PD-L1 in melanoma and extracellular vesicles promotes local and regional immune suppression through M2-like macrophage polarization.

Tumor-associated macrophages (TAMs) exhibit dual roles in tumor progression. TAMs are known to induce PD-L1 expression in cancer cells. However, the regulatory effects of PD-L1 in melanoma cells on TAM phenotypical switching remain underexplored. Herein, our findings indicated that CD163 and MRC1 levels were significantly elevated in metastatic melanomas compared to primary melanomas, correlating with CD274 expression and predicted patient clinical outcomes. To study the mechanisms regulating M2-like polarization, PD-L1 was knocked out in both YUMM1.7 and B16-F10 melanoma cells. The data revealed that knocking out PD-L1 (PD-L1KO) in melanoma resulted in a decelerated in vivo growth rate, accompanied by a significantly increased M1/M2 ratio, more dendritic cells, and enhanced activation of CD8+ T cells compared to wild-type (WT) melanoma cells. These alterations were associated with decreased expression of M2-associated chemokines (CCL2, CCL3, and CXCL2) and cytokines (IL6, IL10, and TGFß1). Mice harboring PD-L1KO melanomas exhibited elevated levels of CD8+ T cells in both the tumor-draining lymph nodes and the bloodstream, compared to mice with PD-L1WT melanomas. Treatment with extracellular vesicles (EVs) derived from PD-L1KO melanoma resulted in a reduced tumor growth rate and fewer M2-like macrophages in the tumors compared to EVs from PD-L1WT melanomas. Therefore, our data suggest that PD-L1 in melanoma and melanoma-derived EVs induces M2-like polarization, contributing to local and regional immune suppression.

Unveiling Therapeutic Opportunities with Melanoma Patient-derived Organoid Models.

With the development of immunotherapy, there is an ongoing need to develop models that can recapitulate the tumor microenvironment of native tumors. While traditional two- and three-dimensional models can offer insights into cancer development and progression, these lack crucial aspects that hinder a faithful mimic of native tumors. An alternative model that has gained a lot of attention is the patient-derived organoid. The development of these organoids recapitulates the complex intercellular communication, tumor microenvironment, and histoarchitecture of tumors. This paper describes the protocol for establishing melanoma patient-derived organoid (MPDO) models. To validate these models, we assessed the immune cell composition, including the expression levels of T-cell activation markers, to confirm the cellular heterogeneity of the organoids. Additionally, to describe the potential utility of MPDOs in cellular therapies, we evaluated the cytotoxic capabilities of treating the organoids with γδ T-cells. In conclusion, the MPDO models offer promising avenues for understanding tumor complexity, validating therapeutic strategies, and potentially advancing personalized treatment.

Novel Carbon Quantum Dots Precisely Trigger Ferroptosis in Cancer Cells through Antioxidant Inhibition Synergistic Nanocatalytic Activity.

High levels of glutathione (GSH) are an important characteristic of malignant tumors and a significant cause of ineffective treatment and multidrug resistance. Although reactive oxygen species (ROS) therapy has been shown to induce tumor cell death, the strong clearance effect of GSH on ROS significantly reduces its therapeutic efficacy. Therefore, there is a need to develop new strategies for targeting GSH. In this study, novel carbon quantum dots derived from gentamycin (GM-CQDs) were designed and synthesized. On the basis of the results obtained, GM-CQDs contain sp2 and sp3 carbon atoms as well as nitrogen oxygen groups, which decrease the intracellular levels of GSH by downregulating SLC7A11, thereby disrupting redox balance, mediating lipid peroxidation, and inducing ferroptosis. Transcriptome analysis demonstrated that GM-CQDs downregulated the expression of molecules related to GSH metabolism while significantly increasing the expression of molecules related to ferroptosis. The in vivo results showed that the GM-CQDs exhibited excellent antitumor activity and immune activation ability. Furthermore, because of their ideal biological safety, GM-CQDs are highly promising for application as drugs targeting GSH in the treatment of malignant tumors.

TCL1A-expressing B cells are critical for tertiary lymphoid structure formation and the prognosis of oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a malignant tumor with a poor prognosis. Traditional treatments have limited effectiveness. Regulation of the immune response represents a promising new approach for OSCC treatment. B cells are among the most abundant immune cells in OSCC. However, the role of B cells in OSCC treatment has not been fully elucidated. METHODS: Single-cell RNA sequencing analysis of 13 tissues and 8 adjacent normal tissues from OSCC patients was performed to explore differences in B-cell gene expression between OSCC tissues and normal tissues. We further investigated the relationship between differentially expressed genes and the immune response to OSCC. We utilized tissue microarray data for 146 OSCC clinical samples and RNA sequencing data of 359 OSCC samples from The Cancer Genome Atlas (TCGA) to investigate the role of T-cell leukemia 1 A (TCL1A) in OSCC prognosis. Multiplex immunohistochemistry (mIHC) was employed to investigate the spatial distribution of TCL1A in OSCC tissues. We then investigated the effect of TCL1A on B-cell proliferation and trogocytosis. Finally, lentiviral transduction was performed to induce TCL1A overexpression in B lymphoblastoid cell lines (BLCLs) to verify the function of TCL1A. RESULTS: Our findings revealed that TCL1A was predominantly expressed in B cells and was associated with a better prognosis in OSCC patients. Additionally, we found that TCL1A-expressing B cells are located at the periphery of lymphatic follicles and are associated with tertiary lymphoid structures (TLS) formation in OSCC. Mechanistically, upregulation of TCL1A promoted the trogocytosis of B cells on dendritic cells by mediating the upregulation of CR2, thereby improving antigen-presenting ability. Moreover, the upregulation of TCL1A expression promoted the proliferation of B cells. CONCLUSION: This study revealed the role of B-cell TCL1A expression in TLS formation and its effect on OSCC prognosis. These findings highlight TCL1A as a novel target for OSCC immunotherapy.

Graphene-Based Material-Mediated Immunomodulation in Tissue Engineering and Regeneration: Mechanism and Significance.

Tissue engineering and regenerative medicine hold promise for improving or even restoring the function of damaged organs. Graphene-based materials (GBMs) have become a key player in biomaterials applied to tissue engineering and regenerative medicine. A series of cellular and molecular events, which affect the outcome of tissue regeneration, occur after GBMs are implanted into the body. The immunomodulatory function of GBMs is considered to be a key factor influencing tissue regeneration. This review introduces the applications of GBMs in bone, neural, skin, and cardiovascular tissue engineering, emphasizing that the immunomodulatory functions of GBMs significantly improve tissue regeneration. This review focuses on summarizing and discussing the mechanisms by which GBMs mediate the sequential regulation of the innate immune cell inflammatory response. During the process of tissue healing, multiple immune responses, such as the inflammatory response, foreign body reaction, tissue fibrosis, and biodegradation of GBMs, are interrelated and influential. We discuss the regulation of these immune responses by GBMs, as well as the immune cells and related immunomodulatory mechanisms involved. Finally, we summarize the limitations in the immunomodulatory strategies of GBMs and ideas for optimizing GBM applications in tissue engineering. This review demonstrates the significance and related mechanism of the immunomodulatory function of GBM application in tissue engineering; more importantly, it contributes insights into the design of GBMs to enhance wound healing and tissue regeneration in tissue engineering.

Erratum: Functionalization of SF/HAP Scaffold with GO-PEI-miRNA inhibitor Complexes to Enhance Bone Regeneration through Activating Transcription Factor 4: Erratum.

[This corrects the article DOI: 10.7150/thno.34676.].

Patient-derived melanoma organoid models facilitate the assessment of immunotherapies.

BACKGROUND: Only a minority of melanoma patients experience durable responses to immunotherapies due to inter- and intra-tumoral heterogeneity in melanoma. As a result, there is a pressing need for suitable preclinical models to investigate resistance mechanisms and enhance treatment efficacy. METHODS: Here, we report two different methods for generating melanoma patient-derived organoids (MPDOs), one is embedded in collagen gel, and the other is inlaid in Matrigel. MPDOs in Matrigel are used for assessing the therapeutic effects of anti-PD-1 antibodies (αPD-1), autochthonous tumor infiltrating lymphocytes (TILs), and small molecule compounds. MPDOs in collagen gel are used for evaluating the chemotaxis and migratory capacity of TILs. FINDING: The MPDOs in collagen gel and Matrigel have similar morphology and immune cell composition to their parental melanoma tissues. MPDOs show inter- and intra-tumoral heterogeneity and contain diverse immune cells such as CD4+, CD8+ T, Treg, CD14+ monocytic, CD15+, and CD11b+ myeloid cells. The tumor microenvironment (TME) in MPDOs is highly immunosuppressive, and the lymphoid and myeloid lineages express similar levels of PD-1, PD-L1, and CTLA-4 as their parental melanoma tissues. Anti-PD-1 antibodies (αPD-1) reinvigorate CD8+ T cells and induce melanoma cell death in the MPDOs. TILs expanded by IL-2 and αPD-1 show significantly lower expression of TIM-3, better migratory capacity and infiltration of autochthonous MPDOs, and more effective killing of melanoma cells than TILs expanded by IL-2 alone or IL-2 with αCD3. A small molecule screen discovers that Navitoclax increases the cytotoxicity of TIL therapy. INTERPRETATION: MPDOs may be used to test immune checkpoint inhibitors and cellular and targeted therapies. FUNDING: This work was supported by the NIH grants CA114046, CA261608, CA258113, and the Tara Miller Melanoma Foundation.

The construction and analysis of tricarboxylic acid cycle related prognostic model for cervical cancer.

Introduction: Cervical cancer (CC) is the fourth most common malignant tumor in term of in incidence and mortality among women worldwide. The tricarboxylic acid (TCA) cycle is an important hub of energy metabolism, networking one-carbon metabolism, fatty acyl metabolism and glycolysis. It can be seen that the reprogramming of cell metabolism including TCA cycle plays an indispensable role in tumorigenesis and development. We aimed to identify genes related to the TCA cycle as prognostic markers in CC. Methods: Firstly, we performed the differential expressed analysis the gene expression profiles associated with TCA cycle obtained from The Cancer Genome Atlas (TCGA) database. Differential gene list was generated and cluster analysis was performed using genes with detected fold changes >1.5. Based on the subclusters of CC, we analysed the relationship between different clusters and clinical information. Next, Cox univariate and multivariate regression analysis were used to screen genes with prognostic characteristics, and risk scores were calculated according to the genes with prognostic characteristics. Additionally, we analyzed the correlation between the predictive signature and the treatment response of CC patients. Finally, we detected the expression of ench prognostic gene in clinical CC samples by quantitative polymerase chain reaction (RT-qPCR). Results: We constructed a prognostic model consist of seven TCA cycle associated gene (ACSL1, ALDOA, FOXK2, GPI, MDH1B, MDH2, and MTHFD1). Patients with CC were separated into two groups according to median risk score, and high-risk group had a worse prognosis compared to the low-risk group. High risk group had lower level of sensitivity to the conventional chemotherapy drugs including cisplatin, paclitaxel, sunitinib and docetaxel. The expression of ench prognostic signature in clinical CC samples was verified by qRT-PCR. Conclusion: There are several differentially expressed genes (DEGs) related to TCA cycle in CC. The risk score model based on these genes can effectively predict the prognosis of patients and provide tumor markers for predicting the prognosis of CC.

Preclinical platforms to study therapeutic efficacy of human γδ T cells.

BACKGROUND: Gamma delta (γδ) T lymphocytes are promising candidate for adoptive T cell therapy, however, their treatment efficacy is not satisfactory. Vδ2 T cells are unique to primates and few suitable models are available to assay their anti-tumour function. METHODS: We tested human γδ T cell activation, tumour infiltration, and tumour-killing in four three-dimensional (3D) models, including unicellular, bicellular and multicellular melanoma spheroids, and patient-derived melanoma organoids. We studied the effects of checkpoint inhibitors on γδ T cells and performed a small molecule screen using these platforms. RESULTS: γδ T cells rapidly responded to melanoma cells and infiltrated melanoma spheroids better than αß T cells in PBMCs. Cancer-associated fibroblasts (CAFs) in bicellular spheroids, stroma cells in multicellular melanoma spheroids and inhibitory immune cells in organoids significantly inhibited immune cell infiltrates including γδ T cells and lessened their cytotoxicity to tumour cells. Tumour-infiltrating γδ T cells showed exhausted immunophenotypes with high checkpoints expression (CTLA-4, PD-1 and PD-L1). Immune checkpoint inhibitors increased γδ T cell infiltration of 3D models and killing of melanoma cells in all four 3D models. Our small molecule screen assay and subsequent mechanistic studies demonstrated that epigenetic modifiers enhanced the chemotaxis and cytotoxicity of γδ T cells through upregulating MICA/B, inhibiting HDAC6/7 pathway and downregulating the levels of PD-L1 and PD-L2 in CAFs and tumour cells. These compounds increased CXCR4 and CD107a expression, IFN-γ production and decreased PD-1 expression of γδ T cells. CONCLUSIONS: Tumour-infiltrating γδ T cells show exhausted immunophenotypes and limited anti-tumour capacity in melanoma 3D models. Checkpoint inhibitors and epigenetic modifiers enhance anti-tumour functions of γδ T cells. These four 3D models provided valuable preclinical platforms to test γδ T cell functions for immunotherapy.

Costimulation of γδTCR and TLR7/8 promotes Vδ2 T-cell antitumor activity by modulating mTOR pathway and APC function.

BACKGROUND: Gamma delta (γδ) T cells are attractive effector cells for cancer immunotherapy. Vδ2 T cells expanded by zoledronic acid (ZOL) are the most commonly used γδ T cells for adoptive cell therapy. However, adoptive transfer of the expanded Vδ2 T cells has limited clinical efficacy. METHODS: We developed a costimulation method for expansion of Vδ2 T cells in PBMCs by activating γδ T-cell receptor (γδTCR) and Toll-like receptor (TLR) 7/8 using isopentenyl pyrophosphate (IPP) and resiquimod, respectively, and tested the functional markers and antitumoral effects in vitro two-dimensional two-dimensional and three-dimensional spheroid models and in vivo models. Single-cell sequencing dataset analysis and reverse-phase protein array were employed for mechanistic studies. RESULTS: We find that Vδ2 T cells expanded by IPP plus resiquimod showed significantly increased cytotoxicity to tumor cells with lower programmed cell death protein 1 (PD-1) expression than Vδ2 T cells expanded by IPP or ZOL. Mechanistically, the costimulation enhanced the activation of the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB/Akt)-the mammalian target of rapamycin (mTOR) pathway and the TLR7/8-MyD88 pathway. Resiquimod stimulated Vδ2 T-cell expansion in both antigen presenting cell dependent and independent manners. In addition, resiquimod decreased the number of adherent inhibitory antigen-presenting cells (APCs) and suppressed the inhibitory function of APCs by decreasing PD-L1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression in these cells during in vitro Vδ2 T-cell expansion. Finally, we showed that human Vδ2 T cells can be expanded from PBMCs and spleen of humanized NSG mice using IPP plus resiquimod or ZOL, demonstrating that humanized mice are a promising preclinical model for studying human γδ T-cell development and function. CONCLUSIONS: Vδ2 T cells expanded by IPP and resiquimod demonstrate improved anti-tumor function and have the potential to increase the efficacy of γδ T cell-based therapies.

Targeting regulatory T cells for immunotherapy in melanoma.

Regulatory T cells (Tregs) are essential in the maintenance of immunity, and they are also a key to immune suppressive microenvironment in solid tumors. Many studies have revealed the biology of Tregs in various human pathologies. Here we review recent understandings of the immunophenotypes and suppressive functions of Tregs in melanoma, including Treg recruitment and expansion in a tumor. Tregs are frequently accumulated in melanoma and the ratio of CD8+ T cells versus Tregs in the melanoma is predictive for patient survival. Hence, depletion of Tregs is a promising strategy for the enhancement of anti-melanoma immunity. Many recent studies are aimed to target Tregs in melanoma. Distinguishing Tregs from other immune cells and understanding the function of different subsets of Tregs may contribute to better therapeutic efficacy. Depletion of functional Tregs from the tumor microenvironment has been tested to induce clinically relevant immune responses against melanomas. However, the lack of Treg specific therapeutic antibodies or Treg specific depleting strategies is a big hurdle that is yet to be overcome. Additional studies to fine-tune currently available therapies and more agents that specifically and selectively target tumor infiltrating Tregs in melanoma are urgently needed.

Small extracellular vesicles-based cell-free strategies for therapy.

Small extracellular vesicles (sEVs) are extracellular nanovesicles that contain bioactive proteins, lipids, RNA, and DNA. A variety of biological process is regulated with sEVs. sEVs are an intercellular messenger regulating recipient cell function and play a role in disease initiation and progression. sEVs derived from certain cells, such as mesenchymal stem cells and immune cells, have the potential for clinical therapy as they possess the characteristics of their parental cells. With better understanding of sEVs biogenesis, their transportation properties, extended circulatory capability, and exceptional biocompatibility, sEVs emerge as a potential therapeutic tool in the clinic. Here, we summarize applications of sEVs-based therapies in different diseases and current knowledge about the strategies in bioengineered sEVs, as well as the challenges for their use in clinical settings.

Dichotomous and stable gamma delta T-cell number and function in healthy individuals.

BACKGROUND: Gamma-delta (γδ) T lymphocytes are primed to potently respond to pathogens and transformed cells by recognizing a broad range of antigens. However, adoptive immunotherapy with γδT cells has exhibited mixed treatment responses. Better understanding of γδT cell biology and stratifying healthy donors for allogeneic adoptive therapy is clinically needed to fully realize the therapeutic potential of γδT cells. METHODS: We examine 98 blood samples from healthy donors and measure their expansion capacity after zoledronate stimulation, and test the migration and cytotoxic effector function of expanded γδT cells in 2D culture, 3D tumor spheroid and patient-derived melanoma organoid assays. RESULTS: We find that γδT cell expansion capacity is independent of expansion methods, gender, age and HLA type. Basal γδT cell levels in Peripheral blood mononuclear cell (PBMC) correlate well with their expansion, migration and cytotoxic effector capacity in vitro. Circulating γδT cells with lower expression of PD-1, CTLA-4, Eomes, T-bet and CD69, or higher IFN-γ production expand better. γδT cells with central memory and effector memory phenotypes are significantly more abundant in good expanders. A cut-off level of 0.82% γδT cells in PBMC stratifies good versus poor γδT cell expansion with a sensitivity of 97.78%, specificity of 90.48% and area under the curve of 0.968 in a healthy individual. Donors with higher Vδ2 Index Score in PBMC have greater anti-tumor functions including migratory function and cytotoxicity. CONCLUSIONS: Our results demonstrate that the interindividual γδT cell functions correlate with their circulating levels in healthy donors. Examination of circulating γδT cell level may be used to select healthy donors to participate in γδT-based immunotherapies.

Nanomaterials and hepatic disease: toxicokinetics, disease types, intrinsic mechanisms, liver susceptibility, and influencing factors.

The widespread use of nanomaterials (NMs) has raised concerns that exposure to them may introduce potential risks to the human body and environment. The liver is the main target organ for NMs. Hepatotoxic effects caused by NMs have been observed in recent studies but have not been linked to liver disease, and the intrinsic mechanisms are poorly elucidated. Additionally, NMs exhibit varied toxicokinetics and induce enhanced toxic effects in susceptible livers; however, thus far, this issue has not been thoroughly reviewed. This review provides an overview of the toxicokinetics of NMs. We highlight the possibility that NMs induce hepatic diseases, including nonalcoholic steatohepatitis (NASH), fibrosis, liver cancer, and metabolic disorders, and explore the underlying intrinsic mechanisms. Additionally, NM toxicokinetics and the potential induced risks in the livers of susceptible individuals, including subjects with liver disease, obese individuals, aging individuals and individuals of both sexes, are summarized. To understand how NM type affect their toxicity, the influences of the physicochemical and morphological (PCM) properties of NMs on their toxicokinetics and toxicity are also explored. This review provides guidance for further toxicological studies on NMs and will be important for the further development of NMs for applications in various fields.

Efficient miRNA Inhibitor with GO-PEI Nanosheets for Osteosarcoma Suppression by Targeting PTEN.

BACKGROUND: Gene therapy is considered a novel way to treat osteosarcoma, and microRNAs are potential therapeutic targets for osteosarcoma. miR-214 has been found to promote osteosarcoma aggression and metastasis. Graphene oxide (GO) is widely used for gene delivery for the distinct physiochemical properties and minimal cytotoxicity. METHODS: Polyethyleneimine (PEI)-functionalized GO complex was well-prepared and loaded with miR-214 inhibitor at different concentrations. The load efficacy was tested by gel retardation assay and the cy3-labeled fluorescence of cellular uptake. The experiments of wound healing, immunofluorescence staining, Western blot, qRT-PCR and immunohistochemical staining were performed to measure the inhibitory effect of the miR-214 inhibitor systematically released from the complexes against MG63, U2OS cells and xenograft tumors. RESULTS: The systematic mechanistic elucidation of the efficient delivery of the miR-214 inhibitor by GO-PEI indicated that the inhibition of cellular miR-214 caused a decrease in osteosarcoma cell invasion and migration and an increase in apoptosis by targeting phosphatase and tensin homolog (PTEN). The synergistic combination of the GO-PEI-miR-214 inhibitor and CDDP chemotherapy showed significant cell death. In a xenograft mouse model, the GO-PEI-miR-214 inhibitor significantly inhibited tumor volume growth. CONCLUSION: This study indicates the potential of functionalized GO-PEI as a vehicle for miRNA inhibitor delivery to treat osteosarcoma with low toxicity and miR-214 can be a good target for osteosarcoma therapy.

Efficient miRNA Inhibitor Delivery with Graphene Oxide-Polyethylenimine to Inhibit Oral Squamous Cell Carcinoma.

BACKGROUND: MicroRNAs (miRNAs) are widely believed to be promising targets for oral squamous cell carcinoma (OSCC) gene therapy. miR-214 has been identified as a promoter of OSCC aggression and metastasis. METHODS: Graphene oxide-polyethylenimine (GO-PEI) complexes were prepared and loaded with a miRNA inhibitor at different N/P ratios. The transfection efficiency of GO-PEI-inhibitor was tested in Cal27 and SCC9 cells. Moreover, the tumor inhibition ability of GO-PEI-inhibitor was measured in an OSCC xenograft mouse model by intratumoral injection. RESULTS: Here, we show that a GO-PEI complex efficiently delivers a miR-214 inhibitor into OSCC cells and controls the intracellular release of the miR-214 inhibitor. These results indicate that the GO-PEI-miR-214 inhibitor complex efficiently inhibited cellular miR-214, resulting in a decrease in OSCC cell invasion and migration and an increase in cell apoptosis by targeting PTEN and p53. In the xenograft mouse model, the GO-PEI-miR-214 inhibitor complex significantly prevented tumor volume growth. CONCLUSION: This study indicates that functionalized GO-PEI with low toxicity has promising potential for miRNA delivery for the treatment of OSCC.

Sialylation of FGFR1 by ST6Gal­I overexpression contributes to ovarian cancer cell migration and chemoresistance.

Fibroblast growth factor receptors (FGFRs) have been implicated in the malignant transformation and chemoresistance of epithelial ovarian cancer; however, the underlying molecular mechanisms are poorly understood. Increased sialyltransferase activity that enhances protein sialylation is an important post­translational process promoting cancer progression and malignancy. In the present study, α2,6­sialyltransferase (ST6Gal­I) overexpression or knockdown cell lines were developed, and FGFR1 was examined to understand the effect of sialylation on migration and drug resistance, and the underlying mechanisms. It was identified that cells with ST6Gal­I overexpression had increased cell viability and migratory ability upon serum deprivation. Moreover, ST6Gal­I overexpression cells had strong resistance to paclitaxel, as demonstrated by low growth inhibition rate and cell apoptosis level. A mechanistic study showed that ST6Gal­I overexpression induced high α2,6­sialylation of FGFR1 and increased the expression of phospho­ERK1/2 and phospho­focal adhesion kinase. Further study demonstrated that the FGFR1 inhibitor PD173047 reduced cell viability and induced apoptosis; however, ST6Gal­I overexpression decreased the anticancer effect of PD173047. In addition, ST6Gal­I overexpression attenuated the effect of Adriamycin on cancer cells. Collectively, these results suggested that FGFR1 sialylation plays an important role in cell migration and drug chemoresistance in ovarian cancer cells.

Functionalization of SF/HAP Scaffold with GO-PEI-miRNA inhibitor Complexes to Enhance Bone Regeneration through Activating Transcription Factor 4.

Evidence indicates that microRNAs (miRNAs) play vital roles in regulating osteogenic differentiation and bone formation. Methods: Here, we show that a polyethyleneimine (PEI)-functionalized graphene oxide (GO) complex efficiently loaded with the miR-214 inhibitor is assembled into silk fibroin/hydroxyapatite (SF/HAP) scaffolds that spatially control the release of the miR-214 inhibitor. Results: SF/HAP/GO scaffolds with nanosized GO show high mechanical strength, and their hierarchical microporous structures promote cell adhesion and growth. The SF/HAP/GO-PEI scaffolds loaded with mir-214 inhibitor (SF/HAP/GPM) were tested for their ability to enhance osteogenic differentiation by inhibiting the expression of miR-214 while inversely increasing the expression of activating transcription factor 4 (ATF4) and activating the Akt and ERK1/2 signaling pathways in mouse osteoblastic cells (MC3T3-E1) in vitro. Similarly, the scaffolds activated the osteoblastic activity of endogenous osteoblast cells to repair critical-sized bone defects in rats without the need for loading osteoblast cells. Conclusion: This technology is used to increase osteogenic differentiation and mineralized bone formation in bone defects, which helps to achieve cell-free scaffold-based miRNA-inhibitor therapy for bone tissue engineering.

A microRNA­24­to­secretagogin regulatory pathway mediates cholesterol­induced inhibition of insulin secretion.

Hypercholesterolemia is a key factor leading to ß­cell dysfunction, but its underlying mechanisms remain unclear. Secretagogin (Scgn), a Ca2+ sensor protein that is expressed at high levels in the islets, has been shown to play a key role in regulating insulin secretion through effects on the soluble N­ethylmaleimide­sensitive factor attachment receptor protein complexes. However, further studies are required to determine whether Scgn plays a role in hypercholesterolemia­associated ß­cell dysfunction. The present study investigated the involvement of a microRNA­24 (miR­24)­to­Scgn regulatory pathway in cholesterol­induced ß­cell dysfunction. In the present study, MIN6 cells were treated with increasing concentrations of cholesterol and then, the cellular functions and changes in the miR­24­to­Scgn signal pathway were observed. Excessive uptake of cholesterol in MIN6 cells increased the expression of miR­24, resulting in a reduction in Sp1 expression by directly targeting its 3' untranslated region. As a transcriptional activator of Scgn, downregulation of Sp1 decreased Scgn levels and subsequently decreased the phosphorylation of focal adhesion kinase and paxillin, which is regulated by Scgn. Therefore, the focal adhesions in insulin granules were impaired and insulin exocytosis was reduced. The present study concluded that a miR­24­to­Scgn pathway participates in the mechanism regulating cholesterol accumulation­induced ß­cell dysfunction.