Sodium phenylbutyrate inhibits Schwann cell inflammation via HDAC and NFκB to promote axonal regeneration and remyelination.

BACKGROUND: Epigenetic regulation by histone deacetylases (HDACs) in Schwann cells (SCs) after injury facilitates them to undergo de- and redifferentiation processes necessary to support various stages of nerve repair. Although de-differentiation activates the synthesis and secretion of inflammatory cytokines by SCs to initiate an immune response during nerve repair, changes in either the timing or duration of prolonged inflammation mediated by SCs can affect later processes associated with repair and regeneration. Limited studies have investigated the regulatory processes through which HDACs in SCs control inflammatory cytokines to provide a favorable environment for peripheral nerve regeneration. METHODS: We employed the HDAC inhibitor (HDACi) sodium phenylbutyrate (PBA) to address this question in an in vitro RT4 SC inflammation model and an in vivo sciatic nerve transection injury model to examine the effects of HDAC inhibition on the expression of pro-inflammatory cytokines. Furthermore, we assessed the outcomes of suppression of extended inflammation on the regenerative potential of nerves by assessing axonal regeneration, remyelination, and reinnervation. RESULTS: Significant reductions in lipopolysaccharide (LPS)-induced pro-inflammatory cytokine (tumor necrosis factor-α [TNFα]) expression and secretion were observed in vitro following PBA treatment. PBA treatment also affected the transient changes in nuclear factor κB (NFκB)-p65 phosphorylation and translocation in response to LPS induction in RT4 SCs. Similarly, PBA mediated long-term suppressive effects on HDAC3 expression and activity. PBA administration resulted in marked inhibition of pro-inflammatory cytokine secretion at the site of transection injury when compared with that in the hydrogel control group at 6-week post-injury. A conducive microenvironment for axonal regrowth and remyelination was generated by increasing expression levels of protein gene product 9.5 (PGP9.5) and myelin basic protein (MBP) in regenerating nerve tissues. PBA administration increased the relative gastrocnemius muscle weight percentage and maintained the intactness of muscle bundles when compared with those in the hydrogel control group. CONCLUSIONS: Suppressing the lengthened state of inflammation using PBA treatment favors axonal regrowth and remyelination following nerve transection injury. PBA treatment also regulates pro-inflammatory cytokine expression by inhibiting the transcriptional activation of NFκB-p65 and HDAC3 in SCs in vitro.

Reduction in MicroRNA-4488 Expression Induces NFκB Translocation in Venous Endothelial Cells Under Arterial Flow.

PURPOSE: Little is known about the molecular interactions among inflammatory responses that damage venous endothelial cells (vECs) during venous-to-arterial flow transition in vein graft diseases. Because arterial flow triggers excessive autophagy and inflammation in vECs, this study aimed to investigate the mediator of inflammation and methods to prevent vEC damage. METHODS: Arterial laminar shear stress (ALSS; 12 dynes/cm2) was applied to vECs via in vitro and ex vivo perfusion systems. Inflammation in vECs was measured using inflammatory protein markers, NFκB translocation, cyclooxygenase-2 (COX-2) and COX-2 and NFκB promoter assays. The involvement of microRNA-4488 (miR-4488) was measured and confirmed by altering the specific miR using a miR-4488 mimic or inhibitor. The potential anti-inflammatory drugs and/or nitric oxide (NO) donor L-arginine (L-Arg) to prevent damage to vECs under ALSS was investigated. RESULTS: ALSS triggered reactive oxygen species production, excessive autophagy, COX-2 protein expression, and NFκB translocation during vEC inflammation. Reduction in miR-4488 expression was detected in inflamed vECs treated with LPS, lipopolysaccharide (LPS) TNFα, and ALSS. Transfection of miR-4488 mimic (50 nM) prior to ALSS application inhibited the accumulation of inflammatory proteins as well as the translocation of NFκB. Combined treatment of vECs with COX-2-specific inhibitor (SC-236) and L-Arg alleviated the ALSS-induced inflammatory responses. Protective effects of the combined treatment on vECs against ALSS-induced damage were abolished by the application of miR-4488 inhibitor. CONCLUSION: We showed that ALSS triggered the COX-2/NFκB pathway to induce vEC inflammation with a reduction in miR-4488. Combination of SC-236 and L-Arg prevented ALSS-induced vEC damage, thus, shows high potential for preventing vein graft diseases.

Investigation of Neuropathology after Nerve Release in Chronic Constriction Injury of Rat Sciatic Nerve.

Peripheral compressive neuropathy causes significant neuropathic pain, muscle weakness and prolong neuroinflammation. Surgical decompression remains the gold standard of treatment but the outcome is suboptimal with a high recurrence rate. From mechanical compression to chemical propagation of the local inflammatory signals, little is known about the distinct neuropathologic patterns and the genetic signatures after nerve decompression. In this study, controllable mechanical constriction forces over rat sciatic nerve induces irreversible sensorimotor dysfunction with sustained local neuroinflammation, even 4 weeks after nerve release. Significant gene upregulations are found in the dorsal root ganglia, regarding inflammatory, proapoptotic and neuropathic pain signals. Genetic profiling of neuroinflammation at the local injured nerve reveals persistent upregulation of multiple genes involving oxysterol metabolism, neuronal apoptosis, and proliferation after nerve release. Further validation of the independent roles of each signal pathway will contribute to molecular therapies for compressive neuropathy in the future.

Thrombomodulin facilitates peripheral nerve regeneration through regulating M1/M2 switching.

BACKGROUND: Excessive inflammation within damaged tissue usually leads to delayed or insufficient regeneration, and nerves in the peripheral nervous system (PNS) generally do not recover fully following damage. Consequently, there is growing interest in whether modulation of the inflammatory response could help to promote nerve regeneration in the PNS. However, to date, there are no practical therapeutic strategies for manipulating inflammation after nerve injury. Thrombomodulin (TM) is a transmembrane glycoprotein containing five domains. The lectin-like domain of TM has the ability to suppress the inflammatory response. However, whether TM can modulate inflammation in the PNS during nerve regeneration has yet to be elucidated. METHODS: We investigated the role of TM in switching proinflammatory type 1 macrophages (M1) to anti-inflammatory type 2 macrophages (M2) in a human monocytic cell line (THP-1) and evaluated the therapeutic application of TM in transected sciatic nerve injury in rats. RESULTS: The administration of TM during M1 induction significantly reduced the expression levels of inflammatory cytokines, including TNF-a (p < 0.05), IL-6 (p < 0.05), and CD86 (p < 0.05), in THP-1 cells. Simultaneously, the expression levels of M2 markers, including IL-10 (p < 0.05) and CD206 (p < 0.05), were significantly increased in TM-treated THP-1 cells. Inhibition of IL-4R-c-Myc-pSTAT6-PPARγ signaling abolished the expression levels of IL-10 (p < 0.05) and CD206 (p < 0.05). The conditioned medium (CM) collected from M1 cells triggered an inflammatory response in primary Schwann cells, while CM collected from M1 cells treated with TM resulted in a dose-dependent reduction in inflammation. TM treatment led to better nerve regeneration when tested 6 weeks after injury and preserved effector muscle function. In addition, TM treatment reduced macrophage infiltration at the site of injury and led to potent M1 to M2 transition, thus indicating the anti-inflammatory capacity of TM. CONCLUSIONS: Collectively, our findings demonstrate the anti-inflammatory role of TM during nerve regeneration. Therefore, TM represents a potential drug for the promotion and modulation of functional recovery in peripheral nerves that acts by regulating the M1/M2 ratio.

FGF9 is a downstream target of SRY and sufficient to determine male sex fate in ex vivo XX gonad culture.

Fibroblast growth factor 9 (FGF9) is an autocrine/paracrine growth factor that plays critical roles in embryonic and organ developments and is involved in diverse physiological events. Loss of function of FGF9 exhibits male-to-female sex reversal in the transgenic mouse model and gain of FGF9 copy number was found in human 46, XX sex reversal patient with disorders of sex development. These results suggested that FGF9 plays a vital role in male sex development. Nevertheless, how FGF9/Fgf9 expression is regulated during testis determination remains unclear. In this study, we demonstrated that human and mouse SRY bind to -833 to -821 of human FGF9 and -1010 to -998 of mouse Fgf9, respectively, and control FGF9/Fgf9 mRNA expression. Interestingly, we showed that mouse SRY cooperates with SF1 to regulate Fgf9 expression, whereas human SRY-mediated FGF9 expression is SF1 independent. Furthermore, using an ex vivo gonadal culture system, we showed that FGF9 expression is sufficient to switch cell fate from female to male sex development in 12-16 tail somite XX mouse gonads. Taken together, our findings provide evidence to support the SRY-dependent, fate-determining role of FGF9 in male sex development.

Extracellular MicroRNA-92a Mediates Endothelial Cell-Macrophage Communication.

OBJECTIVE: Understanding message delivery among vascular cells is essential for deciphering the intercellular communications in cardiovascular diseases. MicroRNA (miR)-92a is enriched in endothelial cells (ECs) and circulation under atheroprone conditions. Macrophages are the primary immune cells in atherosclerotic lesions that modulate lesion development. Therefore, we hypothesize that, in response to atheroprone stimuli, ECs export miR-92a to macrophages to regulate their functions and enhance atherosclerotic progression. Approach and Results: We investigated the macrophage functions that are regulated by EC miR-92a under atheroprone microenvironments. We first determined the distributions of functional extracellular miR-92a by fractionating the intravesicular and extravesicular compartments from endothelial conditioned media and mice serum. The results indicate that extracellular vesicles are the primary vehicles for EC miR-92a transportation. Overexpression of miR-92a in ECs enhanced the proinflammatory responses and low-density lipoprotein uptake, while impaired the migration, of cocultured macrophage. Opposite effects were found in macrophages cocultured with ECs with miR-92a knockdown. Further analyses demonstrated that intravesicular miR-92a suppressed the expression of target gene KLF4 (Krüppel-like factor 4) in macrophages, suggesting a mechanism by which intravesicular miR-92a regulates recipient cell functions. Indeed, the overexpression of KLF4 rescued the EC miR-92a-induced macrophage atheroprone phenotypes. Furthermore, an inverse correlation of intravesicular miR-92a in blood serum and KLF4 expression in lesions was observed in atherosclerotic animals, indicating the potential function of extracellular miR-92a in regulating vascular diseases. CONCLUSIONS: EC miR-92a can be transported to macrophages through extracellular vesicles to regulate KLF4 levels, thus leading to the atheroprone phenotypes of macrophage and, hence, atherosclerotic lesion formation.

Anti-Cancer Effect of Cordycepin on FGF9-Induced Testicular Tumorigenesis.

Cordycepin, a bioactive constituent from the fungus Cordyceps sinensis, could inhibit cancer cell proliferation and promote cell death via induction of cell cycle arrest, apoptosis and autophagy. Our novel finding from microarray analysis of cordycepin-treated MA-10 mouse Leydig tumor cells is that cordycepin down-regulated the mRNA levels of FGF9, FGF18, FGFR2 and FGFR3 genes in MA-10 cells. Meanwhile, the IPA-MAP pathway prediction result showed that cordycepin inhibited MA-10 cell proliferation by suppressing FGFs/FGFRs pathways. The in vitro study further revealed that cordycepin decreased FGF9-induced MA-10 cell proliferation by inhibiting the expressions of p-ERK1/2, p-Rb and E2F1, and subsequently reducing the expressions of cyclins and CDKs. In addition, a mouse allograft model was performed by intratumoral injection of FGF9 and/or intraperitoneal injection of cordycepin to MA-10-tumor bearing C57BL/6J mice. Results showed that FGF9-induced tumor growth in cordycepin-treated mice was significantly smaller than that in a PBS-treated control group. Furthermore, cordycepin decreased FGF9-induced FGFR1-4 protein expressions in vitro and in vivo. In summary, cordycepin inhibited FGF9-induced testicular tumor growth by suppressing the ERK1/2, Rb/E2F1, cell cycle pathways, and the expressions of FGFR1-4 proteins, suggesting that cordycepin can be used as a novel anticancer drug for testicular cancers.

Regeneration of rete ridges in Lanyu pig (Sus scrofa): Insights for human skin wound healing.

Rete ridges are important to the mechanical function of skin in animals with minimal hair, including humans. As mice do not exhibit rete ridges, the need for a quality animal model is pertinent. Here, we develop a Lanyu pig (Sus scrofa) full-thickness wound model to explore tissue regeneration because the architecture and function are similar to humans and inbred genetic variants are available. Full- and partial-thickness wounds were generated on the dorsum. Full-thickness wounds at post-wound day 57 exhibit severe scar with no signs of wound-induced hair follicle neogenesis. Wound contraction is greater in the anterior/posterior relative to the medial/lateral axis. In wound beds, K14+ cells increased while K10+ , p63+ and PCNA+ cells decreased compared to unwounded tissue. Epithelial ß-catenin is unchanged. The wound bed expresses more ColI, less ColIII and no elastin. Rete ridges do not form after full-thickness wounding, but incompletely regenerate after partial-thickness wounding. An alkaline phosphatase (ALP)+ cell population, not associated with hair follicles, is present at the bottom of the rete ridge basal layer in pig and human unwounded skin. These K5+ /K10- /PCNA- /ALP+ epithelial cells are absent after full-thickness wounding but reappear after partial-thickness wounding, before invagination of new rete ridges. In summary, full-thickness wounding on the dorsum of Lanyu pigs results in scar formation and perturbed molecular expression while partial-thickness wounding permits limited rete ridge and papillary dermis regeneration. Future functional studies and further characterization will help contribute knowledge for the regenerative medicine field.

FGF9/FGFR2 increase cell proliferation by activating ERK1/2, Rb/E2F1, and cell cycle pathways in mouse Leydig tumor cells.

Fibroblast growth factor 9 (FGF9) promotes cancer progression; however, its role in cell proliferation related to tumorigenesis remains elusive. We investigated how FGF9 affected MA-10 mouse Leydig tumor cell proliferation and found that FGF9 significantly induced cell proliferation by activating ERK1/2 and retinoblastoma (Rb) phosphorylations within 15 minutes. Subsequently, the expressions of E2F1 and the cell cycle regulators: cyclin D1, cyclin E1 and cyclin-dependent kinase 4 (CDK4) in G1 phase and cyclin A1, CDK2 and CDK1 in S-G2 /M phases were increased at 12 hours after FGF9 treatment; and cyclin B1 in G2 /M phases were induced at 24 hours after FGF9 stimulation, whereas the phosphorylations of p53, p21 and p27 were not affected by FGF9. Moreover, FGF9-induced effects were inhibited by MEK inhibitor PD98059, indicating FGF9 activated the Rb/E2F pathway to accelerate MA-10 cell proliferation by activating ERK1/2. Immunoprecipitation assay and ChIP-quantitative PCR results showed that FGF9-induced Rb phosphorylation led to the dissociation of Rb-E2F1 complexes and thereby enhanced the transactivations of E2F1 target genes, Cyclin D1, Cyclin E1 and Cyclin A1. Silencing of FGF receptor 2 (FGFR2) using lentiviral shRNA inhibited FGF9-induced ERK1/2 phosphorylation and cell proliferation, indicating that FGFR2 is the obligate receptor for FGF9 to bind and activate the signaling pathway in MA-10 cells. Furthermore, in a severe combined immunodeficiency mouse xenograft model, FGF9 significantly promoted MA-10 tumor growth, a consequence of increased cell proliferation and decreased apoptosis. Conclusively, FGF9 interacts with FGFR2 to activate ERK1/2, Rb/E2F1 and cell cycle pathways to induce MA-10 cell proliferation in vitro and tumor growth in vivo.

Fibroblast Growth Factor 9 Suppresses Striatal Cell Death Dominantly Through ERK Signaling in Huntington's Disease.

BACKGROUND/AIMS: Huntington's disease (HD) is a heritable neurodegenerative disorder, and there is no cure for HD to date. A type of fibroblast growth factor (FGF), FGF9, has been reported to play prosurvival roles in other neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. However, the effects of FGF9 on HD is still unknown. With many similarities in the cellular and pathological mechanisms that eventually cause cell death in neurodegenerative diseases, we hypothesize that FGF9 might provide neuroprotective functions in HD. METHODS: In this study, STHdhQ7/Q7 (WT) and STHdhQ111/Q111 (HD) striatal knock-in cell lines were used to evaluate the neuroprotective effects of FGF9. Cell proliferation, cell death and neuroprotective markers were determined via the MTT assay, propidium iodide staining and Western blotting, respectively. The signaling pathways regulated by FGF9 were demonstrated using Western blotting. Additionally, HD transgenic mouse models were used to further confirm the neuroprotective effects of FGF9 via ELISA, Western blotting and immunostaining. RESULTS: Results show that FGF9 not only enhances cell proliferation, but also alleviates cell death as cells under starvation stress. In addition, FGF9 significantly upregulates glial cell line-derived neurotrophic factor (GDNF) and an anti-apoptotic marker, Bcl-xL, and decreases the expression level of an apoptotic marker, cleaved caspase 3. Furthermore, FGF9 functions through ERK, AKT and JNK pathways. Especially, ERK pathway plays a critical role to influence the effects of FGF9 toward cell survival and GDNF production. CONCLUSIONS: These results not only show the neuroprotective effects of FGF9, but also clarify the critical mechanisms in HD cells, further providing an insight for the therapeutic potential of FGF9 in HD.

Bioadhesive Polymersome for Localized and Sustained Drug Delivery at Pathological Sites with Harsh Enzymatic and Fluidic Environment via Supramolecular Host-Guest Complexation.

Targeted and sustained delivery of drugs to diseased tissues/organs, where body fluid exchange and catabolic activity are substantial, is challenging due to the fast cleansing and degradation of the drugs by these harsh environmental factors. Herein, a multifunctional and bioadhesive polycaprolactone-ß-cyclodextrin (PCL-CD) polymersome is developed for localized and sustained co-delivery of hydrophilic and hydrophobic drug molecules. This PCL-CD polymersome affords multivalent crosslinking action via surface CD-mediated host-guest interactions to generate a supramolecular hydrogel that exhibits evident shear thinning and efficient self-healing behavior. The co-delivery of small molecule and proteinaceous agents by the encapsulated PCL-CD polymersomes enhances the differentiation of stem cells seeded in the hydrogel. Furthermore, the PCL-CD polymersomes are capable of in situ grafting to biological tissues via host-guest complexation between surface CD and native guest groups in the tissue matrix both in vitro and in vivo, thereby effectively extending the retention of loaded cargo in the grafted tissue. It is further demonstrated that the co-delivery of small molecule and proteinaceous drugs via PCL-CD polymersomes averts cartilage degeneration in animal osteoarthritic (OA) knee joints, which are known for their biochemically harsh and fluidically dynamic environment.

Radiation sensitization of tumor cells induced by shear stress: the roles of integrins and FAK.

Recent studies revealed that the interstitial fluid flow in and around tumor tissue not only played an important role in delivering anticancer agents, but also affected the microenvironment, mostly hypoxia, in modulating tumor radio-sensitivity. The current study investigated the hypoxia-independent mechanisms of flow-induced shear stress in sensitizing tumors to radiation. Colon cancer cells were seeded onto glass slides pre-coated with fibronectin. A parallel-plate flow chamber system was used to impose fluid shear stress. Cell proliferation, apoptosis and colony assays were measured after shear stress and/or radiation. Cell cycle analysis and immunoblots of cell adhesion signal molecules were evaluated. The effect of shear stress was reversed by modulating integrin ß1 or FAK. Shear stress of 12dyne/cm(2) for 24h, but not 3h, enhanced the radiation induced cytotoxicity to colon cancer cells. Protein expression of FAK was significantly down-regulated but not transcriptionally suppressed. By modulating integrin ß1 and FAK expression, we demonstrated that shear stress enhanced tumor radiosensitivity by regulating integrin ß1/FAK/Akt as well as integrin ß1/FAK/cortactin pathways. Shear stress in combination with radiation might regulate integrins signaling by recruiting and activating caspases 3/8 for FAK cleavage followed by ubiquitin-mediated proteasomal degradation. Shear stress enhanced the radiation toxicity to colon cancer cells through suppression of integrin signaling and protein degradation of FAK. The results of our study provide a strong rationale for cancer treatment that combines between radiation and strategy in modulating tumor interstitial fluid flow.

RNA therapeutics for metabolic disorders.

The prevalence of metabolic disorders is increasing exponentially and has recently reached epidemic levels. Over the decades, a large number of therapeutic options have been proposed to manage these diseases but still show several limitations. In this circumstance, RNA therapeutics have rapidly emerged as a new hope for patients with metabolic diseases. 57 years have elapsed from the discovery of mRNA, a large number of RNA-based drug candidates have been evaluated for their therapeutic effectiveness and clinical safety under clinical studies. To date, there are seven RNA drugs for treating metabolic disorders receiving official approval and entering the global market. Their targets include hereditary transthyretin-mediated amyloidosis (hATTR), familial chylomicronemia syndrome, acute hepatic porphyria, primary hyperoxaluria type 1 and hypercholesterolemia, which are all related to liver proteins. All of these seven RNA drugs are antisense oligonucleotides (ASO) and small interfering RNA (siRNA). These two types of treatment are both based on oligonucleotides complementary to target RNA through Watson-Crick base-pairing, but their mechanisms of action include different nucleases. Such treatments show greatest potential among all types of RNA therapeutics due to consecutive achievements in chemical modifications. Another method, mRNA therapeutics also promise a brighter future for patients with a handful of drug candidates currently under development.

RNA therapeutics for regenerative medicine.

It is estimated that millions of people around the world experience various types of tissue injuries every year. Regenerative medicine was born and developed for understanding and application with the aim of replacing affected organs or some cells. The research, manufacture, production, and distribution of RNA in cells have acted as a basic foundation for the development and testing of therapies and treatments that are widely applied in different fields of medicine. Vaccines against COVID-19 are considered one of the brilliant and outstanding successes of RNA therapeutics research. With the characteristics of bio-derived RNA therapeutics, the mechanism of rapid implementation, safe production, and flexibility to create proteins depending on actual requirements. Based on the advantages above in this review, we discuss RNA therapeutics for regenerative medicine, and the types of RNA therapies currently being used for regenerative medicine. The relationship between disease and regenerative medicine is currently being studied or tested in RNA therapeutics. We have also covered the mechanisms of action of RNA therapy for regenerative medicine and some of the limitations in our current understanding of the effects of RNA therapy in this area. Additionally, we have also covered developing RNA therapeutics for regenerative medicine, focusing on RNA therapeutics for regenerative medicine. As a final point, we discuss potential applications for therapeutics for regenerative medicine in the future, as well as their mechanisms.

Turnover of PPP1R15A mRNA encoding GADD34 controls responsiveness and adaptation to cellular stress.

The integrated stress response (ISR) is a key cellular signaling pathway activated by environmental alterations that represses protein synthesis to restore homeostasis. To prevent sustained damage, the ISR is counteracted by the upregulation of growth arrest and DNA damage-inducible 34 (GADD34), a stress-induced regulatory subunit of protein phosphatase 1 that mediates translation reactivation and stress recovery. Here, we uncover a novel ISR regulatory mechanism that post-transcriptionally controls the stability of PPP1R15A mRNA encoding GADD34. We establish that the 3' untranslated region of PPP1R15A mRNA contains an active AU-rich element (ARE) recognized by proteins of the ZFP36 family, promoting its rapid decay under normal conditions and stabilization for efficient expression of GADD34 in response to stress. We identify the tight temporal control of PPP1R15A mRNA turnover as a component of the transient ISR memory, which sets the threshold for cellular responsiveness and mediates adaptation to repeated stress conditions.

Histone Trimethylations and HDAC5 Regulate Spheroid Subpopulation and Differentiation Signaling of Human Adipose-Derived Stem Cells.

Human adipose-derived stem cells (ASCs) have shown immense potential for regenerative medicine. Our previous work demonstrated that chitosan nano-deposited surfaces induce spheroid formation and differentiation of ASCs for treating sciatic nerve injuries. However, the underlying cell fate and differentiation mechanisms of ASC-derived spheroids remain unknown. Here, we investigate the epigenetic regulation and signaling coordination of these therapeutic spheroids. During spheroid formation, we observed significant increases in histone 3 trimethylation at lysine 4 (H3K4me3), lysine 9 (H3K9me3), and lysine 27 (H3K27me3), accompanied by increased histone deacetylase (HDAC) activities and decreased histone acetyltransferase activities. Additionally, HDAC5 translocated from the cytoplasm to the nucleus, along with increased nuclear HDAC5 activities. Utilizing single-cell RNA sequencing (scRNA-seq), we analyzed the chitosan-induced ASC spheroids and discovered distinct cluster subpopulations, cell fate trajectories, differentiation traits, and signaling networks using the 10x Genomics platform, R studio/language, and the Ingenuity Pathway Analysis (IPA) tool. Specific subpopulations were identified within the spheroids that corresponded to a transient reprogramming state (Cluster 6) and the endpoint cell state (Cluster 3). H3K4me3 and H3K9me3 were discovered as key epigenetic regulators by IPA to initiate stem cell differentiation in Cluster 6 cells, and confirmed by qPCR and their respective histone methyltransferase inhibitors: SNDX-5613 (a KMT2A inhibitor for H3K4me3) and SUVi (an SUV39H1 inhibitor for H3K9me3). Moreover, H3K9me3 and HDAC5 were involved in regulating downstream signaling and neuronal markers during differentiation in Cluster 3 cells. These findings emphasize the critical role of epigenetic regulation, particularly H3K4me3, H3K9me3, and HDAC5, in shaping stem cell fate and directing lineage-specific differentiation.

Human umbilical vein endothelial cells protect against hypoxic-ischemic damage in neonatal brain via stromal cell-derived factor 1/C-X-C chemokine receptor type 4.

BACKGROUND AND PURPOSE: Agents that protect against neurovascular damage provide a powerful neuroprotective strategy. Human umbilical vein endothelial cells (HUVECs) may be used to treat neonates with hypoxic-ischemia (HI) because of its autologous capability. We hypothesized that peripherally injected HUVECs entered the brain after HI, protected against neurovascular damage, and provided protection via stromal cell-derived factor 1/C-X-C chemokine receptor type 4 pathway in neonatal brain. METHODS: Postpartum day 7 rat pups received intraperitoneal injections of low-passage HUVEC-P4, high-passage HUVEC-P8, or conditioned medium before and immediately after HI. HUVECs were transfected with adenovirus-green fluorescent protein for cell tracing. Oxygen-glucose deprivation was established by coculturing HUVEC-P4 with mouse neuroblastoma neuronal cells (Neuro-2a) and with mouse immortalized cerebral vascular endothelial cells (b.End3). RESULTS: HUVEC-P4-treated group had more blood levels of green fluorescent protein-positive cells than HUVEC-P8-treated group 3 hours postinjection. Intraperitoneally injected HUVEC-P4, but not HUVEC-P8, entered the cortex after HI and positioned closed to the neurons and microvessels. Compared with the condition medium-treated group, the HUVEC-P4-treated but not the HUVEC-P8-treated group showed significantly less neuronal apoptosis and blood-brain barrier damage and more preservation of microvessels in the cortex 24 hours after HI. On postpartum day 14, the HUVEC-P4-treated group showed significant neuroprotection compared with the condition medium-treated group. Stromal cell-derived factor 1 was upregulated in the ipsilateral cortex 3 hours after HI, and inhibiting the stromal cell-derived factor 1/C-X-C chemokine receptor type 4 reduced the protective effect of HUVEC-P4. In vitro transwell coculturing of HUVEC-P4 also significantly protected against oxygen-glucose deprivation cell death in neurons and endothelial cells. CONCLUSIONS: Cell therapy using HUVECs may provide a powerful therapeutic strategy in treating neonates with HI.

Epigenetics in cancer development, diagnosis and therapy.

Cancer is a dangerous disease and one of the leading causes of death in the world. In 2020, there were nearly 10 million cancer deaths and approximately 20 million new cases. New cases and deaths from cancer are expected to increase further in the coming years. To have a deeper insight into the mechanism of carcinogenesis, epigenetics studies have been published and received much attention from scientists, doctors, and patients. Among alterations in epigenetics, DNA methylation and histone modification are studied by many scientists. They have been reported to be a major contributor in tumor formation and are involved in metastasis. From the understanding of DNA methylation and histone modification, effective, accurate and cost-effective methods for diagnosis and screening of cancer patients have been introduced. Furthermore, therapeutic approaches and drugs targeting altered epigenetics have also been clinically studied and have shown positive results in combating tumor progression. Several cancer drugs that rely on DNA methylation inactivation or histone modification have been approved by the FDA for the treatment of cancer patients. In summary, epigenetics changes such as DNA methylation or histone modification are take part in tumor growth, and they also have great prospect to study diagnostic and therapeutic methods of this dangerous disease.

Adipose-derived stem cells modulate neuroinflammation and improve functional recovery in chronic constriction injury of the rat sciatic nerve.

Introduction: Compressive neuropathy, a common chronic traumatic injury of peripheral nerves, leads to variable impairment in sensory and motor function. Clinical symptoms persist in a significant portion of patients despite decompression, with muscle atrophy and persistent neuropathic pain affecting 10%-25% of cases. Excessive inflammation and immune cell infiltration in the injured nerve hinder axon regeneration and functional recovery. Although adipose-derived stem cells (ASCs) have demonstrated neural regeneration and immunomodulatory potential, their specific effects on compressive neuropathy are still unclear. Methods: We conducted modified CCI models on adult male Sprague-Dawley rats to induce irreversible neuropathic pain and muscle atrophy in the sciatic nerve. Intraneural ASC injection and nerve decompression were performed. Behavioral analysis, muscle examination, electrophysiological evaluation, and immunofluorescent examination of the injured nerve and associated DRG were conducted to explore axon regeneration, neuroinflammation, and the modulation of inflammatory gene expression. Transplanted ASCs were tracked to investigate potential beneficial mechanisms on the local nerve and DRG. Results: Persistent neuropathic pain was induced by chronic constriction of the rat sciatic nerve. Local ASC treatment has demonstrated robust beneficial outcomes, including the alleviation of mechanical allodynia, improvement of gait, regeneration of muscle fibers, and electrophysiological recovery. In addition, locally transplanted ASCs facilitated axon remyelination, alleviated neuroinflammation, and reduced inflammatory cell infiltration of the injured nerve and associated dorsal root ganglion (DRG). Trafficking of the transplanted ASC preserved viability and phenotype less than 7 days but contributed to robust immunomodulatory regulation of inflammatory gene expression in both the injured nerve and DRG. Discussion: Locally transplanted ASC on compressed nerve improve sensory and motor recoveries from irreversible chronic constriction injury of rat sciatic nerve via alleviation of both local and remote neuroinflammation, suggesting the promising role of adjuvant ASC therapies for clinical compressive neuropathy.

Exploring the Potential of Stem Cell-Based Therapy for Aesthetic and Plastic Surgery.

Over the last decade, stem cell-associated therapies are widely used because of their potential in self-renewable and multipotent differentiation ability. Stem cells have become more attractive for aesthetic uses and plastic surgery, including scar reduction, breast augmentation, facial contouring, hand rejuvenation, and anti-aging. The current preclinical and clinical studies of stem cells on aesthetic uses also showed promising outcomes. Adipose-derived stem cells are commonly used for fat grafting that demonstrated scar improvement, anti-aging, skin rejuvenation properties, etc. While stem cell-based products have yet to receive approval from the FDA for aesthetic medicine and plastic surgery. Moving forward, the review on the efficacy and potential of stem cell-based therapy for aesthetic and plastic surgery is limited. In the present review, we discuss the current status and recent advances of using stem cells for aesthetic and plastic surgery. The potential of cell-free therapy and tissue engineering in this field is also highlighted. The clinical applications, advantages, and limitations are also discussed. This review also provides further works that need to be investigated to widely apply stem cells in the clinic, especially in aesthetic and plastic contexts.