Age-related decline in melatonin contributes to enhanced osteoclastogenesis via disruption of redox homeostasis.

BACKGROUND: Increased oxidative stress contributes to enhanced osteoclastogenesis and age-related bone loss. Melatonin (MT) is an endogenous antioxidant and declines with aging. However, it was unclear whether the decline of MT was involved in the enhanced osteoclastogenesis during the aging process. METHODS: The plasma level of MT, oxidative stress status, bone mass, the number of bone marrow-derived monocytes (BMMs) and its osteoclastogenesis were analyzed in young (3-month old) and old (18-month old) mice (n = 6 per group). In vitro, BMMs isolated from aged mice were treated with or without MT, followed by detecting the change of osteoclastogenesis and intracellular reactive oxygen species (ROS) level. Furthermore, old mice were treated with MT for 2 months to investigate the therapeutic effect. RESULTS: The plasma level of MT was markedly lower in aged mice compared with young mice. Age-related decline in MT was accompanied by enhanced oxidative stress, osteoclastogenic potential and bone loss. MT intervention significantly suppressed the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis, decreased intracellular ROS and enhanced antioxidant capacity of BMMs from aged mice. MT supplementation significantly attenuated oxidative stress, osteoclastogenesis, bone loss and deterioration of bone microstructure in aged mice. CONCLUSIONS: These results suggest that age-related decline of MT enhanced osteoclastogenesis via disruption of redox homeostasis. MT may serve as a key regulator in osteoclastogenesis and bone homeostasis, thereby highlighting its potential as a preventive agent for age-related bone loss.

Research on the antipruritic active ingredients of Mikania micrantha.

Mikania micrantha is a perennial liana of the genus Mikania of the Asteraceae family. It is a commonly used medicine in South America for treating fever, malaria, dysentery, snake bites, etc. Because of its strong adaptability and ability to inhibit the growth of its associated plants, Mikania micrantha is considered an invasive species in China and is known as a plant killer. Preliminary studies have shown that Mikania micrantha has an antipruritic effect, but the antipruritic active substance is not yet clear. In this study, a 4-aminopyridine-induced itching model in mice was used to determine the antipruritic effects of petroleum ether, ethyl acetate, ethanol extraction site, and Mikania micrantha volatile oil. GC-MS was used to analyze the components of the antipruritic fractions, combined with mice itch-causing models to study the antipruritic effects of ß-caryophyllene and humulene. The safety of ß-caryophyllene was preliminarily evaluated through the acute toxicity test of mice skin. The ethyl acetate and volatile oil of Mikania micrantha have apparent antipruritic effects. Humulene and ß-caryophyllene have a quantitative-effective relationship to inhibit itching in mice. The acute toxicity test of mouse skin showed that ß-caryophyllene has no acute toxicity. This study indicated that the main antipruritic active ingredients of Mikania micrantha are ß-caryophyllene and humulene.

Magnetic-Actuated Jumping of Droplets on Superhydrophobic Grooved Surfaces: A Versatile Strategy for Three-Dimensional Droplet Transportation.

On-demand droplet transportation is of great significance for numerous applications. Although various strategies have been developed for droplet transportation, out-of-surface three-dimensional (3D) transportation of droplets remains challenging. Here, a versatile droplet transportation strategy based on magnetic-actuated jumping (MAJ) of droplets on superhydrophobic grooved surfaces (SHGSs) is presented, which enables 3D, remote, and precise manipulation of droplets even in enclosed narrow spaces. To trigger MAJ, an electromagnetic field is utilized to deform the droplet on the SHGS with the aid of an attached magnetic particle, thereby the droplet acquires excess surface energy. When the electromagnetic field is quickly removed, the excess surface energy is partly converted into kinetic energy, allowing the droplet to jump atop the surface. Through high-speed imaging and numerical simulation, the working mechanism and size matching effect of MAJ are unveiled. It is found that the MAJ behavior can only be observed if the sizes of the droplets and the superhydrophobic grooves are matched, otherwise unwanted entrapment or pinch-off effects would lead to failure of MAJ. A regime diagram which serves as a guideline to design SHGSs for MAJ is proposed. The droplet transportation capacities of MAJ, including in-surface and out-of-surface directional transportation, climbing stairs, and crossing obstacles, are also demonstrated. With the ability to remotely manipulate droplets in enclosed narrow spaces without using any mechanical moving parts, MAJ can be used to design miniaturized fluidic platforms, which exhibit great potential for applications in bioassays, microfluidics, droplet-based switches, and microreactions.

METTL3 confers protection against mitochondrial dysfunction and cognitive impairment in an Alzheimer disease mouse model by upregulating Mfn2 via N6-methyladenosine modification.

Mitofusin 2 (MFN2) has been found to be downregulated in patients with Alzheimer disease (AD) but little is known about its roles in the pathogenesis of AD. We explored the mechanism of N6-methyladenosine (m6A) methylation of Mfn2 in hippocampal mitochondrial dysfunction in an AD mouse model. APP/PS1 transgenic mice underwent stereotaxic injection of adeno-associated viruses and their behaviors were assessed. METTL3 and MFN2 expressions were measured by qRT-PCR and Western blot, accompanied by assessment of mitochondrial morphology, ATP, mitochondrial membrane potential, and amyloid-ß content. Binding between METTL3 and MFN2, the total amount of m6A, and the m6A modification of Mfn2 were also determined. METTL3 and MFN2 were downregulated in hippocampal tissues of the AD model mice; METTL3 enhanced MFN2 expression via m6A modification. Overexpression of METTL3 or MFN2 ameliorated mitochondrial dysfunction indicated by fewer damaged mitochondria, increased ATP and JC-1 levels, and reduced Aß content; improved cognitive impairment in the mice was indicated by the novel object discrimination index and Morris water maze tests. Effects of METTL3 overexpression were abrogated by further knockdown of MFN2. Thus, METTL3 ameliorated mitochondrial dysfunction and cognitive impairment in the AD model mice by increasing MFN2 expression via m6A modification.

Unconventional Dually-Mobile Superrepellent Surfaces.

The ability of water droplets to move freely on superrepellent surfaces is a crucial feature that enables effective liquid repellency. Common superrepellent surfaces allow free motion of droplets in the Cassie state, with the liquid resting on the surface textures. However, liquid impalement into the textures generally leads to a wetting transition to the Wenzel state and droplet immobilization on the surface, thereby destroying the liquid repellency. This study reports the creation of a novel type of superrepellent surface through rational structural control combined with liquid-like surface chemistry, which allows for the free movement of water droplets and effective repellency in both the Cassie and Wenzel states. Theoretical guidelines for designing such surfaces are provided, and experimental results are consistent with theoretical analysis. Furthermore, this work demonstrates the enhanced ice resistance of the dually-mobile superrepellent surfaces, along with their distinctive self-cleaning capability to eliminate internal contaminants. This study expands the understanding of superrepellency and offers new possibilities for the development of repellent surfaces with exceptional anti-wetting properties.

Xinyang tablet alleviated cardiac dysfunction in a cardiac pressure overload model by regulating the receptor-interacting serum/three-protein kinase 3/FUN14 domain containing 1-mediated mitochondrial unfolded protein response and mitophagy.

ETHNOPHARMACOLOGICAL RELEVANCE: Xinyang tablet (XYT) has been used for heart failure (HF) for over twenty years in clinical practice, but the underlying molecular mechanism remains poorly understood. AIMS OF THE STUDY: In the present study, we aimed to explore the protective effects of XYT in HF in vivo and in vitro. MATERIALS AND METHODS: Transverse aortic constriction was performed in vivo to establish a mouse model of cardiac pressure overload. Echocardiography, tissue staining, and real-time quantitative PCR (qPCR) were examined to evaluate the protective effects of XYT on cardiac function and structure. Adenosine 5'-triphosphate production, reactive oxygen species staining, and measurement of malondialdehyde and superoxide dismutase was used to detect mitochondrial damage. Mitochondrial ultrastructure was observed by transmission electron microscope. Immunofluorescence staining, qPCR, and Western blotting were performed to evaluate the effect of XYT on the mitochondrial unfolded protein response and mitophagy, and to identify its potential pharmacological mechanism. In vitro, HL-1 cells and neonatal mouse cardiomyocytes were stimulated with Angiotensin II to establish the cell model. Western blotting, qPCR, immunofluorescence staining, and flow cytometry were utilized to determine the effects of XYT on cardiomyocytes. HL-1 cells overexpressing receptor-interacting serum/three-protein kinase 3 (RIPK3) were generated by transfection of RIPK3-overexpressing lentiviral vectors. Cells were then co-treated with XYT to determine the molecular mechanisms. RESULTS: In the present study, XYT was found to exerta protective effect on cardiac function and structure in the pressure overload mice. And it was also found XYT reduced mitochondrial damage by enhancing mitochondrial unfolded protein response and restoring mitophagy. Further studies showed that XYT achieved its cardioprotective role through regulating the RIPK3/FUN14 domain containing 1 (FUNDC1) signaling. Moreover, the overexpression of RIPK3 successfully reversed the XYT-induced protective effects and significantly attenuated the positive effects on the mitochondrial unfolded protein response and mitophagy. CONCLUSIONS: Our findings indicated that XYT prevented pressure overload-induced HF through regulating the RIPK3/FUNDC1-mediated mitochondrial unfolded protein response and mitophagy. The information gained from this study provides a potential strategy for attenuating mitochondrial damage in the context of pressure overload-induced heart failure using XYT.

A simplified herbal decoction attenuates myocardial infarction by regulating macrophage metabolic reprogramming and phenotypic differentiation via modulation of the HIF-1α/PDK1 axis.

BACKGROUND: Myocardial infarction (MI) poses a global public health challenge, often associated with elevated mortality rates and a grim prognosis. A crucial aspect of the inflammatory injury and healing process post-MI involves the dynamic differentiation of macrophages. A promising strategy to alleviate myocardial damage after MI is by modulating the inflammatory response and orchestrating the shift from pro-inflammatory (M1) to anti-inflammatory (M2) macrophages, aiming to achieve a reduced M1/M2 ratio. Nuanxinkang (NXK), a simplified herbal decoction, has demonstrated noteworthy cardioprotective, inflammation-regulating, and myocardial energy metabolism-regulating properties. METHODS: In this study, we constructed an MI model by ligating coronary arteries to investigate the efficacy of NXK in improving ventricular remodeling and cardiac function. Mice were administered NXK (1.65 g/kg/d) or an equivalent volume of regular saline via gavage for 28 consecutive days, commencing the day after surgery. Then, we conducted echocardiography to assess the cardiac function, Masson staining to illustrate the extent of myocardial fibrosis, TUNEL staining to reveal myocardial apoptosis, and flow cytometry to analyze the polarization of M1 and M2 macrophages in the hearts. Besides, a lipopolysaccharide (LPS)-induced pro-inflammatory macrophage (M1) polarization model was implemented in RAW264.7 cells to elucidate the underlying mechanism of NXK in regulating macrophage polarization. RAW264.7 cells were pre-treated with or without NXK-containing serum. Oxidative stress was detected by MitoSox staining, followed by Seahorse energy metabolism assay to evaluate alterations in mitochondrial metabolic patterns and ATP production. Both In vivo and in vitro, HIF-1α and PDK1 were detected by fluorescent quantitative PCR and Western blotting. RESULTS: In vivo, MI mice exhibited a decline in cardiac function, adverse ventricular remodeling, and an increase in glycolysis, coupled with M1-dominant polarization mediated by the HIF-1α/PDK1 axis. Notably, robust responses were evident with high-dose NXK treatment (1.65 g/kg/day), leading to a significant enhancement in cardiac function, inhibition of cardiac remodeling, and partial suppression of macrophage glycolysis and the inflammatory phenotype in MI mice. This effect was achieved through the modulation of the HIF-1α/PDK1 axis. In vitro, elevated levels of mitochondrial ROS production and glycolysis were observed in LPS-induced macrophages. Conversely, treatment with NXK notably reduced the oxidative stress damage induced by LPS and enhanced oxidative phosphorylation (OXPHOS). Furthermore, NXK demonstrated the ability to modify the energy metabolism and inflammatory characteristics of macrophages by modulating the HIF-1α/PDK1 axis. The influence of NXK on this axis was partially counteracted by the HIF-1α agonist DMOG. And NXK downregulated PDK1 expression, curtailed glycolysis, and reversed LPS-induced M1 polarization in macrophages, similar to the PDK1 inhibitor DCA. CONCLUSION: In conclusion, NXK protects against MI-induced cardiac remodeling by inducing metabolic reprogramming and phenotypic differentiation of macrophages, achieved through the modulation of the HIF-1α/PDK1 axis. This provides a novel and promising strategy for the treatment of MI.

Accumulation of ß-aminoisobutyric acid mediates hyperalgesia in ovariectomized mice through Mas-related G protein-coupled receptor D signaling.

Hyperalgesia is typified by reduced pain thresholds and heightened responses to painful stimuli, with a notable prevalence in menopausal women, but the underlying mechanisms are far from understood. ß-Aminoisobutyric acid (BAIBA), a product of valine and thymine catabolism, has been reported to be a novel ligand of the Mas-related G protein coupled receptor D (MrgprD), which mediates pain and hyperalgesia. Here, we established a hyperalgesia model in 8-week-old female mice through ovariectomy (OVX). A significant increase in BAIBA plasma level was observed and was associated with decline of mechanical withdrawal threshold, thermal and cold withdrawal latency in mice after 6 weeks of OVX surgery. Increased expression of MrgprD in dorsal root ganglion (DRG) was shown in OVX mice compared to Sham mice. Interestingly, chronic loading with BAIBA not only exacerbated hyperalgesia in OVX mice, but also induced hyperalgesia in gonadally intact female mice. BAIBA supplementation also upregulated the MrgprD expression in DRG of both OVX and intact female mice, and enhanced the excitability of DRG neurons in vitro. Knockout of MrgprD markedly suppressed the effects of BAIBA on hyperalgesia and excitability of DRG neurons. Collectively, our data suggest the involvement of BAIBA in the development of hyperalgesia via MrgprD-dependent pathway, and illuminate the mechanisms underlying hyperalgesia in menopausal women.

Crosstalk between endothelial cells with a non-canonical EndoMT phenotype and cardiomyocytes/fibroblasts via IGFBP5 aggravates TAC-induced cardiac dysfunction.

Heart failure (HF) is a complex chronic condition characterized by structural and functional impairments. The differentiation of endothelial cells into myofibroblasts (EndoMT) in response to cardiac fibrosis is controversial, and the relative contribution of endothelial plasticity remains to be explored. Single-cell RNA sequencing was used to identify endothelial cells undergoing fibrotic differentiation within 2 weeks of transverse aortic constriction (TAC). This subset of endothelial cells transiently expressed fibrotic genes but had low expression of alpha-smooth muscle actin, indicating a non-canonical EndoMT, which we named a transient fibrotic-like phenotype (EndoFP). The role of EndoFP in pathological cardiac remodeling may be correlated with increased levels of osteopontin. Cardiomyocytes and fibroblasts co-cultured with EndoFP exhibited heightened pro-hypertrophic and pro-fibrotic effects. Mechanistically, we found that the upregulated expression of insulin-like growth factor-binding protein 5 may be a key mediator of EndoFP-induced cardiac dysfunction. Furthermore, our findings suggested that Rab5a is a novel regulatory gene involved in the EndoFP process. Our study suggests that the specific endothelial subset identified in TAC-induced pressure overload plays a critical role in the cellular interactions that lead to cardiac fibrosis and hypertrophy. Additionally, our findings provide insight into the mechanisms underlying EndoFP, making it a potential therapeutic target for early heart failure.