scaffolds incorporating upper cartilage, middle tidemark-like, and lower subchondral bone layers for precise articular osteochondral repair remains elusive. This study proposed here a novel strategy to construct the trilayered biomimetic hydrogel scaffolds with dual-differential microenvironment of both mechanical and biological factors. The cartilage-specific microenvironment was achieved through the grafting of kartogenin (KGN) into gelatin via p-hydroxyphenylpropionic acid (HPA)-based enzyme crosslinking reaction as the upper cartilage layer. The bone-specific microenvironment was achieved through the grafting of atorvastatin (AT) into gelatin via dual-crosslinked network of both HP-based enzyme crosslinking and glycidyl methacrylate (GMA)-based photo-crosslinking reactions as the lower subchondral bone layer. The introduction of tidemark-like middle layer is conducive to the formation of well-defined cartilage-bone integrated architecture. The in vitro experiments demonstrated the significant mechanical difference of three layers, successful grafting of drugs, good cytocompatibility and tissue-specific induced function. The results of in vivo experiments also confirmed the mechanical difference of the trilayered bionic scaffold and the ability of inducing osteogenesis and chondrogenesis. Furthermore, the articular osteochondral defects were successfully repaired using the trilayered biomimetic hydrogel scaffolds by the activation of endogenous recovery, which offers a promising alternative for future clinical treatment.

Immunological Mechanisms behind Anti-PD-1/PD-L1 Immune Checkpoint Blockade: Intratumoral Reinvigoration or Systemic Induction?

Anti-PD-1/PD-L1 immune checkpoint blockade (ICB) has been widely used to treat many types of cancer. It is well established that PD-L1 expressing cancer cells could directly inhibit the cytotoxicity of PD-1+ T cells via PD-L1-PD-1 interaction. However, histological quantification of intratumoral PD-L1 expression provides limited predictive value and PD-L1 negative patients could still benefit from ICB treatment. Therefore, the current major clinical challenges are low objective response rate and unclear immunological mechanisms behind responding vs. non-responding patients. Here, we review recent studies highlighting the importance of longitudinal pre- and post-ICB treatment on patients with various types of solid tumor to elucidate the mechanisms behind ICB treatment. On one hand, ICB induces changes in the tumor microenvironment by reinvigorating intratumoral PD-1+ exhausted T cells ("releasing the brakes"). On the other hand, ICB can also affect systemic antitumor immunity in the tumor-draining lymph node to induce priming/activation of cancer specific T cells, which is evident by T cell clonal expansion/replacement in peripheral blood. These studies reveal that ICB treatment not only acts on the tumor microenvironment ("battlefield") but also acts on immune organs ("training camp") of patients with solid tumors. A deeper understanding of the immunological mechanisms behind ICB treatment will pave the way for further improvements in clinical response.

PD-L1-expressing tumor-associated macrophages are immunostimulatory and associate with good clinical outcome in human breast cancer.

Tumor-associated macrophages (TAMs) are the predominant cells that express programmed cell death ligand 1 (PD-L1) within human tumors in addition to cancer cells, and PD-L1+ TAMs are generally thought to be immunosuppressive within the tumor immune microenvironment (TIME). Using single-cell transcriptomic and spatial multiplex immunofluorescence analyses, we show that PD-L1+ TAMs are mature and immunostimulatory with spatial preference to T cells. In contrast, PD-L1- TAMs are immunosuppressive and spatially co-localize with cancer cells. Either higher density of PD-L1+ TAMs alone or ratio of PD-L1+/PD-L1- TAMs correlate with favorable clinical outcome in two independent cohorts of patients with breast cancer. Mechanistically, we show that PD-L1 is upregulated during the monocyte-to-macrophage maturation and differentiation process and does not require external IFN-γ stimulus. Functionally, PD-L1+ TAMs are more mature/activated and promote CD8+ T cells proliferation and cytotoxic capacity. Together, our findings reveal insights into the immunological significance of PD-L1 within the TIME.

Therapeutic effect of adipose-derived stem cells injected into pericardial cavity in rat heart failure.

AIMS: There are few studies on the treatment of heart failure by injecting stem cells into the pericardial cavity. Can the cells injected into the pericardial cavity migrate through the epicardium to the myocardial tissue? Whether there is therapeutic effect and the mechanism of therapeutic effect are still unclear. This study investigated the therapeutic efficacy and evidence of cell migration of adipose-derived stem cells (ADSCs) injected into the pericardial cavity in rat heart failure. The aim of this study is to demonstrate the effectiveness and mechanism of treating heart failure by injecting stem cells into the pericardial cavity, laying an experimental foundation for a new approach to stem cell therapy for heart disease in clinical practice. METHODS AND RESULTS: The inguinal adipose tissue of male SD rats aged 4-6 weeks was taken, ADSCs were isolated and cultured, and their stem cell surface markers were identified. Forty rats aged 6-8 weeks were divided into sham operation group, heart failure group, and treatment group; there were 15 rats in the heart failure group and 15 rats in the treatment group. The heart failure model was established by intraperitoneal injection of adriamycin hydrochloride. The heart function of the three groups was detected by small animal ultrasound. The model was successful if the left ventricular ejection fraction < 50%. The identified ADSCs were injected into the pericardial cavity of rats in the treatment group. The retention of transplanted cells in pericardial cavity was detected by small animal in vivo imaging instrument, and the migration of transplanted cells into myocardial tissue was observed by tissue section and immunofluorescence. Western blotting and immunohistochemical staining were used to detect brain natriuretic peptide (BNP), α-smooth muscle actin (α-SMA), and C-reactive protein (CRP). ADSCs express CD29, CD44, and CD73. On the fourth day after injection of ADSCs into pericardial cavity, they migrated to myocardial tissue through epicardium and gradually diffused to deep myocardium. The cell density in the pericardial cavity remains at a high level for 10 days after injection and gradually decreases after 10 days. Compared with the heart failure group, the expression of BNP and α-SMA decreased (P < 0.05 and P < 0.001, respectively), and the expression of CRP in the treatment group was higher than that in the heart failure group (P < 0.0001). A small amount of BNP, α-SMA, and CRP was expressed in the myocardium of the sham operation group. After injection of ADSCs, interleukin-6 in myocardial tissue was significantly lower than that in heart failure myocardium (P < 0.01). After treatment, vascular endothelial growth factor A was significantly higher than that of heart failure (P < 0.01). CONCLUSIONS: Pericardial cavity injected ADSCs can penetrate the epicardium, migrate into the myocardium, and have a therapeutic effect on heart failure. Their mechanism of action is to exert therapeutic effects through anti-inflammatory, anti-fibrosis, and increased angiogenesis.

Construct Robust Epitaxial Growth of (101) Textured Zinc Metal Anode for Long Life and High Capacity in Mild Aqueous Zinc-Ion Batteries.

Aqueous zinc-metal batteries are considered to have the potential for energy storage due to their high safety and low cost. However, the practical applications of zinc batteries are limited by dendrite growth and side reactions. Epitaxial growth is considered an effective method for stabilizing Zn anode, especially for manipulating the (002) plane of deposited zinc. However, (002) texture zinc is difficult to achieve stable cycle at high capacity due to its large lattice distortion and uneven electric field distribution. Here, a novel zinc anode with highly (101) texture (denoted as (101)-Zn) is constructed. Due to unique directional guidance and strong bonding effect, (101)-Zn can achieve dense vertical electroepitaxy in near-neutral electrolytes. In addition, the low grain boundary area inhibits the occurrence of side reactions. The resultant (101)-Zn symmetric cells exhibit excellent stability over 5300 h (4 mA cm-2 for 2 mAh cm-2 ) and 330 h (15 mA cm-2 for 10 mAh cm-2 ). Meanwhile, the cycle life of Zn//MnO2 full cell is meaningfully improved over 1000 cycles.

Unlocking the Capacity of Bismuth Oxide by a Redox Mediator Strategy for High-Performance Aqueous Zn-Ion Batteries.

Many cathode materials store zinc ions based on the intercalation reaction mechanism in neutral aqueous Zn-ion batteries, and the structural design of the cathodes has been stuck in the curing mode by extending the ion diffusion channel. Here, we first develop halide ions to unlock the electrochemical activity of conversion-type Bi2O3 in aqueous Zn-ion batteries. Notably, the iodide ion shows the best performance compatibility with the Bi2O3 cathode. The electrochemical reaction mechanism studies show that iodide ions can be regarded as a redox medium to reduce the charge-transfer activation energy and motivate the conversion of Bi2O3 from Bi3+ to Bi0 during the cycle. Unsurprising, the discharge-specific capacity can reach 436.8 mAh g-1 at 0.5 A g-1 and achieve a cyclic lifespan of 6000 cycles at a current density of 3 A g-1. The activation of the Bi2O3 conversion reaction by iodide ions is of great significance for broadening the research range of ZIB cathode materials.

Virtual Screening and Binding Analysis of Potential CD58 Inhibitors in Colorectal Cancer (CRC).

Human cell surface receptor CD58, also known as lymphocyte function-associated antigen 3 (LFA-3), plays a critical role in the early stages of immune response through interacting with CD2. Recent research identified CD58 as a surface marker of colorectal cancer (CRC), which can upregulate the Wnt pathway and promote self-renewal of colorectal tumor-initiating cells (CT-ICs) by degradation of Dickkopf 3. In addition, it was also shown that knockdown of CD58 significantly impaired tumor growth. In this study, we developed a structure-based virtual screening pipeline using Autodock Vina and binding analysis and identified a group of small molecular compounds having the potential to bind with CD58. Five of them significantly inhibited the growth of the SW620 cell line in the following in vitro studies. Their proposed binding models were further verified by molecular dynamics (MD) simulations, and some pharmaceutically relevant chemical and physical properties were predicted. The hits described in this work may be considered interesting leads or structures for the development of new and more efficient CD58 inhibitors.

mRNA sequencing reveals the distinct gene expression and biological functions in cardiac fibroblasts regulated by recombinant fibroblast growth factor 2.

After myocardial injury, cardiac fibroblasts (CFs) differentiate into myofibroblasts, which express and secrete extracellular matrix (ECM) components for myocardial repair, but also promote myocardial fibrosis. Recombinant fibroblast growth factor 2 (FGF2) protein drug with low molecular weight can promote cell survival and angiogenesis, and it was found that FGF2 could inhibit the activation of CFs, suggesting FGF2 has great potential in myocardial repair. However, the regulatory role of FGF2 on CFs has not been fully elucidated. Here, we found that recombinant FGF2 significantly suppressed the expression of alpha smooth muscle actin (α-SMA) in CFs. Through RNA sequencing, we analyzed mRNA expression in CFs and the differently expressed genes regulated by FGF2, including 430 up-regulated genes and 391 down-regulated genes. Gene ontology analysis revealed that the differentially expressed genes were strongly enriched in multiple biological functions, including ECM organization, cell adhesion, actin filament organization and axon guidance. The results of gene set enrichment analysis (GSEA) show that ECM organization and actin filament organization are down-regulated, while axon guidance is up-regulated. Further cellular experiments indicate that the regulatory functions of FGF2 are consistent with the findings of the gene enrichment analysis. This study provides valuable insights into the potential therapeutic role of FGF2 in treating cardiac fibrosis and establishes a foundation for further research to uncover the underlying mechanisms of CFs gene expression regulated by FGF2.

Progress and Challenges of Immunotherapy Predictive Biomarkers for Triple Negative Breast Cancer in the Era of Single-Cell Multi-Omics.

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer with a poor prognosis. Despite conventional treatments, including surgery, radiation, and chemotherapy, the overall response rate to PD-1/PD-L1 immune checkpoint inhibitors remains low, with limited predictive significance from current biomarkers such as PD-L1 expression, tumor-infiltrating lymphocytes (TILs), and tumor mutational burden (TMB). To address this challenge, recent advancements in single-cell sequencing techniques have enabled deeper exploration of the highly complex and heterogeneous TNBC tumor microenvironment at the single-cell level, revealing promising TNBC predictive biomarkers for immune checkpoint inhibitors. In this review, we discuss the background, motivation, methodology, results, findings, and conclusion of multi-omics analyses that have led to the identification of these emerging biomarkers. Our review suggests that single-cell multi-omics analysis holds great promise for the identification of more effective biomarkers and personalized treatment strategies for TNBC patients.

Large animal models for cardiac remuscularization studies: A methodological review.

Myocardial infarction is the most common cause of heart failure, one of the most fatal non-communicable diseases worldwide. The disease could potentially be treated if the dead, ischemic heart tissues are regenerated and replaced with viable and functional cardiomyocytes. Pluripotent stem cells have proven the ability to derive specific and functional cardiomyocytes in large quantities for therapy. To test the remuscularization hypothesis, the strategy to model the disease in animals must resemble the pathophysiological conditions of myocardial infarction as in humans, to enable thorough testing of the safety and efficacy of the cardiomyocyte therapy before embarking on human trials. Rigorous experiments and in vivo findings using large mammals are increasingly important to simulate clinical reality and increase translatability into clinical practice. Hence, this review focus on large animal models which have been used in cardiac remuscularization studies using cardiomyocytes derived from human pluripotent stem cells. The commonly used methodologies in developing the myocardial infarction model, the choice of animal species, the pre-operative antiarrhythmics prophylaxis, the choice of perioperative sedative, anaesthesia and analgesia, the immunosuppressive strategies in allowing xenotransplantation, the source of cells, number and delivery method are discussed.

MicroRNA-494 regulates high glucose-induced cardiomyocyte apoptosis and autophagy by PI3K/AKT/mTOR signalling pathway.

AIMS: Diabetic cardiomyopathy (DCM) is one of the major cardiovascular complications of diabetes. However, the mechanism of DCM is not fully understood. Studies have confirmed that certain microRNAs (miRNAs/miRs) are key regulators of DCM. The aim of this study was to investigate the role and mechanism of microRNA (miR)-494 in cardiomyocyte apoptosis and autophagy induced by high glucose (HG). METHODS AND RESULTS: By establishing a rat DCM model and an HG-treated H9c2 cells injury model, cardiac function was detected by echocardiography, myocardial tissue was stained by immunohistochemistry, and Cell Counting Kit-8 assay and lactate dehydrogenase assay were used to detect the cardiomyocyte injury. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labelling staining, and western blotting was used to detect death and autophagy. The results showed that the expression level of miR-494 was higher in the myocardial tissue of DCM rats and the myocardial cells of H9c2 treated with HG. Compared with the corresponding negative control groups, miR-494 mimics enhanced HG-induced apoptosis and autophagy, whereas miR-494 inhibitors showed the opposite effect, corresponding PI3K, AKT, and mTOR phosphorylation level has changed. CONCLUSIONS: These findings identify that miR-494 could regulate cell apoptosis and autophagy through PI3K/AKT/mTOR signalling pathway, participating in the regulation of cardiomyocyte cell damage after HG. These findings provide new insights for the further study of the molecular mechanism and treatment of DCM.

Design, synthesis, and evaluation of JTE-013 derivatives as novel potent S1PR2 antagonists for recovering the sensitivity of colorectal cancer to 5-fluorouracil.

Targeting sphingosine-1-phosphate receptor 2 (S1PR2) has been proved as a promising strategy to reverse 5-fluorouracil (5-FU) resistance. Here, we report the discovery of the novel JTE-013 derivative compound 37 h as a more effective S1PR2 antagonist to reverse 5-FU resistance in SW620/5-FU and HCT116DPD cells than JTE-013 and previously reported compound 5. Compound 37 h could effectively bind S1PR2 and reduce its expression, thus leading to decreased expression of JMJD3 and dihydropyrimidine dehydrogenase (DPD), while also increasing the level of H3K27me3 to decrease the degradation of 5-FU and thereby increase its intracellular concentration in SW620/5-FU, HCT116DPD, and L02 cells. Furthermore, compound 37 h showed good selectivity to other S1PRs and normal colon cell line NCM460. Western blot analysis demonstrated that compound 37 h could abrogate the FBAL-stimulated upregulation of DPD expression by S1PR2. Importantly, compound 37 h also showed favorable metabolic stability with a long half-life (t1/2) of 7.9 h. Moreover, compound 37 h significantly enhanced the antitumor efficacy of 5-FU in the SW620/5-FU animal model. Thus, the JTE-013-based derivative compound 37 h represents a promising lead compound for the development of novel 5-FU sensitizers for colorectal cancer (CRC) therapy.

Rational Design, Synthesis, and Biological Evaluation of Novel S1PR2 Antagonists for Reversing 5-FU-Resistance in Colorectal Cancer.

Resistance to 5-FU reduces its clinical efficacy for the treatment of colorectal cancer. Sphingosine-1-phosphate receptor 2 (S1PR2) has emerged as a potential target to reverse 5-FU-resistance by inhibiting the expression of dihydropyrimidine dehydrogenase (DPD). In this study, 38 novel S1PR2 antagonists based on aryl urea structure were designed and synthesized, and the structure-activity relationship was investigated based on the S1PR2 binding assay. Representative compound 43 potently interacts with S1PR2 with a KD value of 0.73 nM. It displays potent 5-FU resensitizing activity in multiple 5-FU-resistant tumor cell lines, particularly in SW620/5-FU (EC50 = 1.99 ± 0.03 µM) but shows no cytotoxicity in the normal colon cell line NCM460 up to 1000 µM. Moreover, 43 significantly enhances the antitumor efficacy of 5-FU in the SW620/5-FU animal model. These data suggest that 43 could be a novel lead compound for developing a 5-FU resensitizing agent.

Interaction of KCNA5, CX43, and CX40 proteins in the atrial muscle of patients with atrial fibrillation.

The objective of the study was to investigate the expression levels of potassium voltage-gated channel subfamily A member 5 (KCNA5), connexin 43 (Cx43), and connexin 40 (Cx40) in the left atrial appendage of patients with atrial fibrillation (AF) and the interactions between them. We gathered tissue samples from patients with persistent AF and sinus rhythm and used fluorescence quantitative polymerase chain reaction to evaluate messenger RNA (mRNA) changes of KCNA5, Cx43, and Cx40. Then, we studied the protein levels of KCNA5, Cx43, and Cx40 by immunofluorescence and western blot analysis and the interactions between these proteins were identified by immunoprecipitation and immunofluorescence colocation, respectively. Compared with the control group, the mRNA and protein levels of KCNA5, Cx43, and Cx40 in the AF group were decreased and the positive expression of KCNA5, Cx43, and Cx40 protein was also decreased by immunofluorescence staining in the AF group. In addition, immunoprecipitation and immunofluorescence colocation revealed that KCNA5 was coexpressed with Cx43 and Cx40 proteins. The expressions of KCNA5, Cx43, and Cx40 were substantially downregulated in the myocardium of patients with AF and KCNA5 interacted with Cx43 and Cx40 proteins, respectively.

STAT4 regulates cardiomyocyte apoptosis in rat models of diabetic cardiomyopathy.

OBJECTIVE: This study aimed to investigate the protective role of the signal transducer and activator of transcription 4 (STAT4) in diabetic cardiomyopathy. MATERIALS AND METHODS: Male Sprague-Dawley (SD) rats (6-8 weeks old) were purchased from the Experimental Animal Center of Zhengzhou University. The rats were randomly divided into the control and diabetic cardiomyopathy groups. Rat models of diabetic cardiomyopathy were established by a high-sugar and high-fat diet combined with a peritoneal injection of streptozocin. Pathological changes in the heart were visualized using Hematoxylin-eosin (HE) staining and Masson's staining. Moreover, cell apoptosis was detected using terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling (TUNEL) staining and Annexin V apoptosis detection kit. Furthermore, H9C2 cells were transfected with lentivirus overexpressing STAT4 and treated with high glucose. The CCK-8 assay was performed to determine cell viability. Finally, Western blotting was used to determine the expression of STAT4, Bax, and Bcl-2. RESULTS: The myocardial tissue of the diabetic cardiomyopathy models showed hypertrophy, myocardial fibrosis and collagen deposition. Furthermore, TUNEL staining showed increased apoptosis and decreased expression of STAT4 in the myocardial cells. Moreover, the myocardial tissues of the DCM models showed increased expression of Bax/Bcl-2 and a high percentage of Annexin V positive cells. The H9C2 cells showed decreased expression of STAT4 following high glucose treatment. However, the H9C2 cells overexpressing STAT4 showed decreased expression of Bax/Bcl-2 and reduced percentage of Annexin V positive cells. CONCLUSION: The DCM group had decreased myocardial expression of STAT4. Furthermore, overexpression of STAT4 was shown to reduce high glucose-induced apoptosis.

The sustained PGE2 release matrix improves neovascularization and skeletal muscle regeneration in a hindlimb ischemia model.

BACKGROUND: The promising therapeutic strategy for the treatment of peripheral artery disease (PAD) is to restore blood supply and promote regeneration of skeletal muscle regeneration. Increasing evidence revealed that prostaglandin E2 (PGE2), a lipid signaling molecule, has significant therapeutic potential for tissue repair and regeneration. Though PGE2 has been well reported in tissue regeneration, the application of PGE2 is hampered by its short half-life in vivo and the lack of a viable system for sustained release of PGE2. RESULTS: In this study, we designed and synthesized a new PGE2 release matrix by chemically bonding PGE2 to collagen. Our results revealed that the PGE2 matrix effectively extends the half-life of PGE2 in vitro and in vivo. Moreover, the PGE2 matrix markedly improved neovascularization by increasing angiogenesis, as confirmed by bioluminescence imaging (BLI). Furthermore, the PGE2 matrix exhibits superior therapeutic efficacy in the hindlimb ischemia model through the activation of MyoD1-mediated muscle stem cells, which is consistent with accelerated structural recovery of skeletal muscle, as evidenced by histological analysis. CONCLUSIONS: Our findings highlight the chemical bonding strategy of chemical bonding PGE2 to collagen for sustained release and may facilitate the development of PGE2-based therapies to significantly improve tissue regeneration.

Novel 5-fluorouracil sensitizers for colorectal cancer therapy: Design and synthesis of S1P receptor 2 (S1PR2) antagonists.

Sphingosine-1-phosphate receptor 2 (S1PR2) has been identified as a brand-new GPCR target for designing antagonists to reverse 5-FU resistance. We herein report the structural optimization and structure-activity relationship of JTE-013 derivatives as S1PR2 antagonists. Compound 9d was the most potent S1PR2 antagonist (KD = 34.8 nM) among developed compounds. Here, compound 9d could significantly inhibit the expression of dihydropyrimidine dehydrogenase (DPD) to reverse 5-FU-resistance in HCT116DPD and SW620/5-FU cells. Further mechanism studies demonstrated that compound 9d not only inhibited S1PR2 but also affected the transcription of S1PR2. In addition, compound 9d also showed acceptable selectivity to normal cells (NCM460). Importantly, compound 9d with suitable pharmacokinetic properties could significantly reverse 5-FU-resistance in the HCT116DPD and SW620/5-FU xenograft models without obvious toxicity, in which the inhibition rates of 5-FU were increased from 23.97% to 65.29% and 27.23% to 60.81%, respectively. Further immunohistochemistry and western blotting analysis also demonstrated that compound 9d significantly decreases the expression of DPD in tumor and liver tissues. These results indicated that compound 9d is a promising lead compound to reverse 5-FU-resistance for colorectal cancer therapy.