A Conserved Intramolecular Ion-Pair Plays a Critical but Divergent Role in Regulation of Dimerization and Transport Function among the Monoamine Transporters.

The monoamine transporters, including the serotonin transporter (SERT), dopamine transporter (DAT), and norepinephrine transporter (NET), are the therapeutic targets for the treatment of many neuropsychiatric disorders. Despite significant progress in characterizing the structures and transport mechanisms of these transporters, the regulation of their transport functions through dimerization or oligomerization remains to be understood. In the present study, we identified a conserved intramolecular ion-pair at the third extracellular loop (EL3) connecting TM5 and TM6 that plays a critical but divergent role in the modulation of dimerization and transport functions among the monoamine transporters. The disruption of the ion-pair interactions by mutations induced a significant spontaneous cross-linking of a cysteine mutant of SERT and an increase in cell surface expression but with an impaired specific transport activity. On the other hand, similar mutations of the corresponding ion-pair residues in both DAT and NET resulted in an opposite effect on their oxidation-induced dimerization, cell surface expression, and transport function. Reversible biotinylation experiments indicated that the ion-pair mutations slowed down the internalization of SERT but stimulated the internalization of DAT. In addition, cysteine accessibility measurements for monitoring SERT conformational changes indicated that substitution of the ion-pair residues resulted in profound effects on the rate constants for cysteine modification in both the extracellular and cytoplasmatic substrate permeation pathways. Furthermore, molecular dynamics simulations showed that the ion-pair mutations increased the interfacial interactions in a SERT dimer but decreased it in a DAT dimer. Taken together, we propose that the transport function is modulated by the equilibrium between monomers and dimers on the cell surface, which is regulated by a potential compensatory mechanism but with different molecular solutions among the monoamine transporters. The present study provided new insights into the structural elements regulating the transport function of the monoamine transporters through their dimerization.

Unique Substrate Recognition and Sodium-Substrate Binding Stoichiometry in a Bacterial Serotonin Transporter, TuriSERT.

All resolved high-resolution structures of the transporters in the neurotransmitter sodium symporter (NSS) family revealed that the NSS members share common structural and mechanistic features for substrate and ion binding and transport. However, a recently reported bacterial orthologue of the human serotonin transporter (hSERT), TuriSERT, possesses a structural characteristic specific for amino acid substrate binding but does transport a biogenic amine. The unique structural feature of TuriSERT requires a novel configuration for coordinating its substrate and ions. In the present study, we characterized TuriSERT expressed in Escherichia coli cells with a fluorescent substrate by biochemical, structural, and pharmacological approaches. Substrate transport by TuriSERT requires Na+ but not Cl-. Replacement of Asp262 by asparagine renders TuriSERT Cl--dependent. Substitutions of the corresponding Na1 residues did not alter Na+ dependence on substrate transport, whereas the mutation of a Na2 site residue led to a loss of transport activity, suggesting that Na+ binds only to the Na2 site in TuriSERT. In addition, substitutions of several residues essential for recognizing 5-hydroxytryptamine (5-HT) in hSERT had little effect on 5-HT displacement potency in transport assay for TuriSERT. In contrast, mutations of the residues that are proposed to coordinate with 5-HT in our docking model dramatically reduced 5-HT displacement. Furthermore, our results indicated that all tested antidepressants showed a weak inhibitory effect on TuriSERT. The present study demonstrated the existence of a unique substrate binding site and 1:1 stoichiometry of sodium-substrate binding in TuriSERT, a novel structural finding for the NSS transporters.

Efficacy of Kegel exercises combined with electrical stimulation on the restoration of postpartum pelvic floor muscle function.

OBJECTIVE: To investigate the efficacy of Kegel exercises combined with electrical stimulation on the restoration of postpartum pelvic floor muscle (PFM) function. METHODS: Data of 120 parturients with full-term singleton pregnancy who delivered vaginally in the Guang'an People's Hospital were retrospectively analyzed, and the study subjects were grouped into a Kegel exercise group (n=40, receiving Kegel exercise alone), an electrical stimulation group (n=40, receiving electrical stimulation alone) and a combined group (n=40, receiving Kegel exercises combined with electrical stimulation) according to the treatments received. All three groups received intervention for 3 months. The overall response rates (ORRs) at 3 months, changes in PFM strength and vaginal pressure during treatment, the scores of International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF), the incontinence quality of life questionnaire (I-QOL), and the incidence rates of pelvic floor dysfunction (PFD) were evaluated in the three groups. RESULTS: ORR in the combined group (100.00%) was higher than that of the Kegel exercises group (87.50%) and the electrical stimulation group (85.00%) (P < 0.05). At 1, 3, and 6 months after intervention, the combined group was superior to the Kegel exercises and the electrical stimulation groups in systolic blood pressure (SBP) of pelvic floor, and the continuous SBP of type I and II muscle fibers (P < 0.05). After 6 months of follow-up, the scores of ICIQ-UI SF and I-QOL in the combined group were higher than those in the Kegel exercises and electrical stimulation groups (P < 0.05). The score of satisfaction in the combined group was higher than in Kegel exercises and electrical stimulation groups (P < 0.05). CONCLUSION: Kegel exercises combined with electrical stimulation have a good therapeutic effect on postpartum pelvic floor dysfunction, which can markedly improve PFM strength and vaginal pressure.

Retroperitoneal laparoscopic renorrhaphy for post-percutaneous nephrolithotomy hemorrhage: a case report.

Percutaneous nephrolithotomy is the preferred treatment for large renal calculi; however, postoperative hemorrhage is a dangerous complication. The three main causes of hemorrhage after percutaneous nephrolithotomy are pseudoaneurysms, arteriovenous fistulas, and arterial lacerations. The preferred treatment for acute hemorrhage is superselective angioembolization. However, in a few cases, angiography reveals no abnormal findings pertaining to hemorrhage. We herein present a clinical case of a 48-year-old man who presented with multiple complex right renal calculi and was managed with percutaneous nephrolithotomy in the prone position. Massive hemorrhage occurred 6 days postoperatively, and renal angiography was immediately performed. However, while the bleeding was still occurring, no extravasation was observed on renal angiography. We performed retroperitoneal laparoscopic renorrhaphy, which successfully stopped the bleeding and consequently preserved the kidney. We suggest that retroperitoneal laparoscopic renorrhaphy can be effective in patients who have undergone failed renal arterial embolization or are reluctant to undergo renal arterial embolization.

Jieduquyuziyin Prescription Suppresses Inflammatory Activity of MRL/lpr Mice and Their Bone Marrow-Derived Macrophages via Inhibiting Expression of IRAK1-NF-κB Signaling Pathway.

Jieduquyuziyin prescription (JP) has been used to treat systemic lupus erythematosus (SLE). Although the effectiveness of JP in the treatment of SLE has been clinically proven, the underlying mechanisms have yet to be completely understood. We observed the therapeutic actions of JP in MRL/lpr mice and their bone marrow-derived macrophages (BMDMs) and the potential mechanism of their inhibition of inflammatory activity. To estimate the effect of JP on suppressing inflammatory activity, BMDMs of MRL/lpr and MRL/MP mice were treated with JP-treated serum, and MRL/lpr mice were treated by JP for 8 weeks. Among them, JP and its treated serum were subjected to quality control, and BMDMs were separated and identified. The results showed that in the JP group of BMDMs stimulated by Lipopolysaccharide (LPS) in MRL/lpr mice, the secretion of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) reduced, and the expressions of Interleukin-1 receptor-associated kinase 1 (IRAK1) and its downstream nuclear factor κB (NF-κB) pathway decreased. Meanwhile, the alleviation of renal pathological damage, the decrease of urinary protein and serum anti-dsDNA contents, the inhibition of TNF-α level, and then the suppression of the IRAK1-NF-κB inflammatory signaling in the spleen and kidney, confirmed that the therapeutic effect of JP. These results demonstrated that JP could inhibit the inflammatory activity of MRL/lpr mice and their BMDMs by suppressing the activation of IRAK1-NF-κB signaling and was supposed to be a good choice for the treatment of SLE.

Role of identified noncoding RNA in erectile dysfunction.

Erectile dysfunction (ED) is a common male sexual dysfunction and is closely related to many risk factors such as age, chronic diseases and mental disorder. Phosphodiesterase type 5 inhibitor (PDE5i) is recommended as the first-line medicine in therapy, but up to 35% of patients fail to this treatment. Unfortunately, the pathogenesis of ED is still poorly understood. Hence, it has reached the state that researchers should seek for new candidate biomarkers or therapeutic targets. Recent studies have reported that noncoding RNAs (ncRNAs) such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are involved in the pathogenesis process of ED, even in stem cell therapy. In this review, we aim to summarise the mechanisms and functions of identified ncRNAs that are associated with ED.

Hypoxia-Induced Phenotypic Transformation of Corpus Cavernosum Smooth Muscle Cells After Cavernous Nerve Crush Injury by Down-Regulating P38 Mitogen-Activated Protein Kinase Expression.

INTRODUCTION: Cavernosal nerve (CN) injury is commonly caused by radical prostatectomy surgery, and it might directly lead to erectile dysfunction (ED). Currently, the role of mitogen-activated protein kinase (MAPK) family proteins in phenotypic transformation of corpus cavernosum smooth muscle cell (CCSMC) after CNs injury is poorly understood. AIM: To investigate the role of p38 MAPK in hypoxia-induced phenotypic transformation of CCSMCs after CN injury. METHODS: In total, 20 Sprague-Dawley rats (male and 8 weeks of age) were randomly divided into 2 groups, including a sham group and CNCI group. In the sham group, rats were sham-operated by identifying 2 CNs without causing direct damage to the CNs. In the CNCI group, rats were subjected to bilateral CN crush injury. CCSMCs were isolated from the normal corpus cavernosum tissues of the Sprague-Dawley rat and then cultured in 21% or 1% O2 concentration context for 48 hours. MAIN OUTCOME MEASURES: Intracavernous pressure/mean arterial pressure were analyzed to measure erectile response. The impact of hypoxia on penile pathology, as well as the expression of extracellular signal-regulated kinases, the c-Jun NH2-terminal kinase, and p38 MAPK, were analyzed. RESULTS: Compared with the sham group, the intracavernous pressure/mean arterial pressure rate and α-smooth muscle actin expression of CNCI group were decreased significantly (P = .0001; P = .016, respectively), but vimentin expression was significantly increased (P = .023). Phosphorylated p38 level in CNCI group was decreased significantly (P = .017; sham: 0.17 ± 0.005; CNCI: 0.14 ± 0.02). The CCSMCs in the normoxia group were long fusiform, whereas the morphology of CCSMCs in the hypoxia group became hypertrophic. After hypoxia for 48 hours, the expression of α-smooth muscle actin and phosphorylated p38 MAPK was decreased significantly (P = .01; P = .024, normoxia: 0.66 ± 0.18, hypoxia: 0.26 ± 0.08, respectively), and the expression of hypoxia-inducible factor-1α and collagen I was increased significantly in hypoxia group (P = .04; P = .012, respectively). CONCLUSIONS: Hypoxia induced the phenotypic transformation of CCSMCs after CNCI might be associated with the downregulation of phosphorylated p38 MAPK. Chen S, Huang X, Kong X, et al. Hypoxia-Induced Phenotypic Transformation of Corpus Cavernosum Smooth Muscle Cells After Cavernous Nerve Crush Injury by Down-Regulating p38 Mitogen-Activated Protein Kinase Expression. Sex Med 2019;7:433-440.

Roles of Identified Long Noncoding RNA in Diabetic Nephropathy.

Diabetes mellitus is the leading chronic disease in the world, and diabetic nephropathy (DN) as one of its complications could increase the mortality. The development of DN is associated to abnormal hemodynamic factors like cytokine networks and the intervention of metabolic risk factors like blood pressure, blood glucose, and blood lipid. However, the pathogenesis of DN is still poorly understood. Although glucose-lowering drugs and insulins have significant effects on blood glucose, the fluctuation of blood glucose or other risk factors could continuously damage the kidney. Recent studies reported that the progression of DN is closely related to the expression of long noncoding RNA (lncRNA), which is important for the early diagnosis and targeted intervention of DN. In this review, we briefly summarize the published studies on the functions and potential mechanism of reported lncRNA in the regulation of DN.

[Inhibitory effect of salidroside on H2O2-induced down-regulation of Cx43 expression in corpus cavernosum smooth muscle cells in rats].

OBJECTIVE: To explore the regulatory effect of salidroside on H2O2-induced decrease in the expression of the connexin43 (Cx43) protein in corpus cavernosum smooth muscle cells (CCSMC). METHODS: Rat CCSMCs were isolated, primarily cultured in vitro and identified by immunocytochemical assay. The optimum concentration of H2O2 for intervention was determined by detecting its effect on the viability of the CCSMCs and used in the treatment of the CCSMCs for different lengths of time, and meanwhile salidroside was applied at 16 µg/ml (low dose) or 64 µg/ml (high dose) for intervention. Finally, the expressions of the Cx43 protein in the CCSMCs of different groups of rats were determined by Western blot. RESULTS: The CCSMCs grew normally, with a positive rate of over 90%. At 1, 2 and 4 hours of treatment with H2O2 at the optimum concentration of 200 µmol/L, the expression of Cx43 in the CCSMCs was significantly decreased as compared with that in the blank control group (P < 0.01), even more significantly at 4 hours than at 1 and 2 (P < 0.01). Intervention with high-dose salidroside, however, markedly inhibited the down-regulation of the Cx43 expression (P < 0.05), which showed no statistically significant difference from that in the normal control group (P = 0.322 2). CONCLUSIONS: Salidroside can suppress H2O2-induced decrease in the expression of the Cx43 protein in rat CCSMCs.

[MAPK signaling pathway and erectile dysfunction].

The MAPK signaling pathway plays a key role in the differentiation, proliferation and apoptosis of cells, and its family members mainly include extracellular signal-regulated kinase (ERK), stress-activated protein kinase (JNK), and p38 mitogen-activated protein kinase (p38MAPK). Recent studies have shown that the ERK, JNK and p38MAPK signaling pathways are closely associated with the development and progression of erectile dysfunction (ED). This review focuses on the correlation between the MAPK signaling pathway and ED.