Copper incorporated biomaterial-based technologies for multifunctional wound repair.

The treatment of wounds is a worldwide challenge, and wound infection can affect the effectiveness of wound treatment and further increase the disease burden. Copper is an essential trace element that has been shown to have broad-spectrum antibacterial effects and to be involved in the inflammation, proliferation, and remodeling stages of wound healing. Compared to treatments such as bioactive factors and skin grafts, copper has the advantage of being low-cost and easily available, and has received a lot of attention in wound healing. Recently, biomaterials made by incorporating copper into bioactive glasses, polymeric scaffolds and hydrogels have been used to promote wound healing by the release of copper ions. In addition, copper-incorporated biomaterials with catalytic, photothermal, and photosensitive properties can also accelerate wound healing through antibacterial and wound microenvironment regulation. This review summarizes the antibacterial mechanisms of copper- incorporated biomaterials and their roles in wound healing, and discusses the current challenges. A comprehensive understanding of the role of copper in wounds will help to facilitate new preclinical and clinical studies, thus leading to the development of novel therapeutic tools.

Bone-Targeted Biomimetic Nanogels Re-Establish Osteoblast/Osteoclast Balance to Treat Postmenopausal Osteoporosis.

Insufficient bone formation and excessive bone resorption caused by estrogen deficiency are the major factors resulting in the incidence of postmenopausal osteoporosis (PMOP). The existing drugs usually fail to re-establish the osteoblast/osteoclast balance from both sides and generate side-effects owing to the lack of bone-targeting ability. Here, engineered cell-membrane-coated nanogels PNG@mR&C capable of scavenging receptor activator of nuclear factor-κB ligand (RANKL) and responsively releasing therapeutic PTH 1-34 in the bone microenvironment are prepared from RANK and CXCR4 overexpressed bone mesenchymal stem cell (BMSC) membrane-coated chitosan biopolymers. The CXCR4 on the coated-membranes confer bone-targeting ability, and abundant RANK effectively absorb RANKL to inhibit osteoclastogenesis. Meanwhile, the release of PTH 1-34 triggered by osteoclast-mediated acid microenvironment promote osteogenesis. In addition, the dose and frequency are greatly reduced due to the smart release property, prolonged circulation time, and bone-specific accumulation. Thus, PNG@mR&C exhibits satisfactory therapeutic effects in the ovariectomized (OVX) mouse model. This study provides a new paradigm re-establishing the bone metabolic homeostasis from multitargets and shows great promise for the treatment of PMOP.

Phototherapy techniques for the management of musculoskeletal disorders: strategies and recent advances.

Musculoskeletal disorders (MSDs), which include a range of pathologies affecting bones, cartilage, muscles, tendons, and ligaments, account for a significant portion of the global burden of disease. While pharmaceutical and surgical interventions represent conventional approaches for treating MSDs, their efficacy is constrained and frequently accompanied by adverse reactions. Considering the rising incidence of MSDs, there is an urgent demand for effective treatment modalities to alter the current landscape. Phototherapy, as a controllable and non-invasive technique, has been shown to directly regulate bone, cartilage, and muscle regeneration by modulating cellular behavior. Moreover, phototherapy presents controlled ablation of tumor cells, bacteria, and aberrantly activated inflammatory cells, demonstrating therapeutic potential in conditions such as bone tumors, bone infection, and arthritis. By constructing light-responsive nanosystems, controlled drug delivery can be achieved to enable precise treatment of MSDs. Notably, various phototherapy nanoplatforms with integrated imaging capabilities have been utilized for early diagnosis, guided therapy, and prognostic assessment of MSDs, further improving the management of these disorders. This review provides a comprehensive overview of the strategies and recent advances in the application of phototherapy for the treatment of MSDs, discusses the challenges and prospects of phototherapy, and aims to promote further research and application of phototherapy techniques.

Recent advances in carboxymethyl chitosan-based materials for biomedical applications.

Chitosan (CS) and its derivatives have been applied extensively in the biomedical field owing to advantageous characteristics including biodegradability, biocompatibility, antibacterial activity and adhesive properties. The low solubility of CS at physiological pH limits its use in systems requiring higher dissolving ability and a suitable drug release rate. Besides, CS can result in fast drug release because of its high swelling degree and rapid water absorption in aqueous media. As a water-soluble derivative of CS, carboxymethyl chitosan (CMC) has certain improved properties, rendering it a more suitable candidate for wound healing, drug delivery and tissue engineering applications. This review will focus on the antibacterial, anticancer and antitumor, antioxidant and antifungal bioactivities of CMC and the most recently described applications of CMC in wound healing, drug delivery, tissue engineering, bioimaging and cosmetics.

Lachnochromonin, a fungal metabolite from Lachnum virgineum, inhibits cell growth and promotes apoptosis in tumor cells through JAK/STAT3 signaling.

Natural compounds that interfere with tumor cell growth have potential to be used as therapeutic agents to treat cancers. Lachnochromonin (p71) is a small molecule isolated from Lachnum virgineum. Here, we reported the effect of p71 on human tumor cells, especially on breast cancer MCF-7 cells. We found that p71 significantly suppresses cell growth and induces apoptosis. The luciferase results demonstrated that p71 specifically attenuates the activation of JAK/STAT3 signaling. Biochemical analysis revealed that p71 blocks the phosphorylation of STAT3 tyrosine 705 and serine 727, resulting in down-regulation of c-Myc and Cyclin D1 expression level. Importantly, p71 inhibited cell growth, colony-formation, and migration through affecting STAT3 activity. These results implied that p71 may be used as a therapeutic agent against breast cancer.

A bone-targeted engineered exosome platform delivering siRNA to treat osteoporosis.

The complex pathogenesis of osteoporosis includes excessive bone resorption, insufficient bone formation and inadequate vascularization, a combination which is difficult to completely address with conventional therapies. Engineered exosomes carrying curative molecules show promise as alternative osteoporosis therapies, but depend on specifically-functionalized vesicles and appropriate engineering strategies. Here, we developed an exosome delivery system based on exosomes secreted by mesenchymal stem cells (MSCs) derived from human induced pluripotent stem cells (iPSCs). The engineered exosomes BT-Exo-siShn3, took advantage of the intrinsic anti-osteoporosis function of these special MSC-derived exosomes and collaborated with the loaded siRNA of the Shn3 gene to enhance the therapeutic effects. Modification of a bone-targeting peptide endowed the BT-Exo-siShn3 an ability to deliver siRNA to osteoblasts specifically. Silencing of the osteoblastic Shn3 gene enhanced osteogenic differentiation, decreased autologous RANKL expression and thereby inhibited osteoclast formation. Furthermore, Shn3 gene silencing increased production of SLIT3 and consequently facilitated vascularization, especially formation of type H vessels. Our study demonstrated that BT-Exo-siShn3 could serve as a promising therapy to kill three birds with one stone and implement comprehensive anti-osteoporosis effects.

Simple and versatile imaging of genomic loci in live mammalian cells and early pre-implantation embryos using CAS-LiveFISH.

Visualizing the 4D genome in live cells is essential for understanding its regulation. Programmable DNA-binding probes, such as fluorescent clustered regularly interspaced short palindromic repeats (CRISPR) and transcription activator-like effector (TALE) proteins have recently emerged as powerful tools for imaging specific genomic loci in live cells. However, many such systems rely on genetically-encoded components, often requiring multiple constructs that each must be separately optimized, thus limiting their use. Here we develop efficient and versatile systems, based on in vitro transcribed single-guide-RNAs (sgRNAs) and fluorescently-tagged recombinant, catalytically-inactivated Cas9 (dCas9) proteins. Controlled cell delivery of pre-assembled dCas9-sgRNA ribonucleoprotein (RNP) complexes enables robust genomic imaging in live cells and in early mouse embryos. We further demonstrate multiplex tagging of up to 3 genes, tracking detailed movements of chromatin segments and imaging spatial relationships between a distal enhancer and a target gene, with nanometer resolution in live cells. This simple and effective approach should facilitate visualizing chromatin dynamics and nuclear architecture in various living systems.

Sirt3-mediated mitophagy regulates AGEs-induced BMSCs senescence and senile osteoporosis.

Senile osteoporosis (SOP) is widely regarded as one of the typical aging-related diseases due to a decrease in bone mass and the destruction in microarchitecture. The inhibition of mitophagy can promote bone marrow mesenchymal stem cells (BMSCs) senescence, and increasing studies have shown that interventions targeting BMSCs senescence can ameliorate osteoporosis, exhibiting their potential for use as therapeutic strategies. Sirtuin-3 (Sirt3) is an essential mitochondria metabolic regulatory enzyme that plays an important role in mitochondrial homeostasis, but its role in bone homeostasis remains largely unknown. This study seeks to investigate whether advanced glycation end products (AGEs) accumulation aggravated BMSCs senescence and SOP, and explored the mechanisms underlying these effects. We observed that AGEs significantly aggravated BMSCs senescence, as well as promoted mitochondrial dysfunction and inhibited mitophagy in a concentration-dependent manner. In addition, this effect could be further strengthened by Sirt3 silencing. Importantly, we identified that the reduction of Sirt3 expression and the mitophagy were vital mechanisms in AGEs-induced BMSCs senescence. Furthermore, overexpression of Sirt3 by intravenously injection with recombinant adeno-associated virus 9 carrying Sirt3 plasmids (rAAV-Sirt3) significantly alleviated BMSCs senescence and the formation of SOP in SAMP6. In conclusion, our data demonstrated that Sirt3 protects against AGEs-induced BMSCs senescence and SOP. Targeting Sirt3 to improve mitophagy may represent a potential therapeutic strategy for attenuating AGEs-associated SOP.

Nuclear termination of STAT3 signaling through SIPAR (STAT3-Interacting Protein As a Repressor)-dependent recruitment of T cell tyrosine phosphatase TC-PTP.

STAT3 is associated with embryo development and survival as well as proliferation and metastasis of tumor cells. In a previous study, we demonstrated that STAT3-Interacting Protein As a Repressor (SIPAR) enhances the dephosphorylation of STAT3 and negatively regulates its activity. However, it remains unclear how SIPAR inhibits phosphorylation of STAT3. Here we demonstrate that SIPAR directly interacts with T cell protein tyrosine phosphatase TC45 and enhances its association with STAT3. This interaction triggers an accelerated dephosphorylation process for STAT3. Furthermore, SIPAR inhibits the transcriptional activity of STAT3 in wild-type MEF cells but not in TC45 null MEF cells. These results suggest that SIPAR terminates the activation of STAT3 through a dephosphorylation process that is dependent upon interaction with TC45 in the nucleus.

Insulin receptor substrate 1/2 (IRS1/2) regulates Wnt/ß-catenin signaling through blocking autophagic degradation of dishevelled2.

Wnt signaling plays a pivotal role in cell proliferation, tissue homeostasis, and tumorigenesis. Dishevelled (Dvl) is a central node of Wnt signaling. Insulin receptor substrates (IRSs), as a critical component of insulin signaling, are involved in cell proliferation, metabolism, and cancer development. In this study, we report that IRS1/2 promotes Wnt/ß-catenin signaling by stabilizing Dvl2. We found that IRS1/2 interacts with Dvl2. Overexpression of IRS1/2 increased the protein level of Dvl2 and promoted canonical Wnt signaling, as evidenced by the increased T cell-specific factor 4 transcriptional activity and the up-regulation of expression of CYCLIN D1 and c-MYC, two Wnt target genes critical for cell growth, whereas depletion of IRS1/2 reduced the level of Dvl2 and attenuated Wnt/ß-catenin signaling. Biochemical analyses revealed that IRS1/2 decreased Lys-63-linked ubiquitination of Dvl2 and stabilized Dvl2 protein via suppressing its autophagy-mediated degradation. We further revealed that IRS1/2 blocks autophagy-induced formation of the Dvl2-p62/SQSTM1 complex, resulting in disabled association of Dvl2 to autophagosomes. We demonstrated that IRS1/2 promoted the induction of epithelial-mesenchymal transition (EMT) and cell proliferation in response to Wnt stimulation, whereas depletion of Dvl2 impaired the IRS1/2-mediated EMT and cell growth. Our findings revealed that IRS1/2 promotes EMT and cell proliferation through stabilizing Dvl2.

SIPAR negatively regulates STAT3 signaling and inhibits progression of melanoma.

Persistently activated STAT3 is important for tumorigenesis in a variety of cancers, including melanoma. Although many co-factors in the regulation of STAT3 activity have been identified, it remains unclear how STAT3 phosphorylation is negatively regulated. Here, we report that SIPAR (STAT3-Interacting Protein As a Repressor) inhibits STAT3 activity by accelerating its dephosphorylation. We observed that SIPAR directly interacted with STAT3 upon IL-6 stimulation. Moreover, over-expression of SIPAR reduced, whereas depletion enhanced, the level of phosphorylated STAT3. We further demonstrated that SIPAR inhibited the growth of melanoma cells by decreasing the level of phosphorylated STAT3 and the expression of its target genes. These results suggest that SIPAR, functioning as a new negative regulator, inhibits STAT3 activity by enhancing its dephosphorylation and represses melanoma progression.

Protein tyrosine phosphatase Meg2 dephosphorylates signal transducer and activator of transcription 3 and suppresses tumor growth in breast cancer.

INTRODUCTION: Signal transducer and activator of transcription 3 (STAT3) is over-activated or phosphorylated in breast cancers. The hyper-phosphorylation of STAT3 was attributed to either up-regulated phosphorylation by several tyrosine-kinases or down-regulated activity of phosphatases. Although several factors have been identified to phosphorylate STAT3, it remains unclear how STAT3 is dephosphorylated by PTPMeg2. The aim of this study was to determine the role of PTPMeg2 as a phosphatase in regulation of the activity of STAT3 in breast cancers. METHODS: Immunoprecipitation assays were used to study the interaction of STAT3 with PTPMeg2. A series of biochemistry experiments were performed to evaluate the role of PTPMeg2 in the dephosphorylation of STAT3. Two breast cancer cell lines MCF7 (PTPMeg2 was depleted as it was endogenously high) and MDA-MB-231 (PTPMeg2 was overexpressed as it was endogenously low) were used to compare the level of phosphorylated STAT3 and the tumor growth ability in vitro and in vivo. Samples from breast carcinoma (n = 73) were subjected to a pair-wise Pearson correlation analysis for the correlation of levels of PTPMeg2 and phosphorylated STAT3. RESULTS: PTPMeg2 directly interacts with STAT3 and mediates its dephosphorylation in the cytoplasm. Over-expression of PTPMeg2 decreased tyrosine phosphorylation of STAT3 while depletion of PTPMeg2 increased its phosphorylation. The decreased tyrosine phosphorylation of STAT3 is coupled with suppression of STAT3 transcriptional activity and reduced tumor growth in vitro and in vivo. Levels of PTPMeg2 and phosphorylated STAT3 were inversely correlated in breast cancer tissues (P = 0.004). CONCLUSIONS: PTPMeg2 is an important phosphatase for the dephosphorylation of STAT3 and plays a critical role in breast cancer development.

Transmission line based short pulse generation circuits in a 0.13 µm complementary metal-oxide-semiconductor technology.

A few traditional pulse forming circuits are implemented and compared in a commercial 0.13 µm digital CMOS technology. Standard on-chip transmission lines are used as pulse forming lines (PFLs), while CMOS transistors are used as switches. The shortest output pulses of these circuits are analyzed and compared through Cadence Spectre simulations. All the CMOS circuits are fabricated in the commercial technology. Pulses of ∼170 ps durations and 120-400 mV amplitudes are obtained when the power supply is tuned from 1.2 to 2 V. The results show that these traditional PFL based circuits can be implemented in standard CMOS technology for high power short pulse generations. Furthermore, the PFL circuits significantly extend the short pulse generation capabilities of CMOS technologies.