A dendritic cell-recruiting, antimicrobial blood clot hydrogel for melanoma recurrence prevention and infected wound management.

Surgical resection, the mainstay for melanoma treatment, faces challenges due to high tumor recurrence rates and complex postoperative wound healing. Chronic inflammation from residual disease and the risk of secondary infections impede healing. We introduce an innovative, injectable hydrogel system that integrates a multifaceted therapeutic approach. The hydrogel, crosslinked by calcium ions with sodium alginate, encapsulates a blood clot rich in dendritic cells (DCs) chemoattractants and melanoma cell-derived nanovesicles (NVs), functioning as a potent immunostimulant. This in situ recruitment strategy overcomes the limitations of subcutaneous tumor vaccine injections and more effectively achieves antitumor immunity. Additionally, the hydrogel incorporates Chlorella extracts, enhancing its antimicrobial properties to prevent wound infections and promote healing. One of the key findings of our research is the dual functionality of Chlorella extracts; they not only expedite the healing process of infected wounds but also increase the hydrogel's ability to stimulate an antitumor immune response. Given the patient-specific nature of the blood clot and NVs, our hydrogel system offers customizable solutions for individual postoperative requirements. This personalized approach is highlighted by our study, which demonstrates the synergistic impact of the composite hydrogel on preventing melanoma recurrence and hastening wound healing, potentially transforming postsurgical melanoma management.

Stat3 confers resistance against hypoxia/reoxygenation-induced oxidative injury in hepatocytes through upregulation of Mn-SOD.

BACKGROUND/AIMS: Hypoxia/reoxygenation (H/R) causes oxidative stress to the cell and induces apoptotic cell death. Signal transducer and activator of transcription-3 (Stat3) is one of the most important molecules involved in the initiation of liver development and regeneration, and has recently been shown to protect cells against various pathogens. In order to investigate the hepatoprotective effects of Stat3, we examined whether it protects against H/R-induced injury in primary hepatocytes. METHODS: Primary cultured hepatocytes were prepared from SD rats. Adenoviruses and cytokines were added 2 days and 1h prior to the H/R insult, respectively. Hepatocytes and culture media were harvested for the assays before and after H/R insult. RESULTS: Interleukin-6 and cardiotropin-1, which may function mainly through Stat3 activation, protected cells from H/R-induced apoptosis. Adenoviral overexpression of the constitutively activated form of Stat3 (Stat3-C) reduced H/R-induced apoptosis as well as generation of reactive oxygen species (ROS) in hepatocytes. Interestingly, Stat3-C induced Mn-SOD, but not Cu/Zn-SOD, both at the protein and mRNA levels. Overexpression of Mn-SOD significantly reduced H/R-induced ROS and apoptosis by inhibiting redox-sensitive activation of caspase-3 activity. CONCLUSIONS: Stat3 protects hepatocytes from H/R-induced cell injury at least partly by upregulating Mn-SOD and inactivating caspase-3.

Comprehensive examination of gene expression associated with long-term stable graft acceptance by renal transplant recipients.

Expression levels of mRNA in peripheral blood mononuclear cells from five renal transplant recipients and five non-transplanted controls were analyzed with GeneChips (GeneChip Instrument system, Affymetrix, Santa Clara, CA, USA). All recipients had retained a well-functioning kidney graft for more than 15 yr on low-dose maintenance immunosuppression. Among a total of 12630 transcripts examined, significant differential expression was observed for 599 genes, whereby 470 genes were up-regulated and 129 down-regulated in the transplant recipients compared with controls. Of these, 192 up-regulated and 46 down-regulated genes showing a change greater than twofold were divided into eight functional categories as follows (numbers of genes, up/down): immune system (12/14), cell proliferation (17/3), oncology (15/3), transporter/receptor/binding protein (16/5), transcription factors (8/2), enzymes (17/4), expressed sequence tags (91/9), and others (16/6). Predictably, expression of immune-associated genes was decreased in the recipients. Significant reduction of expression levels of CD3, ICAM-1, and B7.2, which are critical molecules for interactions between antigen presenting cells and T cells, were observed. In T cell signal transduction, the Ras pathway was likely to be suppressed by activation of hVH-5. The present data help to elucidate the immunological status in long-term kidney graft recipients and may provide insights for future regimens to establish donor-specific hyporesponsiveness.

Stat3 protects against Fas-induced liver injury by redox-dependent and -independent mechanisms.

Signal transducer and activator of transcription-3 (Stat3) is one of the most important molecules involved in the initiation of liver development and regeneration. In order to investigate the hepatoprotective effects of Stat3, we examined whether Stat3 protects against Fas-mediated liver injury in the mouse. A constitutively activated form of Stat3 (Stat3-C) was adenovirally overexpressed in mouse liver by intravenous injection, and then a nonlethal dose of Fas agonist (Jo2) was injected intraperitoneally into the mouse (0.3 microg/g body wt). Stat3-C dramatically suppressed both apoptosis and necrosis induced by Jo2. In contrast, liver-specific Stat3-knockout mice failed to survive following Jo2 injection. Stat3-C upregulated expression of FLICE inhibitor protein (FLIP), Bcl-xL, and Bcl-2, and accordingly downregulated activities of FLICE and caspase-3 that were redox-independent. Interestingly, Stat3-C also upregulated the redox-associated protein redox factor-1 (Ref-1) and reduced apoptosis in liver following Jo2 injection by suppressing oxidative stress and redox-sensitive caspase-3 activity. These findings indicate that Stat3 activation protects against Fas-mediated liver injury by inhibiting caspase activities in redox-dependent and -independent mechanisms.