Associations between impulsivity and fecal microbiota in individuals abstaining from methamphetamine.

INTRODUCTION: Methamphetamine (MA) abuse is a major public problem, and impulsivity is both a prominent risk factor and a consequence of addiction. Hence, clarifying the biological mechanism of impulsivity may facilitate the understanding of addiction to MA. The microbiota-gut-brain axis was suggested to underlie a biological mechanism of impulsivity induced by MA. METHODS: We therefore recruited 62 MA addicts and 50 healthy controls (HCs) to investigate the alterations in impulsivity and fecal microbiota and the associations between them in the MA group. Thereafter, 25 MA abusers who abstained from MA for less than 3 months were followed up for 2 months to investigate the relationship between impulsivity and microbiota as abstinence became longer. 16S rRNA sequencing was conducted for microbiota identification. RESULTS: Elevated impulsivity and dysbiosis characterized by an increase in opportunistic pathogens and a decrease in probiotics were identified in MA abusers, and both the increased impulsivity and disrupted microbiota tended to recover after longer abstinence from MA. Impulsivity was related to microbiota, and the effect of MA abuse on impulsivity was mediated by microbiota. CONCLUSION: Our findings potentially highlighted the importance of abstention and implicated the significant role of the microbiota-gut-brain axis in the interrelationship between microbiota and behaviors, as well as the potential of microbiota as a target for intervention of impulsivity.

The gut microbiota as a potential biomarker for methamphetamine use disorder: evidence from two independent datasets.

Background: Methamphetamine use disorder (MUD) poses a considerable public health threat, and its identification remains challenging due to the subjective nature of the current diagnostic system that relies on self-reported symptoms. Recent studies have suggested that MUD patients may have gut dysbiosis and that gut microbes may be involved in the pathological process of MUD. We aimed to examine gut dysbiosis among MUD patients and generate a machine-learning model utilizing gut microbiota features to facilitate the identification of MUD patients. Method: Fecal samples from 78 MUD patients and 50 sex- and age-matched healthy controls (HCs) were analyzed by 16S rDNA sequencing to identify gut microbial characteristics that could help differentiate MUD patients from HCs. Based on these microbial features, we developed a machine learning model to help identify MUD patients. We also used public data to verify the model; these data were downloaded from a published study conducted in Wuhan, China (with 16 MUD patients and 14 HCs). Furthermore, we explored the gut microbial features of MUD patients within the first three months of withdrawal to identify the withdrawal period of MUD patients based on microbial features. Results: MUD patients exhibited significant gut dysbiosis, including decreased richness and evenness and changes in the abundance of certain microbes, such as Proteobacteria and Firmicutes. Based on the gut microbiota features of MUD patients, we developed a machine learning model that demonstrated exceptional performance with an AUROC of 0.906 for identifying MUD patients. Additionally, when tested using an external and cross-regional dataset, the model achieved an AUROC of 0.830. Moreover, MUD patients within the first three months of withdrawal exhibited specific gut microbiota features, such as the significant enrichment of Actinobacteria. The machine learning model had an AUROC of 0.930 for identifying the withdrawal period of MUD patients. Conclusion: In conclusion, the gut microbiota is a promising biomarker for identifying MUD and thus represents a potential approach to improving the identification of MUD patients. Future longitudinal studies are needed to validate these findings.

Sex effects on differentiating patients with major depressive disorder from bipolar disorder in depressive state: A fMRI study with follow-up.

BACKGROUND: Bipolar disorder (BD) is difficult to discriminate from major depressive disorder (MDD) before the appearance of mania or hypomania. This study was designed to identify whether patients with MDD and those who converted to BD are distinguishable using dynamic amplitude low-frequency fluctuations (dALFF) and describe the sex effects on the identification of the two disorders. METHODS: We compared the dALFF values of 35 BD patients who converted from MDD during the 2-year follow-up, 99 MDD patients, and 130 healthy controls (HCs) using two-way ANOVA. Pearson's correlation was used to compare dALFF in dysfunctional brain regions and clinical characteristics. RESULTS: A main effect of diagnosis was discovered in the frontal and occipital gyrus. For the main effect of sex, both the left middle occipital gyrus and the medial part of the superior frontal gyrus had higher dALFF values in males compared to females. An interaction of sex and diagnosis effect was observed in the right precentral gyrus. Male MDD patients exhibited a higher dALFF value than male BD patients. Additionally, we discovered a higher dALFF value in females than in males in BD patients. WCST scores were positively associated with dALFF values in the frontal and occipital gyrus in MDD patients. Meanwhile, dALFF values in the occipital gyrus positively correlated with WCST in female MDD patients only. LIMITATION: Most of the participants were on medication and the sample size was small. CONCLUSIONS: Our study is the first to find the non-neglectable role of sex effects in differentiating BD and MDD at an early stage.

Functional and structural alterations in different durations of untreated illness in the frontal and parietal lobe in major depressive disorder.

Major depressive disorder (MDD) is one of the most disabling illnesses that profoundly restricts psychosocial functions and impairs quality of life. However, the treatment rate of MDD is surprisingly low because the availability and acceptability of appropriate treatments are limited. Therefore, identifying whether and how treatment delay affects the brain and the initial time point of the alterations is imperative, but these changes have not been thoroughly explored. We investigated the functional and structural alterations of MDD for different durations of untreated illness (DUI) using regional homogeneity (ReHo) and voxel-based morphometry (VBM) with a sample of 125 treatment-naïve MDD patients and 100 healthy controls (HCs). The MDD patients were subgrouped based on the DUI, namely, DUI ≤ 1 M, 1 < DUI ≤ 6 M, 6 < DUI ≤ 12 M, and 12 < DUI ≤ 48 M. Subgroup comparison (MDD with different DUIs) was applied to compare ReHo and grey matter volume (GMV) extracted from clusters of regions with significant differences (the pooled MDD patients relative to HCs). Correlations and mediation effects were analysed to estimate the relationships between the functional and structural neuroimaging changes and clinical characteristics. MDD patients exhibited decreased ReHo in the left postcentral gyrus and precentral gyrus and reduced GMV in the left middle frontal gyrus and superior frontal gyrus relative to HCs. The initial functional abnormalities were detected after being untreated for 1 month, whereas this duration was 3 months for GMV reduction. Nevertheless, a transient increase in ReHo was observed after being untreated for 3 months. No significant differences were discovered between HCs and MDD patients with a DUI less than 1 month or among MDD patients with different DUIs in either ReHo or GMV. Longer DUI was related to reduced ReHo with GMV as mediator in MDD patients. We identified disassociated functional and anatomical alterations in treatment-naïve MDD patients at different time points in distinct brain regions at the early stage of the disease. Additionally, we also discovered that GMV mediated the relationship between a longer DUI and diminished ReHo in MDD patients, disclosing the latent deleterious and neuro-progressive implications of DUI on both the structure and function of the brain and indicating the necessity of early treatment of MDD.

The aberrant dynamic amplitude of low-frequency fluctuations in melancholic major depressive disorder with insomnia.

Background: Insomnia is considered one of the manifestations of sleep disorders, and its intensity is linked to the treatment effect or suicidal thoughts. Major depressive disorder (MDD) is classified into various subtypes due to heterogeneous symptoms. Melancholic MDD has been considered one of the most common subtypes with special sleep features. However, the brain functional mechanisms in melancholic MDD with insomnia remain unclear. Materials and methods: Melancholic MDD and healthy controls (HCs, n = 46) were recruited for the study. Patients were divided into patients with melancholic MDD with low insomnia (mMDD-LI, n = 23) and patients with melancholic MDD with high insomnia (mMDD-HI, n = 30), according to the sleep disturbance subscale of the 17-item Hamilton Depression Rating Scale. The dynamic amplitude of low-frequency fluctuation was employed to investigate the alterations of brain activity among the three groups. Then, the correlations between abnormal dALFF values of brain regions and the severity of symptoms were investigated. Results: Lower dALFF values were found in the mMDD-HI group in the right middle temporal gyrus (MTG)/superior temporal gyrus (STG) than in the mMDD-LI (p = 0.014) and HC groups (p < 0.001). Melancholic MDD groups showed decreased dALFF values than HC in the right middle occipital gyri (MOG)/superior occipital gyri (SOG), the right cuneus, the bilateral lingual gyrus, and the bilateral calcarine (p < 0.05). Lower dALFF values than HC in the left MOG/SOG and the left cuneus in melancholic MDD groups were found, but no significant difference was found between the mMDD-LI group and HC group (p = 0.079). Positive correlations between the dALFF values in the right MTG/STG and HAMD-SD scores (the sleep disturbance subscale of the HAMD-17) in the mMDD-HI group (r = 0.41, p = 0.042) were found. In the pooled melancholic MDD, the dALFF values in the right MOG/SOG and the right cuneus (r = 0.338, p = 0.019), the left MOG/SOG and the left cuneus (r = 0.299, p = 0.039), and the bilateral lingual gyrus and the bilateral calcarine (r = 0.288, p = 0.047) were positively correlated with adjusted HAMD scores. Conclusion: The occipital cortex may be related to depressive symptoms in melancholic MDD. Importantly, the right MTG/STG may play a critical role in patients with melancholic MDD with more severe insomnia.

Altered dynamic amplitude of low-frequency fluctuation between bipolar type I and type II in the depressive state.

BACKGROUND: Bipolar disorder is a chronic and highly recurrent mental disorder that can be classified as bipolar type I (BD I) and bipolar type II (BD II). BD II is sometimes taken as a milder form of BD I or even doubted as an independent subtype. However, the fact that symptoms and severity differ in patients with BD I and BD II suggests different pathophysiologies and underlying neurobiological mechanisms. In this study, we aimed to explore the shared and unique functional abnormalities between subtypes. METHODS: The dynamic amplitude of low-frequency fluctuation (dALFF) was performed to compare 31 patients with BD I, 32 with BD II, and 79 healthy controls (HCs). Global dALFF was calculated using sliding-window analysis. Group differences in dALFF among the 3 groups were compared using analysis of covariance (ANCOVA), with covariates of age, sex, years of education, and mean FD, and Bonferroni correction was applied for post hoc analysis. Pearson and Spearman's correlations were conducted between clusters with significant differences and clinical features in the BD I and BD II groups, after which false error rate (FDR) was used for correction. RESULTS: We found a significant decrease in dALFF values in BD patients compared with HCs in the following brain regions: the bilateral-side inferior frontal gyrus (including the triangular, orbital, and opercular parts), inferior temporal gyrus, the medial part of the superior frontal gyrus, middle frontal gyrus, anterior cingulum, insula gyrus, lingual gyrus, calcarine gyrus, precuneus gyrus, cuneus gyrus, left-side precentral gyrus, postcentral gyrus, inferior parietal gyrus, superior temporal pole gyrus, middle temporal gyrus, middle occipital gyrus, superior occipital gyrus and right-side fusiform gyrus, parahippocampal gyrus, hippocampus, middle cingulum, orbital part of the medial frontal gyrus and superior frontal gyrus. Unique alterations in BD I were observed in the right-side supramarginal gyrus and postcentral gyrus. In addition, dALFF values in BD II were significantly higher than those in BD I in the right superior temporal gyrus and middle temporal gyrus. The variables of dALFF correlated with clinical characteristics differently according to the subtypes, but no correlations survived after FDR correction. LIMITATIONS: Our study was cross-sectional. Most of our patients were on medication, and the sample was limited. CONCLUSIONS: Our findings demonstrated neurobiological characteristics of BD subtypes, providing evidence for BD II as an independent existence, which could be the underlying explanation for the specific symptoms and/or severity and point to potential biomarkers for the differential diagnosis of bipolar subtypes.

Platelet-derived extracellular vesicles promote the migration and invasion of rheumatoid arthritis fibroblast-like synoviocytes via CXCR2 signaling.

Platelet-derived extracellular vesicles (PEVs), which are generated from the plasma membrane during platelet activation, may be involved in the inflammatory processes of rheumatoid arthritis (RA). The motility of RA fibroblast-like synoviocytes (RA-FLS) plays a key role in the development of synovial inflammation and joint erosion. However, the effects of PEVs on the motility of RA-FLS remain unclear. Thus, the present study aimed to investigate the active contents and potential molecular mechanisms underlying the role of PEVs in regulating the migration and invasion of RA-FLS. The results demonstrated that PEVs contain certain chemokines associated with cell migration and invasion, including C-C motif chemokine ligand 5, C-X-C motif chemokine ligand (CXCL)4 and CXCL7. Furthermore, SB225002, an antagonist of C-X-C motif chemokine receptor 2 (CXCR2; a CXCL7 receptor), partially prevented the migration and invasion of RA-FLS induced by PEVs, suggesting that PEVs may activate a CXCR2-mediated signaling pathway in RA-FLS. In addition, SB225002 antagonized the phosphorylation of IκB and NF-κB in RA-FLS induced by PEVs. Taken together, the results of the present study suggested that PEVs may promote the migration and invasion of RA-FLS by activating the NF-κB pathway mediated by the CXCR2 signaling pathway.

Knockdown of YAP/TAZ Inhibits the Migration and Invasion of Fibroblast Synovial Cells in Rheumatoid Arthritis by Regulating Autophagy.

The purpose of this study was to investigate the effect of knockdown of the yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) on the migration and invasion of the rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) and to preliminarily elucidate the mechanisms between YAP/TAZ and autophagy in the migration and invasion of RA-FLS. RA-FLS stable knockdown of YAP or TAZ was successfully established by using lentiviral-mediated gene knockdown techniques. Wound healing assay and Transwell assay were used to evaluate the effect of knockdown of YAP or TAZ on the migration and invasion of RA-FLS. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and western blotting assays were performed to examine the expression of indicated genes. The results showed that YAP and TAZ were upregulated in RA-FLS, and knockdown of YAP or TAZ inhibited the migration and invasion, reduced the expression of N-cadherin and Vimentin, and increased the accumulation of E-cadherin and ß-catenin in RA-FLS. Our results also demonstrated that knockdown of YAP or TAZ promoted autophagy which increased the accumulation of LC3B-II and ULK1 and decreased the amount of SQSTM1/p62 in RA-FLS. Furthermore, our data displayed that inhibition of autophagy either with 3-MA or CQ can partially reverse the decrease of migration and invasion induced by YAP and TAZ knockdown in RA-FLS. Our experiments preliminarily revealed that YAP/TAZ and autophagy play important roles in the migration and invasion of RA-FLS, which might provide novel targets for the treatment of RA.

Monopolar spindle-one-binder protein 2 regulates the activity of large tumor suppressor/yes-associated protein to inhibit the motility of SMMC-7721 hepatocellular carcinoma cells.

Accumulating evidence implicates monopolar spindle-one-binder protein (MOB)2 as an inhibitor of nuclear-Dbf2-related kinase (NDR) by competing with MOB1 for interaction with NDR1/2. NDR/large tumor suppressor (LATS) kinases may function similarly to yes-associated protein (YAP) kinases and be considered as members of the Hippo core cassette. MOB2 appears to serve roles in cell survival, cell cycle progression, responses to DNA damage and cell motility. However, the underlying mechanisms involved remain unclarified. In the present study, it was demonstrated that the knockout of MOB2 by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 promoted migration and invasion, induced phosphorylation of NDR1/2 and decreased phosphorylation of YAP in SMMC-7721 cells when compared with the blank vector-transduced cells. By contrast, the overexpression of MOB2 resulted in the opposite results. Mechanistically, MOB2 regulated the alternative interaction of MOB1 with NDR1/2 and LATS1, which resulted in increased phosphorylation of LATS1 and MOB1 and thereby led to the inactivation of YAP and consequently inhibition of cell motility. The results of the present study provide evidence of MOB2 serving a positive role in LATS/YAP activation by activating the Hippo signaling pathway.

Immediate early response protein 2 regulates hepatocellular carcinoma cell adhesion and motility via integrin ß1-mediated signaling pathway.

Human immediate early response 2 (IER2) has been reported to function as a potential transcriptional factor or transcriptional co­activator and seems to play a pivotal role in tumor cell motility and metastasis, however, its role and underlying mechanisms in hepatocellular carcinoma (HCC) remain unknown. Herein, we demonstrated that overexpression of IER2 in HCC cells increased cell adhesion to fibronectin, migration and invasion, whereas knockdown of IER2 displayed the opposite effects. In agreement with this phenotype, IER2 expression was positively correlated with the metastatic potential and integrin ß1 (ITGB1) expression in HCC cell lines. Moreover, we demonstrated a critical role for IER2 in regulation of HCC cell­extracellular matrix (ECM) adhesion and motility by the transcriptionally promoted ITGB1. Furthermore, we showed that ITGB1­focal adhesion kinase (FAK)­Src­paxillin signal pathway activated by IER2 may contribute to the HCC cell­ECM adhesion and motility. These results demonstrated that IER2 promoted HCC cell adhesion and motility probably by directly increasing ITGB1 expression and subsequently activating the ITGB1­FAK­Src­paxillin signal pathway.

Identification of immediate early response protein 2 as a regulator of angiogenesis through the modulation of endothelial cell motility and adhesion.

Human immediate early response 2 (IER2) has been characterized as a putative nuclear protein that functions as a transcription factor or transcriptional co­activator in the regulation of cellular responses, and may be involved in the regulation of tumor progression and metastasis. Data from our previous gene expression profile of the human microvascular endothelial cells during capillary morphogenesis showed a significant alteration of IER2 expression, suggesting that IER2 may participate in the regulation of the endothelial cell morphogenesis and angiogenesis. The aim of the present study was to investigate the role of IER2 in cell motility, cell­matrix adhesion and in vitro capillary­like structures formation of the human umbilical vein endothelium cells (HUVECs). IER2 was constitutively expressed in HUVECs, and lentiviral­mediated depletion of IER2 significantly reduced the cell motility, cell­matrix adhesion and capillary­like structures formation of HUVECs. Results also showed that depletion and overexpression of IER2 altered the actin cytoskeleton rearrangement in HUVECs. Furthermore, results from western blot analysis showed that the activity of the focal adhesion kinase (FAK) can be regulated by IER2. These results indicated that IER2 regulates endothelial cell motility, adhesion on collagen type I matrix and the capillary tube formation, as the result of the regulation of the actin cytoskeleton rearrangement presumably via a FAK­dependent mechanism.

miR-30c negatively regulates the migration and invasion by targeting the immediate early response protein 2 in SMMC-7721 and HepG2 cells.

miR-30c has been reported to act as a tumor suppressor and negatively regulate cancer metastasis by directly targeting metastasis associated genes; however, miR-30c has also been shown to promote the invasion of metastatic breast cancer cells, suggesting that miR-30c might be involved in cancer cell metastasis in different ways via targeting different genes. In this study, we demonstrated that over-expression and knockdown of immediate early response protein 2 (IER2) modulated the general capacity of the migration and invasion in hepatocellular carcinoma cell line SMMC-7721 and HepG2, whereas overexpression and knockdown of miR-30c decreased and promoted cell motility, respectively. Further studies revealed that miR-30c overexpression down-regulated the expression of IER2 protein but not its mRNA level, and miR-30c can directly target the 3' untranslated region (3'UTR) of IER2, and subsequently reducing its expression. Moreover, we also showed that suppression of cell motility by miR-30c was partially rescued by IER2 re-expression. Our results indicated that miR-30c may function as a negative regulator in cell motility, with IER2 as a direct and functional target in SMMC-7721 and HepG2 cells.