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Cancer pain is one of the most common symptoms in patients with advanced cancer. In this study, we aimed to investigate the effects of the Mas-related gene C (MrgC) receptors on bone cancer pain. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured after the inoculation of Walker 256 mammary gland carcinoma cells into the tibia of adult Sprague-Dawley rats. The effects of MrgC receptor agonist bovine adrenal medulla 8-22 (BAM8-22) on nociceptive behaviors were investigated after intrathecal injection on days 16 and 17. Glial fibrillary acidic protein (GFAP)-positive cells in the spinal dorsal cord, and calcitonin gene related peptide (CGRP)-, neuronal nitric oxide synthase (nNOS)- and IL-1β-positive neurons in the dorsal root ganglia (DRG) were examined by immunofluorescence staining. The expression of nNOS and IL-1β proteins in the spinal dorsal horn and the DRG was examined by Western blotting after treatment with (Tyr6)-γ2-MSH-6-12 (MSH), which was another MrgC receptor agonist. The results showed that intrathecal injection of BAM8-22 (30 nmol) attenuated mechanical allodynia in a rat model of bone cancer pain and the effects could last for about 60 min, and single administration of BAM8-22 for two consecutive days reduced mechanical allodynia by about half on the third day. Moreover, the number of GFAP-positive cells in the spinal dorsal horn, and the number of CGRP-, nNOS- and IL-1β-positive neurons in the DRG were decreased. Similarly, intrathecal administration of MSH (15 nmol) reduced the expression of nNOS and IL-1β in the spinal dorsal horn and the DRG. In conclusion, activation of MrgC receptors suppresses the activation of astrocytes in the spinal dorsal cord and the expression of CGRP, nNOS, and IL-1β in the spinal dorsal cord and/or DRG, which may underlie the inhibition of bone cancer pain. These findings provide a novel strategy for the treatment of bone cancer pain.

The aim of this study was to conduct in vivo experiments using laser speckle contrast imaging (LSCI) technology to investigate the effects of high salt diet on renal vascular reactivity in mice. LSCI is a technology for monitoring blood flow based on the laser speckle principle. It has been widely used to detect microcirculatory functions in tissues such as the skin and brain. The kidneys are located behind the peritoneum, and their position is easily affected by the movement of abdominal organs. Measuring renal microcirculation in a living individual is difficult. The present study used a self-made kidney cup to isolate the kidney and fix its position relatively, and then applied LSCI technology to explore the effect of high salt diet (8% Na⁺) on renal vascular reactivity in male and female mice in vivo. The results showed that a short-term high salt diet (1 week) did not affect the systolic blood pressure of the tail artery, while significantly increased glomerular filtration rate (GFR) and renal blood flow (RBF). Compared with the normal salt diet group, the high salt diet group showed a significant decrease in the ratio of post-occlusive reactive hyperemia (PORH) in male mice, while there was no significant change in the PORH ratio in female mice. These results suggest that, although a short-term high salt diet does not cause changes in blood pressure, it has already affected renal vascular reactivity and has gender differences in its effects. Furthermore, the present study provides a basis for renal microcirculation assessment using LSCI in vivo.

Acute kidney injury (AKI) is a clinical syndrome characterized by a rapid decline in renal function. Renal ischemia-reperfusion injury (RIRI) is one of the main causes of AKI with the underlying mechanism incompletely clarified. The liver X receptors (LXRs), including LXRα and LXRβ, are members of the nuclear receptor superfamily. It has been shown that LXRs play an important role in regulating glucose and lipid metabolism, cholesterol efflux, and inflammation. The purpose of this study was to explore the role and mechanism of LXRs in RIRI. We determined the effects of LXR activation on renal function and histological changes in a mouse RIRI model and a cellular model of hypoxia/reoxygenation (H/R). In vivo results showed that LXRs agonist GW3965 significantly inhibited the increase of serum creatinine and urea nitrogen levels induced by RIRI. Both HE and PAS staining of kidney tissues revealed that GW3965 alleviated the morphological damages caused by RIRI. Immunohistochemical staining showed that GW3965 mitigated 4-HNE and GRP78 levels induced by RIRI. Furthermore, TUNEL assay indicated that GW3965 reduced RIRI-induced renal cell apoptosis. Quantitative real-time PCR (qPCR) analysis revealed that GW3965 attenuated RIRI-induced IL-6 and IL-1β mRNA expression. Compared with wild-type group, LXRα gene deficiency had little effect on RIRI-associated renal functional decline and morphological damages. Additionally, in vitro study demonstrated that GW3965 alleviated H/R-induced decrease of HK-2 human renal proximal tubule cell viability and restored the activity of superoxide dismutase (SOD) after H/R. Western blot results showed that GW3965 mitigated the increase of 4-HNE and GRP78 protein expression levels after H/R; However, knockdown of LXRβ using the small interfering RNA (siRNA) technique reduced cell viability compared to GW3965-treated group. Taken together, the LXRs agonist GW3965 significantly alleviates RIRI in mice possibly by reducing apoptosis, oxidative stress, endoplasmic reticulum stress and inflammation. These results also preliminarily confirm that the renal protective effects of LXRs agonists are dependent on LXRβ.

The objective of the present study was to investigate the role and mechanism of bone marrow microenvironmental cells in regulating the mitochondrial mass of leukemia cells, and to uncover the mechanism of leukemia progression at the metabolic level. A mouse model of acute myeloid leukemia (AML) induced by the overexpression of the MLL-AF9 (MA9) fusion protein was established, and the bone marrow cells of AML mice were transplanted into mitochondrial fluorescence reporter mice expressing the Dendra2 protein (mito-Dendra2 mice). The proportion of Dendra2⁺ cells in bone marrow leukemia cells at different stages of AML was quantified by flow cytometry. The effects of transferred mitochondria on leukemia cells were studied by fluorescence-activated cell sorting (FACS), followed by functional experiments and bulk RNA sequencing. Finally, components within the bone marrow niche, such as mesenchymal stromal cells (MSCs) and endothelial cells (ECs), were co-cultured with leukemia cells in vitro. The proportion of leukemia cells that underwent mitochondrial transfer and the apoptosis level of leukemia cells were then detected by flow cytometry. The results showed that mitochondria from bone marrow cells were transferred to leukemia cells in the AML mouse model, and the proportion of mitochondrial transfer decreased with AML progression. The proportion of mitochondria transferred to leukemia stem cells (LSCs) was lower than that of mature AML cells. In AML cells receiving Dendra2⁺ mitochondria, there was a significant increase in the levels of intracellular reactive oxygen species (ROS) and apoptosis, while the levels of protein translation and their colony-forming capacities were decreased. The transplantation of Dendra2⁺ AML cells resulted in an extension of the survival of mice. RNA sequencing analysis demonstrated a significant downregulation of pathways related to translation, aerobic respiration and mitochondrial organization in AML cells that had received mitochondria. In vitro co-culture experiments indicated that MSCs within the bone marrow niche tended to transfer their mitochondria to leukemia cells and promoted the apoptosis of leukemia cells. These results indicate that in the MA9-induced AML mouse model, bone marrow niche cells can transfer mitochondria to leukemia cells, resulting in a reduction in the overall survival and function of the leukemia cells. Mitochondrial transfer in the bone marrow microenvironment may serve as a self-defensive mechanism of the host bone marrow niche cells, inhibiting the progression of AML.

N6-methyladenosine (m⁶A) is the most common type of RNA modification in eukaryotes, which affects intracellular RNA metabolism and controls gene expression of related pathophysiological processes through dynamic reversible regulation of methyltransferases, demethylases and m⁶A-binding proteins. In recent years, the involvement of m⁶A methylation in the study of neuropathic pain has become a hot topic, some new understandings have been emerging, and m⁶A methylation has become a potential biological target for the treatment of neuropathic pain. Therefore, this article reviews the role and regulation of m⁶A methylation in neuropathic pain, in order to provide new enlightenment for the drug development and treatment of neuropathic pain.

Adipose tissue holds a pivotal position in maintaining systemic energy homeostasis. Brown adipose tissue (BAT) expresses uncoupling protein 1 (UCP1), which is specialized in dissipating chemical energy as heat to maintain euthermia, a process called non-shivering thermogenesis. Conversely, white adipocyte (WAT) predominantly serves as the primary reservoir for energy storage, while also exhibiting endocrine activity by secreting various adipokines, thereby modulating systemic metabolism. Under the stimulation of cold exposure, physical activity and pharmacological intervention, WAT can occur as "browning" or "beiging", and transform into beige adipose tissue. The morphology and function of beige adipocyte are similar to brown adipocyte, both of which express higher levels of UCP1 and also have the function of thermogenesis. Thus, exploring methods to regulate the functional homeostasis of adipose tissue and its underlying molecular mechanisms hold promise for advancing preventative and therapeutic approaches against metabolic diseases. Exosomes, a subtype of extracellular vesicles (EVs) with a diameter of 40-100 nm, facilitate intercellular communication in obese individuals and exert significant influence on insulin resistance and impaired glucose tolerance within adipose tissue. These effects are primarily mediated by microRNA (miRNA) transported by exosomes. MiRNA, originating from various cellular sources, traverses between different cell types via EVs, thereby orchestrating reciprocal functional modulation among diverse tissues and organs. This review systematically summarized the research progress in exosomal miRNA-mediated regulation of adipose tissue functional homeostasis, with the aim of offering novel insights into the diagnosis and treatment of obesity and associated metabolic diseases.

The etiology of rheumatoid arthritis (RA), a chronic inflammatory systemic disease, remains unclear. It is characterized by symmetrical and invasive joint inflammation, primarily affecting distal small joints such as those in the hands and feet. This inflammation can lead to joint deformity and loss of function, and often accompanied by involvement of extra-articular organs like the lungs and heart. Currently, anti-rheumatic drugs only provide symptom improvement but have toxic side effects that require optimization. Therefore, it is crucial to thoroughly analyze the mechanisms underlying RA development for the identification of new drug targets. Programmed cell death (PCD) has been extensively studied in recent years and proved to be one of the key pathogenic factors in RA. Dysregulation of PCD is particularly evident in synoviocytes, immune cells, and osteocytes. This review summarizes various forms of PCD including apoptosis, NETosis, autophagy, pyroptosis, necroptosis, ferroptosis, cuproptosis, as well as their regulatory roles in fibroblast synoviocytes, immune cells and osteocytes. These findings hold significant theoretical implications for optimizing clinical treatment options for RA and developing new target drugs.

Cerebral ischemia/reperfusion injury (CIRI) refers to secondary damage caused by reperfusion of blood flow following ischemic stroke. Its mechanism is complex, involving mitochondrial energy metabolism disorders, Ca²⁺ overload, oxidative stress, apoptosis, inflammatory responses, excitatory amino acid toxicity, blood-brain barrier disruption, excessive NO synthesis, and cell necrosis etc. Mitochondrial-associated endoplasmic reticulum membranes (MAMs) are specialized regions of the endoplasmic reticulum that play crucial roles in various cellular processes, including regulation of mitochondrial morphology and activity, lipid metabolism, Ca²⁺ homeostasis, and cell viability. Existing research has confirmed that mitochondrial homeostasis, cell apoptosis, and endoplasmic reticulum stress are closely related to MAMs. This article summarizes the research progress on MAMs in recent years, reviews the biological functions of MAMs and the localization of tethering proteins, analyzes the signaling between mitochondria and the endoplasmic reticulum, explores the impact of MAMs tethering proteins interaction on Ca²⁺ signaling and cell viability during the pathophysiological process of CIRI, aiming to provide a theoretical basis for the treatment of CIRI.

Tumors pose a significant global health concern and have long been a challenging issue in the medical field. Given its treatment dilemma, it is urgent to explore novel prevention and treatment strategies. Bilirubin, as a natural endogenous antioxidant, has the ability to inhibit the production of free radicals in the body, thereby alleviating the damage caused by oxidative stress to the organism. In recent years, the therapeutic effects of bilirubin in diseases mediated by oxidative stress and metabolic disorders have gradually gained widespread attention, demonstrating its potential therapeutic value for a variety of diseases. With further research, significant progress has also been made in the study of bilirubin in the field of oncology, suggesting its potential important role in the occurrence, development, and treatment of tumors. This article aims to review and summarize the recent advances in the study of bilirubin in the field of oncology, in order to provide new insights and guidance for the future directions of tumor diagnosis, prevention, and treatment.

The study aimed to explore the effect and mechanism of resistance exercise (RE) on cognitive dysfunction in type 2 diabetes mellitus (T2DM) mice. Six 8-week-old male m/m mice were used as control (Con) group, and db/db mice of the matched age were randomly divided into model control (db/db) group and db+RE group, with 6 mice in each group. The db+RE group was given 8 weeks of resistance climbing ladder exercise intervention. The fasting blood glucose and body weight of the mice were measured weekly. After the intervention, the spatial learning and memory of the mice were detected by Morris water maze, and the neuronal damage in the hippocampus of the mice was detected by Nissl staining. The protein expression levels of PSD93, PSD95, BDNF, CREB, p-CREB, IL-6, IL-1β, TNF-α, Iba-1, iNOS, CD206, Arg1, triggering receptor expressed on myeloid cells 2 (TREM2), NF-κB, p-STAT3, and STAT3 were detected by Western blot. The mRNA expression levels of inflammatory factors and TREM2 in hippocampus were evaluated by qRT-PCR, and the expression and localization of Iba-1, CD206, CD86, and TREM2 were determined by immunofluorescence staining. The results showed that the spatial learning and memory of the db/db group were significantly declined, the neurons in the hippocampus were damaged, the protein levels of PSD93, PSD95, BDNF, CD206, Arg1, TREM2 and the ratio of p-CREB/CREB were significantly down-regulated, the mRNA and protein expression levels of IL-6, IL-1β and TNF-α were significantly up-regulated, and the protein levels of iNOS, Iba-1, NF-κB and the ratio of p-STAT3/STAT3 were significantly increased compared with the Con group. However, the 8-week RE improved the spatial learning and memory of db/db mice, alleviated the damage of hippocampal neurons, promoted the polarization of M2 microglia, and inhibited the neuroinflammation. The above results suggest that RE can improve cognitive dysfunction in T2DM mice, and its mechanism may be related to regulating microglia polarization via TREM2/NF-κB/STAT3 signaling pathway.