Recent advances of m6A methylation in skeletal system disease.

Skeletal system disease (SSD) is defined as a class of chronic disorders of skeletal system with poor prognosis and causes heavy economic burden. m6A, methylation at the N6 position of adenosine in RNA, is a reversible and dynamic modification in posttranscriptional mRNA. Evidences suggest that m6A modifications play a crucial role in regulating biological processes of all kinds of diseases, such as malignancy. Recently studies have revealed that as the most abundant epigentic modification, m6A is involved in the progression of SSD. However, the function of m6A modification in SSD is not fully illustrated. Therefore, make clear the relationship between m6A modification and SSD pathogenesis might provide novel sights for prevention and targeted treatment of SSD. This article will summarize the recent advances of m6A regulation in the biological processes of SSD, including osteoporosis, osteosarcoma, rheumatoid arthritis and osteoarthritis, and discuss the potential clinical value, research challenge and future prospect of m6A modification in SSD.

Design, synthesis and anti-osteosarcoma activity study of novel pyrido[2,3-d]pyrimidine derivatives by inhibiting DKK1-Wnt/ß-catenin pathway.

Osteosarcoma is a common primary malignant bone tumor in adolescents. Wnt/ß-catenin has been proved to play a pro-oncogenic role and was overactivated in osteosarcoma. Therefore, this pathway has become an interesting therapeutic target for osteosarcoma. Herein we report the design, synthesis and biological activities of a series of novel pyrido[2,3-d]pyrimidine derivatives based on our previous work. Among these, the representative compound 2-{[1,3-dimethyl-7-(4-methylpiperazin-1-yl)-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidin-5-yl]amino}-N-[4-(trifluoromethoxy)phenyl]acetamide (7m) has exhibited good antiproliferative activity towards 143B and MG63 cells with good selectivity over non-cancerous HSF cells. In the assay of Ca2+ concentration, the compound 7m increased the intracellular Ca2+ concentration in 143B cells. In addition, the expression of DKK1 increased, and that of p-ß-catenin decreased by 7m treatment. Finally, the Hoechst 33,342 staining, Annexin-FITC/PI staining and mitochondrial fluorescence staining have clearly demonstrated that compound 7m induced apoptosis in 143B cells.

Coptisine Inhibits Influenza Virus Replication by Upregulating p21.

The activation of innate antiviral immunity is a promising approach for combatting viral infections. In this study, we screened Chinese herbs that activated human immunity and identified coptisine as a potent inhibitor of the influenza virus with an EC50 of 10.7 µM in MDCK cells. The time of an addition assay revealed that pre-treatment with coptisine was more effective at reducing viral replication than co-treatment or post-treatment. Our bulk RNA-sequencing data showed that coptisine upregulated the p21 signaling pathway in MDCK cells, which was responsible for its antiviral effects. Specifically, coptisine increased the expression of p21 and FOXO1 in a dose-dependent manner while leaving the MELK expression unchanged. Docking analysis revealed that coptisine likely inhibited MELK activity directly by forming hydrogen bonds with ASP-150 and GLU-87 in the catalytic pocket. These findings suggest that coptisine may be a promising antiviral agent that regulates the p21 signaling pathway to inhibit viral replication.

Targeted inhibition of TXNRD1 prevents cartilage extracellular matrix degeneration by activating Nrf2 pathway in osteoarthritis.

Osteoarthritis, a prevalent orthopedic disease, can affect the elderly and causes impairment. The degradation and aberrant homeostasis of cartilage extracellular matrix figure pivotally in the progression of osteoarthritis. Thioredoxin systems plays a role in a wide range of biological processes, including cell proliferation, apoptosis, and oxidative stress. The present study aimed to investigate the unique function and underlying pathophysiological mechanism of TXNRD1 in chondrocytes. An upregulated expression of TXNRD1 was observed in the articular cartilage of osteoarthritis patients compared with normal articular cartilage. Furthermore, in vitro experiments showed that the expression of TXNRD1 was also abnormally increased in IL-1ß-induced primary mouse chondrocytes. Silencing TXNRD1 using siRNA in chondrocytes could effectively inhibit the expression of ADAMTS5 and MMP13, and enhance the expression of COL2A1 and SOX9. The same was true for auranofin, an inhibitor of TXNRD1. This phenomenon indicated that inhibition of TXNRD1 attenuated il-1ß-induced metabolic imbalance of extracellular matrix (ECM) and the progression of chondrocyte osteoarthritis. Further mechanism analysis revealed that the activation of Nrf2 signaling pathway and the expression of heme oxygenase-1 (HO-1) were increased upon TXNRD1 inhibition. Furthermore, auranofin was found to attenuate DMM-induced osteoarthritis progression in vivo. Therefore, the pharmacological downregulation of TXNRD1 may provide an effective novel therapy for OA.

Molecular chaperone heat shock protein 70 inhibitors suppress conditioned place preference induced by morphine exposure in male rats.

Previous studies have indicated a role for molecular chaperone heat shock protein 70 (Hsp70) in the development of behavioural sensitization to morphine in rodents, suggesting that Hsp70 expression following morphine exposure is involved in molecular changes that may underlie addiction vulnerability. The current study was carried out to investigate the role of Hsp70 in the positive reinforcing properties of morphine using conditioned place preference (CPP) in male rats. An unbiased CPP procedure of three phases (pre-conditioning: d1-d3; conditioning: d4-d6; and testing: d7) was used. During the conditioning phase, morphine injections (5 mg/kg, subcutaneously) were administered to induce significant place preference. To explore the effect of Hsp70 on the development and expression of morphine CPP, Hsp70 inhibitors (PES, KNK437 and methylene blue) were administered into the lateral ventricle prior to either morphine conditioning sessions or a morphine challenge on the test day. Furthermore, Hsp70 expression within the mesocorticolimbic system was measured after the treatment with KNK437, a transcriptional inhibitor. We found that PES and KNK437, respectively, injected intracerebroventricularly dose-dependently attenuated both the development and expression of morphine CPP. Methylene blue treatment demonstrated an attenuation of the development, but had no effect on the expression of morphine CPP. Following KNK437 treatment, Hsp70 expression was significantly inhibited in the shell of nucleus accumbens (NAc) during both the development and expression of morphine CPP. The findings suggest that Hsp70 in the NAc shell plays an important role in the reinforcing effects of morphine and may be involved in the development of morphine dependence.

Mu-opioid receptors in septum mediate the development of behavioural sensitization to a single morphine exposure in male rats.

Behavioural sensitization (BS) is characterized by enhanced psychomotor responses to a dose of substance of abuse after prior repeated exposure. We previously reported that BS can be induced by a single injection of morphine in rats, whereas septal nuclei are specifically involved in the development phase of BS. Here, we demonstrated that intra-LS or intra-MS microinjections also incubated BS to a systemic morphine injection in a cross-sensitization fashion, whereas inactivation of either subdivision of septal nuclei (LS: lateral septum; MS: medial septum) can negate this ability of morphine. Then, non-selective (naloxone) and selective (µ-, δ- and κ-)opioid receptor antagonists were directly delivered into LS or MS, respectively, ahead of a morphine microinjection, whereas only µ-opioid receptors in both LS and MS play indispensable roles in mediating the BS development. Finally, there was a pronounced elevation in the levels of the monoamines (i.e. dopamine, homovanillic acid, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid) in the septum, 8 h after a morphine injection detected with a HPLC-ECD method, suggesting that dopaminergi and serotoninergic systems are implicated in the BS formation. Our studies demonstrated that septal nuclei critically participate in the BS development. Essentially, µ- instead of δ- or κ-opioid receptors in LS and MS mediate sensitization to opiates.

Design, Synthesis and Anticancer Activity of a New Series of N-aryl-N'-[4-(pyridin-2-ylmethoxy)benzyl]urea Derivatives.

The development of cancer treatments requires continuous exploration and improvement, in which the discovery of new drugs for the treatment of cancer is still an important pathway. In this study, based on the molecular hybridization strategy, a new structural framework with an N-aryl-N'-arylmethylurea scaffold was designed, and 16 new target compounds were synthesized and evaluated for their antiproliferative activities against four different cancer cell lines A549, MCF7, HCT116, PC3, and human liver normal cell line HL7702. The results have shown seven compounds with 1-methylpiperidin-4-yl groups having excellent activities against all four cancer cell lines, and they exhibited scarcely any activities against HL7702. Among them, compound 9b and 9d showed greatly excellent activity against the four kinds of cells, and the IC50 for MCF7 and PC3 cell lines were even less than 3 µM.

Brucine N-Oxide Reduces Ethanol Intake and Preference in Alcohol-Preferring Male Fawn-Hooded Rats.

BACKGROUND: Alcohol use disorder places a heavy burden on global public health systems and thus is in urgent need of improved pharmacotherapies. Previously, our group has demonstrated that 30 mg/kg of the indole alkaloid brucine significantly attenuates alcohol-drinking behavior; however, the high toxicity, poor water solubility, short half-life, and limited therapeutic window of brucine restrain its clinical application as an antialcoholism medication. We subsequently hypothesized that the oxide of brucine (brucine N-oxide) would produce a similar behavioral effect without the risk profile associated with brucine. METHODS: Male Fawn-Hooded rats with high innate alcohol preference underwent 2-bottle choice procedures (Experiments 1 to 3). Experiment 1 examined the effects of 7 daily BNO injections of 0, 30, 50, or 70 mg/kg (s.c.) on voluntary alcohol consumption (n = 9/group). Experiment 2 evaluated the impact of a single dose of 0 or 70 mg/kg BNO on the increased alcohol intake induced by a 4-day alcohol deprivation (n = 8/group). Experiment 3 tested the effect of 7 daily BNO injections of 0 or 70 mg/kg (s.c.) on sucrose preference (n = 6/group). Experiment 4 measured the median lethal dose (LD50) values of BNO and brucine to compare their acute toxicity in rats. Experiment 5 tested whether BNO (0, 30, 50, and 70 mg/kg, s.c.) affected locomotor activity using an open-field paradigm (n = 8/group). Finally, Experiment 6 evaluated the possible conditioned rewarding effects of 0, 30, 50, and 70 mg/kg BNO using the conditioned place preference paradigm (n = 6/group). RESULTS: BNO administration dose-dependently attenuated alcohol consumption without affecting food intake, total fluid consumption, or the natural preference for a sucrose solution, with 70 mg/kg BNO reducing consumption by 22.8%. A single dose of 70 mg/kg BNO significantly inhibited the alcohol deprivation effect. The LD50 values of BNO and brucine in rats were determined to be 1,103.5 ± 177.0 mg/kg and 264.6 ± 17.7 mg/kg, respectively. Finally, BNO administration did not affect spontaneous locomotor activity or induce a place preference. CONCLUSIONS: BNO may help to control excessive alcohol use and should be considered a treatment strategy for future study and development.

Effect of heat shock protein 70 modulators on the development of morphine analgesic tolerance in rats.

The clinical use of opioid analgesics, such as morphine, is limited by analgesic tolerance, molecular mechanism of which is not well understood. Recently, molecular chaperone heat shock protein 70 (Hsp70) has been demonstrated to play important roles in morphine-induced neuroadaptation. Here, we focused on the involvement of Hsp70 in the development of analgesic tolerance to morphine. Rats were treated with morphine (5, 10, 20 mg/kg, subcutaneously) or saline once daily for 10 consecutive days. Hsp70 modulator N-formyl-3, 4-methylenedioxybenzylidine-γ-butyrolactam [KNK437, 100 mg/kg, intraperitoneally (i.p.)], geranylgeranylacetone (500 mg/kg, i.p.) or pifithrin-µ (20 mg/kg, i.p.) was administered before morphine (10 mg/kg, subcutaneously)/saline treatment. Analgesic effect of morphine was measured using the tail-flick latency test, and Hsp70 protein expression was examined by western blot. Analgesic effect of morphine decreased gradually with the increase in the number of days of morphine injection, indicating development of analgesic tolerance. A significant increase of Hsp70 expression in the periaqueductal gray was observed during the development of analgesic tolerance after repeated morphine injections. The development of morphine analgesic tolerance was suppressed by pre-treatment with Hsp70 transcriptional inhibitor KNK437 or functional antagonist pifithrin-µ, while promoted by pre-treatment with Hsp70 transcriptional inducer geranylgeranylacetone. Our results demonstrated that the development of morphine analgesic tolerance was dual regulated by Hsp70 modulators, suggesting Hsp70 as an interesting and new target for preventing the development of opioid analgesic tolerance.

Protective and restorative effects of the traditional Chinese medicine Jitai tablet against methamphetamine-induced dopaminergic neurotoxicity.

BACKGROUND: Methamphetamine (METH) is a psychostimulant with high abuse liability that affects the monoamine neurotransmitter systems, particularly the dopamine system. Currently there are no effective medications for the treatment of METH abuse to restore METH-induced dopaminergic dysfunction. The Jitai tablet (JTT), a commercial traditional Chinese medicinal preparation, has been shown to modulate the dopaminergic function both in heroin addicts and in morphine-dependent rats. The purpose of this study was to investigate, in a rodent model, whether JTT can protect against METH-induced neurotoxicity, and/or restore METH-damaged dopaminergic function. METHODS: Immunohistochemical staining and/or autoradiography staining were used to detect tyrosine hydroxylase (TH) expression in the substantia nigra, and to examine the levels of dopamine transporter (DAT), dopamine D2 receptor (D2R) and TH levels in the striatum. Using a stereotyped behavior rating scale, we evaluated the inhibitory effect of JTT on METH-induced behavioral sensitization. RESULTS: Repeated METH administration induced obvious stereotyped behavior and neurotoxicity on the dopaminergic system. Pre-treatment with JTT significantly attenuated METH-induced stereotyped responses, and interdicted METH-induced changes in the levels of DAT, D2R and TH expression. Treatment with JTT after METH administration restored DAT, D2R and TH expression to normal levels. CONCLUSIONS: Our results indicated that JTT protects against METH-induced neurotoxicity and restores the dopaminergic function, and thus might be a potential treatment for the dopaminergic deficits associated with METH abuse.

Effect of Slip Time in Forming Neo-Esophageal Stenosis After Replacement of a Thoracic Esophagus With Nitinol Artificial Esophagus.

Attempts have been made to investigate the effect of slip time of nitinol artificial esophagus for forming neo-esophageal stenosis after replacement of a thoracic esophagus with nitinol artificial esophagus in 20 experimental pigs. The pigs whose slip time was less than 90 days postoperatively had severe dysphagia (Bown's III) immediately after they were fed, and the dysphagia aggravated gradually later on (Bown's III-IV). The pigs whose slip time was more than 90 days postoperatively had mild/moderate dysphagia (Bown's I-II) immediately after they were fed, and the dysphagia relieved gradually later on (Bown's II-I-0). The ratios between the diameter of neo-esophagus in different slip time and normal esophagus were 25% (at 2 months postoperatively), 58% (at 4 months postoperatively), and 93% (at 6 months postoperatively), respectively. The relationship between nitinol artificial esophagus slip time and neo-esophageal stenosis showed a positive correlation. After replacement of a thoracic esophagus with nitinol artificial esophagus, the artificial esophageal slip time not only affected the original diameter of the neo-esophagus immediately, but also affected the neo-esophageal scar stricture forming process later on. The narrowing of neo-esophagus is caused by overgrowth of scar tissue. But there is the positive correlation between artificial esophagus slip time and neo-esophageal stenosis, so this can be a way of overcoming neo-esophageal stenosis by delaying slip time of artificial esophagus.

Effects of Jitai tablet, a traditional Chinese medicine, on spontaneous withdrawal symptoms and modulation of dopaminergic functions in morphine-dependent rats.

Chronic opioid abuse can cause damage to dopamine neurons. However, there are currently no effective pharmacotherapies to reverse this damage, even though progress has been made in the development of therapeutic strategies for opioid dependence. The Jitai tablet (JTT) is a traditional Chinese medicine formulation most commonly used for opioid addiction treatment in China. In a morphine spontaneous withdrawal rat model we investigated the effects of JTT, either given before (pre-treatment) or after (post-treatment) morphine administration, on the dopamine system. Our study has shown the following: (1) pre- and post-treatment with JTT were effective at alleviating the wet dog shakes and episodes of writhing; (2) pre-treatment with JTT inhibited the morphine-induced decreases in dopamine transporter (DAT), dopamine D2 receptor (D2 R) and tyrosine hydroxylase (TH) levels in the striatum (p < 0.01, compared with morphine group) and maintained them at normal levels; and (3) post-treatment with JTT restored the densities of DAT, D2 R and TH in the striatum to normal levels (p < 0.01, compared with morphine group). These results support the notion that modulation of the dopamine system in the striatum may play a role for JTT's therapeutic effect on the alleviation of opioid withdrawal symptoms.

Chaperone heat shock protein 70 in nucleus accumbens core: a novel biological target of behavioural sensitization to morphine in rats.

Drug addiction is a major public health issue, yet the underlying adaptation of neural networks by drugs of abuse is not fully understood. We have previously linked chaperone heat shock protein 70 (Hsp70) to drug-induced adaptations. Focusing on the NAc core and shell, the present study aims to provide further findings for our understanding of the relation between behavioural sensitization to morphine and Hsp70 at transcriptional and functional levels in rats. Firstly, we delineated the characteristics of behavioural sensitization induced by a single morphine exposure (1-10 mg/kg, s.c.). Secondly, Hsp70 protein expression in the NAc core was time- and dose-relatedly induced during the development of behavioural sensitization to a single morphine exposure in rats, and Pearson analysis indicated a positive correlation between behavioural sensitization and Hsp70 expression in NAc core. Thirdly, at the transcriptional level, intra-NAc core injection of the specific heat shock factor-I (HSF-I) inhibitor N-Formyl-3,4-methylenedioxy-benzylidine-γ-butyrolactam (KNK437) suppressed Hsp70 expression and the development of behavioural sensitization, while the HSF-I specific inducer geranylgeranylacetone (GGA) promoted both of them. Interestingly, intra-NAc shell injection of KNK437 or GGA did not affect the development of behavioural sensitization. Finally, both the functional inhibition of Hsp70 ATPase activity by methylene blue (MB), and the antagonism of Hsp70 substrate binding site (SBD) activity by pifithrin-µ (PES) impaired the development of behavioural sensitization when they were microinjected into the NAc core. Taken together, the critical involvement of chaperone Hsp70 in behavioural sensitization to morphine identifies a biological target for long-lasting adaptations with relevance to addiction.

Brucine suppresses ethanol intake and preference in alcohol-preferring Fawn-Hooded rats.

AIM: Brucine (BRU) extracted from the seeds of Strychnos nux-vomica L is glycine receptor antagonist. We hypothesize that BRU may modify alcohol consumption by acting at glycine receptors, and evaluated the pharmacodynamic profiles and adverse effects of BRU in rat models of alcohol abuse. METHODS: Alcohol-preferring Fawn-Hooded (FH/Wjd) rats were administered BRU (10, 20 or 30 mg/kg, sc). The effects of BRU on alcohol consumption were examined in ethanol 2-bottle-choice drinking paradigm, ethanol/sucrose operant self-administration paradigm and 5-d ethanol deprivation test. In addition, open field test was used to assess the general locomotor activity of FH/Wjd rats, and conditioned place preference (CPP) was conducted to assess conditioned reinforcing effect. RESULTS: In ethanol 2-bottle-choice drinking paradigm, treatment with BRU for 10 consecutive days dose-dependently decreased the ethanol intake associated with a compensatory increase of water intake, but unchanged the daily total fluid intake and body weight. In ethanol/sucrose operant self-administration paradigms, BRU (30 mg/kg) administered before each testing session significantly decreased the number of lever presses for ethanol and the ethanol intake, without affecting the number of sucrose (10%) responses, total sucrose intake, and the number of lever presses for water. Acute treatment with BRU (30 mg/kg) completely suppressed the deprivation-induced elevation of ethanol consumption. Treatment with BRU (10, 20, and 30 mg/kg) did not alter locomotion of FH/Wjd rats, nor did it produce place preference or aversion. CONCLUSION: BRU selectively decreases ethanol consumption with minimal adverse effects. Therefore, BRU may represent a new pharmacotherapy for alcoholism.

An-jun-ning, a traditional herbal formula, attenuates spontaneous withdrawal symptoms via modulation of the dopamine system in morphine-dependent rats.

BACKGROUND: The dopamine system, which is involved in drug dependence, can be damaged by opioid abuse. However, current clinical medicines cannot reverse these damages in the brain, which are believed to be a key reason for the high relapse rate after abstinence treatment. This study aimed to investigate the effects of An-jun-ning (AJN), a commercial traditional Chinese medicine formula used for the treatment of opioid addiction, on the dopamine system in morphine-dependent rats and to explore the possible mechanism underlying its therapeutic effects. METHODS: The morphine dependence model was obtained through injections of morphine at increasing doses for 8 days. The AJN pre-treatment group was administered AJN 30 min before each morphine administration, and the AJN post-treatment groups were treated with AJN for 10 days after withdrawal. Spontaneous withdrawal symptoms (wet dog shakes, and episodes of writhing) were observed after withdrawal. Autoradiography study and/or immunohistochemical staining were used to examine the levels of dopamine transporter (DAT), dopamine D2 receptor (D2R) and tyrosine hydroxylase (TH). RESULTS: (1) Pre-treatment with AJN attenuates wet dog shakes and episodes of writhing to approximately 50% or less of those observed in the morphine group (p < 0.01). (2) AJN post-treatment dose-dependently reduced the number of wet dog shakes (p < 0.01), and the episodes of writhing (p < 0.01). (3) Pre-treatment with AJN effectively interdicted the morphine-induced decreases in the levels of DAT, D2R, and TH in the striatum (p < 0.01) such that they remained at nearly normal levels. (4) Post-treatment with AJN restored DAT and D2R to the normal levels (p < 0.01) and the level of TH to 87% of normal in the striatum. CONCLUSIONS: AJN can effectively alleviate opioid withdrawal symptoms and preserve or restore the DAT, D2R, and TH levels in the striatum. The mechanism underlying the effect of AJN on withdrawal symptoms may be related to the modulation of the dopamine system by AJN. These results suggest that AJN may help to prevent relapse in opioid dependence treatment.

Deficits of the "Good" Eye in Amblyopia: Processing Geometric Properties.

Purpose: Although fellow eyes of amblyopia are typically considered normal, recent studies have revealed impairments in certain aspects of vision. However, it remains unclear at which level of object processing these impairments occur. This study aims to investigate the functional level of visual perception impairment in the fellow eye of children and adults with amblyopia using the geometric functional hierarchy discrimination task based on Klein Mathematics methodology. Methods: Seventy-six patients with amblyopia (40 children and 36 adults) and 77 age-matched healthy controls (40 children and 37 adults) were recruited for this study. The participants completed four sets of geometric hierarchies (in ascending order of stability: Euclidean, affine, projective, and topology) and one set of color discrimination tasks. They were instructed to rapidly and accurately select a distinct shape from the four quadrants. Results: The participants' performance was evaluated using the inverse efficiency (IE) score (IE = response time (RT)/accuracy). The results of IEs show that the fellow eye of children with amblyopia exhibits normal topological processing, yet displays higher IEs in other geometric properties and color processing, suggesting impairments in these specific discrimination abilities. However, adults with amblyopia did not show deficits on any discrimination types compared with adult controls. Conclusions: The lack of compromised topological processing suggests that amblyopia may not have inflicted any damage to the subcortical visual pathways. Furthermore, these deficits observed in the fellow eye tend to diminish significantly during adulthood, implying that amblyopia may potentially hinder the maturation process of the fellow eye.

Basal metabolic rate mediates the causal relationship between gut microbiota and osteoarthritis: a two-step bidirectional Mendelian randomization study.

Background: The relationship between gut microbiota and osteoarthritis (OA) occurrence remains unclear. Existing research needs to clearly understand how basal metabolic rate (BMR) regulates this relationship. Therefore, using a two-step bidirectional Mendelian Randomization approach, our study aims to investigate whether BMR levels mediate the causal relationship between gut microbiota and OA. Methods: In this study, we examined publicly available summary statistics from Genome-Wide Association Studies (GWAS) to determine the correlation between gut microbiota and OA. The analysis included one primary dataset and two secondary datasets. Initially, a two-step, two-sample, and reverse MR analysis was performed to identify the causal relationship between gut microbiota and OA. Subsequently, a two-step MR analysis revealed that the relationship between microbiota and OA is mediated by BMR. Sensitivity analyses confirmed the robustness of the study results. Results: In our analysis of the primary dataset, we discovered a positive correlation between three taxa and the outcome of OA, and eight taxa exhibited a negative correlation with the OA outcome. Through comparisons with the secondary dataset and multiple testing corrections, we found a negative association between the class Actinobacteria (OR=0.992886277, p-value = 0.003) and the likelihood of OA occurrence. Notably, knee osteoarthritis (KOA) and hip osteoarthritis (HOA) had a strong negative correlation (OR = 0.927237553/0.892581219). Our analysis suggests that BMR significantly mediates the causal pathway from Actinobacteria to OA, with a mediated effect of 2.59%. Additionally, BMR mediates 3.98% of the impact in the path from the order Bifidobacteriales and the family Bifidobacteriaceae to OA. Besides these findings, our reverse analysis did not indicate any significant effect of OA on gut microbiota or BMR. Conclusion: Our research results indicate that an increase in the abundance of specific gut microbial taxa is associated with a reduced incidence of OA, and BMR levels mediate this causal relationship. Further large-scale randomized controlled trials are necessary to validate the causal impact of gut microbiota on the risk of OA. This study provides new insights into the potential prevention of OA by modulating the gut microbiota.

Females adopt sexual catalepsy to facilitate mating.

Theory predicts that males and females of dioecious species typically engage in an evolutionary sexual conflict over the frequency and choice of mating partner. Female sexual cannibalism, a particularly dramatic illustration of this conflict, is widespread in certain animal taxa including spiders. Nevertheless, females of some funnel weaving spiders that are generally aggressive to conspecifics enter a cataleptic state after male courtship, ensuring the males can mate without risk of attack. In this study, we demonstrated that the physical posture and duration, metabolites, and central neurotransmitters of females of Aterigena aculeata in sexual catalepsy closely resemble females in thanatosis but are distinct from those in anesthesia, indicating that the courted females feign death to eliminate the risk of potentially aggressive responses and thereby allow preferred males to mate. Unlike the taxonomically widespread thanatosis, which generally represents a deceptive visual signal that acts against the interest of the receivers, sexual catalepsy of females in the funnel weaving spiders may deliver a sexual-receptive signal to the courting males and thereby benefit both the signal senders and receivers. Therefore, sexual catalepsy in A. aculeata may not reflect a conflict but rather a confluence of interest between the sexes.