Melatonin's Protective Effects on Neurons in an in Vitro Cell Injury Model.

BACKGROUND: Currently, the role of melatonin (MT) in neuronal damage remains unclear and this study aimed to explore the protective effects of MT on neurons in an in vitro cell injury model. METHODS: The Sprague Dawley (SD) rat traumatic brain injury (TBI) model was prepared, and brain tissue extract (BTE) from the injured area were generated. To establish a cell injury model in vitro, the BTE was added to the culture medium during the neuron culture process. MT was introduced into the culture medium of the cell injury model to observe its protective effects on neurons. Relevant molecular biology experiments were conducted to observe cellular oxidative stress status, inflammation, endoplasmic reticulum (ER) stress, mitochondrial damage, and neuronal apoptosis. RESULTS: When compared to the control group, the BTE group exhibited a significant increase in cellular oxidative stress, inflammation, neurofilament light polypeptide (NEFL) expression, and ER stress. Additionally, the mitochondrial DNA (mtDNA) copy number significantly decreased, and there was a higher count of apoptotic cells (p < 0.05). Upon the addition of MT to the culture medium of the in vitro cell injury model, there was a significant reduction in cellular oxidative stress, inflammation, and NEFL levels. This addition also mitigated ER stress, increased mtDNA copy numbers, and decreased the ratio of cell apoptosis (p < 0.05). CONCLUSIONS: In the in vitro cell injury model, MT demonstrates the capacity to inhibit cellular oxidative stress, inflammation, and ER stress levels. Additionally, it diminishes mtDNA damage, fosters cell viability, and serves as a protective agent against both apoptosis and necrosis in neurons.

Nanomedicines Promote Cartilage Regeneration in Osteoarthritis by Synergistically Enhancing Chondrogenesis of Mesenchymal Stem Cells and Regulating Inflammatory Environment.

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive erosion of the articular cartilage and inflammation. Mesenchymal stem cells' (MSCs) transplantation in OA treatment is emerging, but its clinical application is still limited by the low efficiency in oriented differentiation. In our study, to improve the therapeutic efficiencies of MSCs in OA treatment by carbonic anhydrase IX (CA9) siRNA (siCA9)-based inflammation regulation and Kartogenin (KGN)-based chondrogenic differentiation, the combination strategy of MSCs and the nanomedicine codelivering KGN and siCA9 (AHK-CaP/siCA9 NPs) was used. In vitro results demonstrated that these NPs could improve the inflammatory microenvironment through repolarization of M1 macrophages to the M2 phenotype by downregulating the expression levels of CA9 mRNA. Meanwhile, these NPs could also enhance the chondrogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) by upregulating the pro-chondrogenic TGF-ß1, ACAN, and Col2α1 mRNA levels. Moreover, in an advanced OA mouse model, compared with BMSCs alone group, the lower synovitis score and OARSI score were found in the group of BMSCs plus AHK-CaP/siCA9 NPs, suggesting that this combination approach could effectively inhibit synovitis and promote cartilage regeneration in OA progression. Therefore, the synchronization of regulating the inflammatory microenvironment through macrophage reprogramming (CA9 gene silencing) and promoting MSCs oriented differentiation through a chondrogenic agent (KGN) may be a potential strategy to maximize the therapeutic efficiency of MSCs for OA treatment.

Mechanisms of fever-induced QT prolongation and torsades de pointes in patients with KCNH2 mutation.

AIMS: Patients with particular mutations of type-2 long QT syndrome (LQT2) are at an increased risk for malignant arrhythmia during fever. This study aimed to determine the mechanism by which KCNH2 mutations cause fever-induced QT prolongation and torsades de pointes (TdP). METHODS AND RESULTS: We evaluated three KCNH2 mutations, G584S, D609G, and T613M, in the Kv11.1 S5-pore region, identified in patients with marked QT prolongation and TdP during fever. We also evaluated KCNH2 M124T and R269W, which are not associated with fever-induced QT prolongation. We characterized the temperature-dependent changes in the electrophysiological properties of the mutant Kv11.1 channels by patch-clamp recording and computer simulation. The average tail current densities (TCDs) at 35°C for G584S, WT+D609G, and WT+T613M were significantly smaller and less increased with rising temperature from 35°C to 40°C than those for WT, M124T, and R269W. The ratios of the TCDs at 40°C to 35°C for G584S, WT+D609G, and WT+T613M were significantly smaller than for WT, M124T, and R269W. The voltage dependence of the steady-state inactivation curve for WT, M124T, and R269W showed a significant positive shift with increasing temperature; however, that for G584S, WT+D609G, and WT+T613M showed no significant change. Computer simulation demonstrated that G584S, WT+D609G, and WT+T613M caused prolonged action potential durations and early afterdepolarization formation at 40°C. CONCLUSION: These findings indicate that KCNH2 G584S, D609G, and T613M in the S5-pore region reduce the temperature-dependent increase in TCDs through an enhanced inactivation, resulting in QT prolongation and TdP at a febrile state in patients with LQT2.

The utility of zebrafish cardiac arrhythmia model to predict the pathogenicity of KCNQ1 variants.

Genetic testing for inherited arrhythmias and discriminating pathogenic or benign variants from variants of unknown significance (VUS) is essential for gene-based medicine. KCNQ1 is a causative gene of type 1 long QT syndrome (LQTS), and approximately 30% of the variants found in type 1 LQTS are classified as VUS. We studied the role of zebrafish cardiac arrhythmia model in determining the clinical significance of KCNQ1 variants. We generated homozygous kcnq1 deletion zebrafish (kcnq1del/del) using the CRISPR/Cas9 and expressed human Kv7.1/MinK channels in kcnq1del/del embryos. We dissected the hearts from the thorax at 48 h post-fertilization and measured the transmembrane potential of the ventricle in the zebrafish heart. Action potential duration was calculated as the time interval between peak maximum upstroke velocity and 90% repolarization (APD90). The APD90 of kcnq1del/del embryos was 280 ± 47 ms, which was significantly shortened by injecting KCNQ1 wild-type (WT) cRNA and KCNE1 cRNA (168 ± 26 ms, P < 0.01 vs. kcnq1del/del). A study of two pathogenic variants (S277L and T587M) and one VUS (R451Q) associated with clinically definite LQTS showed that the APD90 of kcnq1del/del embryos with these mutant Kv7.1/MinK channels was significantly longer than that of Kv7.1 WT/MinK channels. Given the functional results of the zebrafish model, R451Q could be reevaluated physiologically from VUS to likely pathogenic. In conclusion, functional analysis using in vivo zebrafish cardiac arrhythmia model can be useful for determining the pathogenicity of loss-of-function variants in patients with LQTS.

Enhanced cancer therapeutic efficiency of NO combined with siRNA by caspase-3 responsive polymers.

The combination of nitric oxide (NO) and siRNA is highly desirable for cancer therapy. Here, the furoxans-grafted PEI polymer (FDP) with caspase-3 responsive cleavable DEVD linker was synthesized, and used to bind siRNAs via electrostatic interaction and self-assembled into FDP/siRNA nanoplexes by hydrophobic force. After cellular uptake and lysosomal escape, the FDP/siRNA nanoplexes could achieve GSH-triggered NO release, and then increase the activity of caspase-3. The activated caspase-3 could specifically cleave the DEVD peptide sequence and enhance cell apoptosis. With the cleavage of DEVD peptide sequence, the disassembly of FDP/siRNA nanoplexes was further promoted, thereby resulting in increased siRNAs of ~40% were released at 48 h compared with the caspase-3 non-responsive FDnP/siRNA nanoplexes. By this way, cell apoptosis promotion and cell proliferation inhibition was achieved by siRNA-based downregulation of EGFR protein and the upregulated activity of caspase-3, followed by the enhanced cascade release of NO from FDP/siRNA nanoplexes. Furthermore, in vivo results demonstrated the improved anti-cancer efficiency of FDP/siEGFR nanoplexes without any detectable side effects. Therefore, it is believed that the caspase-3 responsive cleavable furoxans-grafted PEI polymers could provide a potential and efficient enhancement for cancer therapeutic efficiency by the co-delivery of nitric oxide and siRNA.

Annexin A1 alleviates kidney injury by promoting the resolution of inflammation in diabetic nephropathy.

Since failed resolution of inflammation is a major contributor to the progression of diabetic nephropathy, identifying endogenously generated molecules that promote the physiological resolution of inflammation may be a promising therapeutic approach for this disease. Annexin A1 (ANXA1), as an endogenous mediator, plays an important role in resolving inflammation. Whether ANXA1 could affect established diabetic nephropathy through modulating inflammatory states remains largely unknown. In the current study, we found that in patients with diabetic nephropathy, the levels of ANXA1 were upregulated in kidneys, and correlated with kidney function as well as kidney outcomes. Therefore, the role of endogenous ANXA1 in mouse models of diabetic nephropathy was further evaluated. ANXA1 deficiency exacerbated kidney injuries, exhibiting more severe albuminuria, mesangial matrix expansion, tubulointerstitial lesions, kidney inflammation and fibrosis in high fat diet/streptozotocin-induced-diabetic mice. Consistently, ANXA1 overexpression ameliorated kidney injuries in mice with diabetic nephropathy. Additionally, we found Ac2-26 (an ANXA1 mimetic peptide) had therapeutic potential for alleviating kidney injuries in db/db mice and diabetic Anxa1 knockout mice. Mechanistic studies demonstrated that intracellular ANXA1 bound to the transcription factor NF-κB p65 subunit, inhibiting its activation thereby modulating the inflammatory state. Thus, our data indicate that ANXA1 may be a promising therapeutic approach to treating and reversing diabetic nephropathy.

Myocyte-specific enhancer factor 2c triggers transdifferentiation of adipose tissue-derived stromal cells into spontaneously beating cardiomyocyte-like cells.

Cardiomyocyte regeneration is limited in adults. The adipose tissue-derived stromal vascular fraction (Ad-SVF) contains pluripotent stem cells that rarely transdifferentiate into spontaneously beating cardiomyocyte-like cells (beating CMs). However, the characteristics of beating CMs and the factors that regulate the differentiation of Ad-SVF toward the cardiac lineage are unknown. We developed a simple culture protocol under which the adult murine inguinal Ad-SVF reproducibly transdifferentiates into beating CMs without induction. The beating CMs showed the striated ventricular phenotype of cardiomyocytes and synchronised oscillation of the intracellular calcium concentration among cells on day 28 of Ad-SVF primary culture. We also identified beating CM-fated progenitors (CFPs) and performed single-cell transcriptome analysis of these CFPs. Among 491 transcription factors that were differentially expressed (≥ 1.75-fold) in CFPs and the beating CMs, myocyte-specific enhancer 2c (Mef2c) was key. Transduction of Ad-SVF cells with Mef2c using a lentiviral vector yielded CFPs and beating CMs with ~ tenfold higher cardiac troponin T expression, which was abolished by silencing of Mef2c. Thus, we identified the master gene required for transdifferentiation of Ad-SVF into beating CMs. These findings will facilitate the development of novel cardiac regeneration therapies based on gene-modified, cardiac lineage-directed Ad-SVF cells.

Biological activities of siRNA-loaded lanthanum phosphate nanoparticles on colorectal cancer.

Lanthanum can reduce absorption of phosphate by forming lanthanum phosphate complexes after oral administration of lanthanum carbonate tablets (FOSRENOL®) in patients. Based on the pH-responsive interaction of phosphate and lanthanum ions, the chitosan coated siRNA-loaded lanthanum phosphate nanoparticles (CS/LaP/siRNA NPs) were prepared for improving cancer treatment, in which polysaccharide chitosan was used as the outer shell to control the excessive growth of lanthanum phosphate complexes, and enable intestinal mucoadhesion. The CS/LaP/siEGFR NPs exhibited significant biological activities in human colorectal cancer HT-29 cells by the synergistic effects of siEGFRs and lanthanum ions, such as downregulation of EGFR and upregulation of miR-34a. Furthermore, significant tumor growth inhibition was observed in both transgenic C57BL/6-ApcMinC/Nju cancer mouse model and AOM/DSS chemically induced orthotopic colorectal cancer mouse model after intestinal instillation administration of CS/LaP/siEGFR NPs. Therefore, the lanthanum-based siRNA delivery system would provide a potential and efficient strategy for the treatment of colorectal cancers.

Impact of functional studies on exome sequence variant interpretation in early-onset cardiac conduction system diseases.

AIMS: The genetic cause of cardiac conduction system disease (CCSD) has not been fully elucidated. Whole-exome sequencing (WES) can detect various genetic variants; however, the identification of pathogenic variants remains a challenge. We aimed to identify pathogenic or likely pathogenic variants in CCSD patients by using WES and 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines as well as evaluating the usefulness of functional studies for determining them. METHODS AND RESULTS: We performed WES of 23 probands diagnosed with early-onset (<65 years) CCSD and analysed 117 genes linked to arrhythmogenic diseases or cardiomyopathies. We focused on rare variants (minor allele frequency < 0.1%) that were absent from population databases. Five probands had protein truncating variants in EMD and LMNA which were classified as 'pathogenic' by 2015 ACMG standards and guidelines. To evaluate the functional changes brought about by these variants, we generated a knock-out zebrafish with CRISPR-mediated insertions or deletions of the EMD or LMNA homologs in zebrafish. The mean heart rate and conduction velocities in the CRISPR/Cas9-injected embryos and F2 generation embryos with homozygous deletions were significantly decreased. Twenty-one variants of uncertain significance were identified in 11 probands. Cellular electrophysiological study and in vivo zebrafish cardiac assay showed that two variants in KCNH2 and SCN5A, four variants in SCN10A, and one variant in MYH6 damaged each gene, which resulted in the change of the clinical significance of them from 'Uncertain significance' to 'Likely pathogenic' in six probands. CONCLUSION: Of 23 CCSD probands, we successfully identified pathogenic or likely pathogenic variants in 11 probands (48%). Functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants in patients with CCSD. SCN10A may be one of the major genes responsible for CCSD.

Encapsulated microRNA by gemcitabine prodrug for cancer treatment.

Although microRNAs (miRNAs) function as the important tumor gene regulators, they still confront with many challenges in systemic delivery. Here, the amphiphilic gemcitabine-oleic acid prodrugs (GOA) binding miRNAs with hydrogen bond are assembled into nanoparticles (GOA/miR NPs) through hydrophobic interaction via denaturation-annealing processes and nano-precipitation technique. The non-cationic GOA/miR NPs with an average size of ~150 nm and a zeta potential of ~ - 15 mV exhibit a stable encapsulation of miRNAs with non-sequence selectivity. Either miR-122 or miR-34a encapsulated in the GOA/miR NPs is efficiently delivered into HepG2 cells and significantly downregulate the expression levels of target gene after lysosome escape and pH-responsive disassembly. Moreover, in vivo experiments demonstrate that the GOA/miR-122 NPs exhibit higher tumor accumulation. Compared to GOA micelles, GOA/miR-122 NPs displayed stronger tumor inhibition (73% regression) after intravenous injection in nude mice xenografted with HCC, along with rapid clearance in normal liver tissues. Furthermore, there is no significant influence on biochemical indicators and immune factors during the systematic administration of GOA/miR-122 NPs. The non-cationic GOA/miR NPs engineered by hydrogen bond interaction and hydrophobic forces show the enhanced synergistic antitumor efficacy and good biosafety, which will provide a potential nanomedcine for HCC treatment.

Regulating intracellular fate of siRNA by endoplasmic reticulum membrane-decorated hybrid nanoplexes.

Most cationic vectors are difficult to avoid the fate of small interfering RNA (siRNA) degradation following the endosome-lysosome pathway during siRNA transfection. In this study, the endoplasmic reticulum (ER) membrane isolated from cancer cells was used to fabricate an integrative hybrid nanoplexes (EhCv/siRNA NPs) for improving siRNA transfection. Compared to the undecorated Cv/siEGFR NPs, the ER membrane-decorated EhCv/siRNA NPs exhibits a significantly higher gene silencing effect of siRNA in vitro and a better antitumor activity in nude mice bearing MCF-7 human breast tumor in vivo. Further mechanistic studies demonstrate that functional proteins on the ER membrane plays important roles on improving cellular uptake and altering intracellular trafficking pathway of siRNA. It is worth to believe that the ER membrane decoration on nanoplexes can effectively transport siRNA through the endosome-Golgi-ER pathway to evade lysosomal degradation and enhance the silencing effects of siRNA.

Enhanced anti-tumor efficiency of gemcitabine prodrug by FAPα-mediated activation.

Gemcitabine (Gem) as an anti-cancer agent has been limited by its short circulation time and rapid metabolism that reflects in low tumor uptake and low therapeutic efficiency. To improve its anti-tumor activity, a novel FAPα enzyme-activated prodrug of Z-GP-Gem modified at 4-amino group of Gem was developed, which could effectively release parent Gem based on the specific cleavage via FAPα enzyme-activation in tumor microenvironment. Compared to Gem, the Z-GP-Gem prodrug exhibited significantly enhanced inhibition of both tumor growth and pulmonary metastasis in BALB/c mice bearing orthotopic breast 4T1 tumors. The Z-GP-Gem prodrug has a prolonged circulation time and a high tumor uptake based on the modification of Z-GP dipeptide at 4-amino group of Gem. These eventually caused a marked improvement in the systemic toxicity and the tumor growth inhibition in 4T1 cells. More interestingly, the unexpected depletion of tumor-associated fibroblast (TAF) was observed during the treatment of Z-GP-Gem prodrug in animal model. Therefore, these findings demonstrated that the FAPα-activated prodrug Z-GP-Gem would be a desirable approach for tumor therapy by intravenous administration.