CpG-Oligodeoxynucleotides Alleviate Tert-Butyl Hydroperoxide-Induced Macrophage Apoptosis by Regulating Mitochondrial Function and Suppressing ROS Production

7,8-dihydroxyflavone displayed antioxidant effect through activating HO-1 expression and inhibiting caspase-3/PARP activation in RAW264.7 cells

Flavonoids, which contain a benzo-γ-pyrone (C6-C3-C6) skeleton, have been reported to exhibit effective antioxidant ability. This study aimed to compare the antioxidant activities of 7,8-dihydroxyflavone (7,8-DHF) and 7-hydroxyflavone (7-HF) in H2 O2 , lipopolysaccharide (LPS), or tert-butyl hydroperoxide (t-BHP)-induced RAW264.7 cells, respectively. The antioxidant capacities of 7,8-DHF and 7-HF were firstly evaluated by 2,2-azinobis-3-ethyl-benzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Then, reactive oxygen species (ROS), super oxide dismutase (SOD), and malondialdehyde (MDA) productions in H2 O2 , LPS, or t-BHP-induced RAW264.7 cells were tested and compared, respectively. Finally, the antioxidant mechanisms of 7-HF and 7,8-DHF were initially investigated by western blot. Our results showed that 7,8-DHF possessed stronger free-radical scavenging capacity than 7-HF. Both 7,8-DHF and 7-HF suppressed MDA production and ROS accumulation, improved the activity of SOD in H2 O2 , LPS, or t-BHP-induced RAW264.7 cells, respectively. And 7,8-DHF exerted a better antioxidant effect than 7-HF, especially in t-BHP-induced oxidative stress. Mechanically, 7,8-DHF prevented the activation of poly ADP-ribosepolymerase and caspase-3, meanwhile markedly upregulated the expression of HO-1 protein in t-BHP-induced oxidative stress. These results suggested that 7,8-DHF might serve as a potential pharmaceutical drug against oxidative stress injury.

Oral Metformin Inhibits Choroidal Neovascularization by Modulating the Gut-Retina Axis

Purpose

Emerging data indicate that metformin may prevent the development of age-related macular degeneration (AMD). Whereas the underlying mechanisms of metformin's anti-aging properties remain undetermined, one proposed avenue is the gut microbiome. Using the laser-induced choroidal neovascularization (CNV) model, we investigate the effects of oral metformin on CNV, retinal pigment epithelium (RPE)/choroid transcriptome, and gut microbiota.

Methods

Specific pathogen free (SPF) male mice were treated via daily oral gavage of metformin 300 mg/kg or vehicle. Male mice were selected to minimize sex-specific differences to laser induction and response to metformin. Laser-induced CNV size and macrophage/microglial infiltration were assessed by isolectin and Iba1 immunostaining. High-throughput RNA-seq of the RPE/choroid was performed using Illumina. Fecal pellets were analyzed for gut microbiota composition/pathways with 16S rRNA sequencing/shotgun metagenomics, as well as microbial-derived metabolites, including small-chain fatty acids and bile acids. Investigation was repeated in metformin-treated germ-free (GF) mice and antibiotic-treated/GF mice receiving fecal microbiota transplantation (FMT) from metformin-treated SPF mice.

Results

Metformin treatment reduced CNV size (P < 0.01) and decreased Iba1+ macrophage/microglial infiltration (P < 0.005). One hundred forty-five differentially expressed genes were identified in the metformin-treated group (P < 0.05) with a downregulation in pro-angiogenic genes Tie1, Pgf, and Gata2. Furthermore, metformin altered the gut microbiome in favor of Bifidobacterium and Akkermansia, with a significant increase in fecal levels of butyrate, succinate, and cholic acid. Metformin did not suppress CNV in GF mice but colonization of microbiome-depleted mice with metformin-derived FMT suppressed CNV.

Conclusions

These data suggest that oral metformin suppresses CNV, the hallmark lesion of advanced neovascular AMD, via gut microbiome modulation.

Beauvericin exerts an anti-tumor effect on hepatocellular carcinoma by inducing PI3K/AKT-mediated apoptosis

Beauvericin is a world-spread mycotoxin isolated from the traditional Chinese medicine, Bombyx batryticatus (BB), which has been widely used to treat various neoplastic diseases. This study investigated the anti-hepatocellular carcinoma (HCC) activity of beauvericin and its potential mechanism. In this study, H22-bearing mice were intraperitoneally injected with 3, 5, 7 mg/kg of beauvericin once per-week over a three-week period. TUNEL staining determined the extent of tumor apoptosis induced by beauvericin. ELISA kits detected the level of IL-2, Perforin, and TNF-α, IFN-γ level in the serum. H22 hepatoma cells were exposed to beauvericin (5, 10, and 20 μmol/L) to investigate the underlying pathway. CCK-8 assay was used to observe the influence of beauvericin on the growth of H22 cells. Flow cytometry was used to detect the cell apoptosis and ROS level. Western blotting was performed to detect apoptotic and PI3K/AKT pathway protein production. The results showed that beauvericin could remarkably inhibit the growth of HCC in mice, combined with elevated TNF-α and IL-2. In vitro, beauvericin significantly promoted the generation of ROS, up-regulated Bax/Bcl-2 ratio and cleaved caspase-9, cleaved caspase-3 levels, down-regulated p-PI3K/PI3K ratio, p-AKT/AKT ratio, promoted the apoptosis of H22 cells, and inhibited the growth of H22 cells. Remarkably, treatment with PI3K/AKT activator (740Y-P and SC79) could prevent beauvericin-induced H22 cell apoptosis. These findings collectively indicate that beauvericin inhibits HCC growth by inducing apoptosis via the PI3K/AKT pathway.

Programmed cell death and lipid metabolism of macrophages in NAFLD

Non-alcoholic fatty liver disease (NAFLD) has now become the leading chronic liver disease worldwide with lifestyle changes. This may lead to NAFLD becoming the leading cause of end-stage liver disease in the future. To date, there are still no effective therapeutic drugs for NAFLD. An in-depth exploration of the pathogenesis of NAFLD can help to provide a basis for new therapeutic agents or strategies. As the most important immune cells of the liver, macrophages play an important role in the occurrence and development of liver inflammation and are expected to become effective targets for NAFLD treatment. Programmed cell death (PCD) of macrophages plays a regulatory role in phenotypic transformation, and there is also a certain connection between different types of PCD. However, how PCD regulates macrophage polarization has still not been systematically elucidated. Based on the role of lipid metabolic reprogramming in macrophage polarization, PCD may alter the phenotype by regulating lipid metabolism. We reviewed the effects of macrophages on inflammation in NAFLD and changes in their lipid metabolism, as well as the relationship between different types of PCD and lipid metabolism in macrophages. Furthermore, interactions between different types of PCD and potential therapeutic agents targeting of macrophages PCD are also explored.

Association Between Oral Metformin Use and the Development of Age-Related Macular Degeneration in Diabetic Patients: A Systematic Review and Meta-Analysis

Purpose

Metformin is a biguanide derivative that is commonly used for the treatment of diabetes mellitus (DM). It demonstrates antioxidative, anti-inflammatory, and antiangiogenic activity within the ocular tissue and thus may be implicated in the treatment of age-related macular degeneration (AMD). However, epidemiological studies have shown conflicting results.

Methods

The Ovid MEDLINE/Embase, Cochrane Library, and Web of Science databases were systematically searched from inception through August 3, 2022. Studies reporting the association between metformin use and odds of AMD were enrolled. Adjusted odds ratios (ORs) of AMD were extracted and pooled with random-effects model meta-analysis. Subgroup analyses based on AMD subtypes, ethnicity, study design, sex, and confirmation of AMD diagnosis were conducted.

Results

A total of 9 observational studies with 1,446,284 participants were included in the analysis. The meta-analysis showed that metformin use was associated with a significant reduction in the odds of AMD (pooled ORs = 0.81, 95% confidence interval [CI] = 0.70-0.93). Subgroup analyses revealed that metformin use was not significantly associated with dry or wet AMD. Black (pooled ORs = 0.61, 95% CI = 0.58-0.64) and Hispanic populations (pooled ORs = 0.85, 95% CI = 0.81-0.89) demonstrated significantly lower odds of AMD.

Conclusions

This systematic review and meta-analysis found that patients with DM with metformin usage were at lower odds of developing AMD. Future prospective clinical trials are needed to confirm this association.

Microbiota mitochondria disorders as hubs for early age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive neurodegenerative disease affecting the central area (macula lutea) of the retina. Research on the pathogenic mechanism of AMD showed complex cellular contribution governed by such risk factors as aging, genetic predisposition, diet, and lifestyle. Recent studies suggested that microbiota is a transducer and a modifier of risk factors for neurodegenerative diseases, and mitochondria may be one of the intracellular targets of microbial signaling molecules. This review explores studies supporting a new concept on the contribution of microbiota-mitochondria disorders to AMD. We discuss metabolic, vascular, immune, and neuronal mechanism in AMD as well as key alterations of photoreceptor cells, retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris endothelial, immune, and neuronal cells. Special attention was paid to alterations of mitochondria contact sites (MCSs), an organelle network of mitochondria, endoplasmic reticulum, lipid droplets (LDs), and peroxisomes being documented based on our own electron microscopic findings from surgically removed human eyes. Morphometry of Bruch's membrane lipids and proteoglycans has also been performed in early AMD and aged controls. Microbial metabolites (short-chain fatty acids, polyphenols, and secondary bile acids) and microbial compounds (lipopolysaccharide, peptidoglycan, and bacterial DNA)-now called postbiotics-in addition to local effects on resident microbiota and mucous membrane, regulate systemic metabolic, vascular, immune, and neuronal mechanisms in normal conditions and in various common diseases. We also discuss their antioxidant, anti-inflammatory, and metabolic effects as well as experimental and clinical observations on regulating the main processes of photoreceptor renewal, mitophagy, and autophagy in early AMD. These findings support an emerging concept that microbiota-mitochondria disorders may be a crucial pathogenic mechanism of early AMD; and similarly, to other age-related neurodegenerative diseases, new treatment approaches should be targeted at these disorders.

Severity of age-related macular degeneration at first presentation in Bhutan: a 3-year national study

Background

Medical services are still developing in Bhutan. There is no published national report on age-related macular degeneration (AMD). We therefore aim to determine the demographic characteristics and severity of AMD at first presentation among Bhutanese patients attending their recently inaugurated vitreoretinal (VR) clinics over a 3-year national survey, and to inform national health policy to develop suitable health program to prevent AMD-related blindness and visual impairment.

Methods

A retrospective cross-sectional consecutive case series study was conducted on all new AMD cases in Bhutan. If a patient presented with asymmetrical AMD, the eye with more severe AMD was considered. If both the eyes had the same severity one eye was chosen randomly. Collection of demographic data and clinical details including diagnostic testing (fundus photography, OCT and fluorescent angiography) and clinical staging were performed.

Results

Of 521 new AMD patients aged 71.9 ± 11.3 years, 306/521 (58.7%) were males (p = 0.005). At their first presentation, 234/521 patients (44.9%) already had late-stage AMD. Importantly, 69/234 patients (29.5%), that is half of total neovascular AMD (nAMD) patients, had disciform scars (DS) which were beyond treatment, and 7/234 patients (3.0%) had geographic atrophy (GA). Seven patients had retinal pigment epithelium tear at presentation. Fourteen of nineteen polypoidal choroidal vasculopathy (PCV) patients were younger than 50 years.

Conclusions

Half of nAMD cases presented as DS not amenable to the treatment. Many potentially treatable nAMD patients had already lost central vision and were legally blind. Young people with PCV losing vision early in life with longer morbidity-affected life and socio-economic burden was concerning. GA and DS cases need visual rehabilitation to improve their QoL. Incorporating a screening program for AMD with effective health education, and maintaining a national AMD Registry, would potentially lower AMD-related blindness and visual impairment.

Octadecaneuropeptide Alleviates Motor and Cognitive Impairments in Neonatal Rats Following Hypoxic-Ischemic Brain Damage

Hypoxic-ischemic brain damage (HIBD) is among the leading causes of neonatal brain injury. ODN, a peptide derived from diazepam-binding inhibitor (DBI), has potent antioxidant and anti-apoptotic properties. It remains unclear, however, whether ODN is an effective treatment for HIBD. Here, we reported that treatment with ODN (10 ng/day, i.c.v.) alleviated the deficits in myodynamia and motor coordination and cognitive functions in HIBD. Meanwhile, ODN prevented the neuronal loss in the cortex and hippocampus in HIBD rats. In addition, ODN decreased ROS by generating less oxidants and more antioxidants, as reflected by a dramatic increase in total antioxidant capacity, glutathione reductase, and catalase and a marked decrease in H₂O₂ and total nitric oxide synthase. Collectively, these data show ODN alleviates neuron injury and motor and memory deficits by attenuating ROS production and could be used as a novel molecular for treating HIBD.

Association of metformin treatment with enhanced effect of anti-VEGF agents in diabetic macular edema patients

PURPOSE

To investigate the effect of metformin combined with anti-VEGF agents in patients with diabetic macular edema (DME).

METHODS

This study was a prospective, nonrandomized case-control study. Patients were included in with a diagnosis of DME who received anti-VEGF agents injection. Basic information, medical history, best-corrected visual acuity (BCVA), central macular thickness (CMT), the number of intravitreal injections, panretinal photocoagulation (PRP), and macular grid photocoagulation treatment during the 6-month follow-up, were recorded for each patient.

RESULTS

A total of 50 DME patients were collected (24 patients with a history of oral metformin ≥ 6 months and 26 patients who had not taken metformin). The BCVA and the CMT were significantly improved after anti-VEGF treatment in two groups (F1 = 19.35, F2 = 26.78; F1 = 65.45, F2 = 76.23; P < 0.05). The BCVA in the metformin group was better than that in non-metformin group at every point after treatment (F = 34.45, P < 0.05). The CMT in metformin group decreased much more than that in non-metformin group during the follow-up period (F = 87.05, P < 0.05). The injection numbers decreased in the metformin group compared with the non-metformin group (t = 5.14, P < 0.05). However, there was no difference in PRP and macular grid photocoagulation therapy between the two groups during the 6-month follow-up.

CONCLUSION

Metformin can enhance the therapeutic effect of anti-VEGF agents on DME patients to improve their visual acuity, improve the structure of the macular area, and reduce the number of intravitreal injections 90.

TLR9 Signaling Protects Alcohol-Induced Hepatic Oxidative Stress but Worsens Liver Inflammation in Mice

Toll-Like Receptor 9 (TLR9) elicits cellular response to nucleic acids derived from pathogens or dead cells. Previous studies have shown that TLR9-driven response may lead to differential impact on the pathogenesis of liver diseases. This study aimed to determine how TLR9 may contribute to chronic alcohol exposure-induced liver pathogenesis. We observed that TLR9 KO mice were more susceptible to alcohol-induced liver injury, which was evidenced by higher serum ALT/AST levels and more lipid accumulation in alcohol-fed TLR9 KO mice than wild-type mice. Alcohol-induced oxidative stress and mitochondrial dysfunction were also exacerbated by TLR9 KO. We found that chronic alcohol exposure-induced hepatic CHOP and ATF6 activation were enhanced in TLR9 KO mice. By using primary hepatocytes and AML-12 cells, we confirmed that TLR9 activation by CpG ODN administration significantly ameliorated acetaldehyde-induced cell injury via suppressing ATF6-CHOP signaling. By using STAT3 knockdown AML12 cells, we showed that TLR9-mediated STAT3 activation inhibited ATF6-CHOP signaling cascade and thereby protecting against acetaldehyde-induced mitochondrial dysfunction and cell injury. Interestingly, we found that TLR9 KO mice ameliorate chronic alcohol exposure-induced CXCL1 induction and neutrophils infiltration in the liver. Furthermore, hepatocyte lack of STAT3 significantly ameliorated CpG ODN and LPS-increased CXCL1 levels in hepatocytes. Overall, our data demonstrate that TLR9 signaling in hepatocytes counteracts alcohol-induced hepatotoxicity but worsens proinflammatory response.