The excitatory transmission from basolateral nuclues of amygdala to nucleus accumbens shell regulates propofol self-administration through AMPA receptors

Propofol addictive properties have been demonstrated in humans and rats. The glutamatergic transmission from basolateral nucleus of amygdala (BLA) to the nucleus accumbens (NAc) modulates reward-seeking behaviour; especially, NAc shell (NAsh) is implicated in reward-seeking response. Previous studies indicated the interactions between AMPA receptors (AMPARs) and dopamine D1 receptor (D1R) in NAc mediated drug addiction, but whether the circuit of BLA-to-NAsh and AMPARs regulate propofol addiction remains unclear. We trained adult male Sprague-Dawley rats for propofol self-administration to examine the changes of action potentials (APs) and spontaneous excitatory postsynaptic currents (sEPSCs) in the NAsh. Thereafter, optogenetic stimulation with adeno-associated viral vectors microinjections in BLA was used to explore the effect of BLA-to-NAsh on propofol self-administration behaviour (1.7 mg/kg/injection). The pretreatment effects with NBQX (0.25-1.0 μg/0.3 μl/site) or vehicle in the NAsh on propofol self-administration behaviour, the expressions of AMPARs subunits and D1R/ERK/CREB signalling pathway in the NAc were detected. The results showed that the number of APs, amplitude and frequency of sEPSCs were enhanced in propofol self-administrated rats. Propofol self-administration was inhibited in the NpHR3.0-EYFP group, but in the ChR2-EYFP group, there was a promoting effect, which could be weakened by NBQX pretreatment. NBQX pretreatment also significantly decreased the expressions of GluA2 subunit and D1R in the NAc but did not change the expressions of GluA1 and ERK/CREB signalling pathway. The evidence supports a vital role of BLA-to-NAsh circuit in regulating propofol self-administration and suggests this central reward processing may function through the interaction between AMPARs and D1R in the NAsh.

Sevoflurane but not propofol enhances ovarian cancer cell biology through regulating cellular metabolic and signaling mechanisms

Perioperative risk factors, including the choice of anesthetics, may influence ovarian cancer recurrence after surgery. Inhalational anesthetic sevoflurane and intravenous agent propofol might affect cancer cell metabolism and signaling, which, in turn, may influence the malignancy of ovarian cancer cells. The different effects between sevoflurane and propofol on ovarian cancer cell biology and underlying mechanisms were studied. Cultured ovarian cancer cells were exposed to 2.5% sevoflurane, 4 μg/mL propofol, or sham condition as the control for 2 h followed by 24-h recovery. Glucose transporter 1 (GLUT1), mitochondrial pyruvate carrier 1 (MPC1), glutamate dehydrogenase 1 (GLUD1), pigment epithelium-derived factor (PEDF), p-Erk1/2, and hypoxia-inducible factor 1-alpha (HIF-1α) expressions were determined with immunostaining and/or Western blot. Cultured media were collected for 1H-NMR spectroscopy-based metabolomics analysis. Principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) were used to analyze metabolomics data. Sevoflurane increased the GLUT1, MPC1, GLUD1, p-Erk1/2, and HIF-1α expressions but decreased the PEDF expression relative to the controls. In contrast to sevoflurane, propofol decreased GLUT1, MPC1, GLUD1, p-Erk1/2, and HIF-1α but increased PEDF expression. Sevoflurane increased metabolite isopropanol and decreased glucose and glutamine energy substrates in the media, but the opposite changes were found after propofol treatment. Our data indicated that, unlike the pro-tumor property of sevoflurane, propofol negatively modulated PEDF/Erk/HIF-1α cellular signaling pathway and inhibited ovarian cancer metabolic efficiency and survival, and hence decreased malignancy. The translational value of this work warrants further study. • Sevoflurane promoted but propofol inhibited ovarian cancer cell biology. • Sevoflurane upregulated but propofol downregulated the GLUT1, MPC1, and GLUD1 expressions of ovarian cancer cells. • Sevoflurane enhanced but propofol inhibited ovarian cancer cellular glucose. metabolism and glutaminolysis. • Sevoflurane downregulated PEDF but upregulated the Erk pathway and HIF-1α, while propofol had the adverse effects on ovarian cancer cells.

Isoflurane and Sevoflurane Induce Cognitive Impairment in Neonatal Rats by Inhibiting Neural Stem Cell Development Through Microglial Activation, Neuroinflammation, and Suppression of VEGFR2 Signaling Pathway

Inhaled anesthetics are known to induce neurotoxicity in the developing brains of rodents, although the mechanisms are not well understood. The aim of this study was to elucidate the molecular mechanisms underlying anesthetics-induced neurodevelopmental toxicity by VEGF receptor 2 (VEGFR2) through the interaction between microglia and neural stem cells (NSCs) in postnatal day 7 (P7) rats. Cognitive function of P7 rats exposed to isoflurane and sevoflurane were assessed using Morris Water Maze and T maze tests. We also evaluated the expression levels of NSC biomarkers (Nestin and Sox2), microglia biomarker (CD11b or or IBA1), pro-inflammatory cytokines (IL-6 and TNF-α), and VEGFR2 using western blotting and immunohistochemistry in the brains of control and anesthesia-treated rats. We found spatial learning and working memory was impaired 2 weeks after anesthetics exposure in rats. Isoflurane induced stronger and more prolonged neurotoxicity than sevoflurane. However, cognitive functions were recovered 6 weeks after anesthesia. Isoflurane and sevoflurane decreased the levels of Nestin, Sox2, and p-VEGFR2, activated microglia, decreased the number of NSCs and reduced neurogenesis and the proliferation of NSCs, and increased the levels of IL-6, TNF-α, and CD11b. Our results suggested that isoflurane and sevoflurane induced cognitive impairment in rats by inhibiting NSC development and neurogenesis via microglial activation, neuroinflammation, and suppression of VEGFR2 signaling pathway.

The role of the vagus nerve on dexmedetomidine promoting survival and lung protection in a sepsis model in rats

BACKGROUND

Sepsis often results in acute lung injury (ALI). Dexmedetomidine (Dex) was reported to protect cells and organs due to its direct cellular effects. This study aims to investigate the role of vagus nerves on Dex induced lung protection in lipopolysaccharide (LPS)-induced ALI rats.

METHODS

The bilateral cervical vagus nerve of male Sprague-Dawley rats was sectioned or just exposed as sham surgery. After LPS administration, Dex antagonist yohimbine (YOH) and/or Dex was injected intraperitoneally to rats with or without vagotomy. The severity of ALI was determined with survival curve analysis and lung pathological scores. The plasma concentrations of interleukin 1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), catecholamine and acetylcholine were measured with enzyme-linked immunosorbent assay.

RESULTS

The median survival time of LPS-induced ALI rats was prolonged by Dex (22 h, 95% CI, [24.46, 92.20]) vs. 14 h, 95% CI, [14.60, 89.57] of the LPS control group, P < 0.05), and the ALI score was reduced by Dex (6.5, 95% CI, [5.23, 8.10] vs. 11.5, 95% CI, [10.23, 13.10] in the LPS group, P < 0.01). However, these protective effects were significantly decreased by either YOH administration or vagotomy. Dex decreased LPS-induced IL-1β, TNF-α, and catecholamine but increased acetylcholine in blood serum; these effects of Dex was partially abolished by vagotomy.

CONCLUSIONS

Our data suggested that Dex increased vagal nerve tone that partially contributed to its anti-inflammatory and lung-protective effects. The indirect anti-inflammation and direct cytoprotection of Dex are likely through high vagal nerve tone and α₂-adrenoceptor activation, respectively.

Effect of Regional vs General Anesthesia on Incidence of Postoperative Delirium in Older Patients Undergoing Hip Fracture Surgery: The RAGA Randomized Trial

IMPORTANCE

In adults undergoing hip fracture surgery, regional anesthesia may reduce postoperative delirium, but there is uncertainty about its effectiveness.

OBJECTIVE

To investigate, in older adults undergoing surgical repair for hip fracture, the effects of regional anesthesia on the incidence of postoperative delirium compared with general anesthesia.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, allocation-concealed, open-label, multicenter clinical trial of 950 patients, aged 65 years and older, with or without preexisting dementia, and a fragility hip fracture requiring surgical repair from 9 university teaching hospitals in Southeastern China. Participants were enrolled between October 2014 and September 2018; 30-day follow-up ended November 2018.

INTERVENTIONS

Patients were randomized to receive either regional anesthesia (spinal, epidural, or both techniques combined with no sedation; n = 476) or general anesthesia (intravenous, inhalational, or combined anesthetic agents; n = 474).

MAIN OUTCOMES AND MEASURES

Primary outcome was incidence of delirium during the first 7 postoperative days. Secondary outcomes analyzed in this article include delirium severity, duration, and subtype; postoperative pain score; length of hospitalization; 30-day all-cause mortality; and complications.

RESULTS

Among 950 randomized patients (mean age, 76.5 years; 247 [26.8%] male), 941 were evaluable for the primary outcome (6 canceled surgery and 3 withdrew consent). Postoperative delirium occurred in 29 (6.2%) in the regional anesthesia group vs 24 (5.1%) in the general anesthesia group (unadjusted risk difference [RD], 1.1%; 95% CI, -1.7% to 3.8%; P = .48; unadjusted relative risk [RR], 1.2 [95% CI, 0.7 to 2.0]; P = .57]). Mean severity score of delirium was 23.0 vs 24.1, respectively (unadjusted difference, -1.1; 95% CI, -4.6 to 3.1). A single delirium episode occurred in 16 (3.4%) vs 10 (2.1%) (unadjusted RD, 1.1%; 95% CI, -1.7% to 3.9%; RR, 1.6 [95% CI, 0.7 to 3.5]). Hypoactive subtype in 11 (37.9%) vs 5 (20.8%) (RD, 11.5; 95% CI, -11.0% to 35.7%; RR, 2.2 [95% CI, 0.8 to 6.3]). Median worst pain score was 0 (IQR, 0 to 20) vs 0 (IQR, 0 to 10) (difference 0; 95% CI, 0 to 0). Median length of hospitalization was 7 days (IQR, 5 to 10) vs 7 days (IQR, 6 to 10) (difference 0; 95% CI, 0 to 0). Death occurred in 8 (1.7%) vs 4 (0.9%) (unadjusted RD, -0.8%; 95% CI, -2.2% to 0.7%; RR, 2.0 [95% CI, 0.6 to 6.5]). Adverse events were reported in 106 episodes in the regional anesthesia group and 102 in the general anesthesia group; the most frequently reported adverse events were nausea and vomiting (47 [44.3%] vs 34 [33.3%]) and postoperative hypotension (13 [12.3%] vs 10 [9.8%]).

CONCLUSIONS AND RELEVANCE

In patients aged 65 years and older undergoing hip fracture surgery, regional anesthesia without sedation did not significantly reduce the incidence of postoperative delirium compared with general anesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02213380.

The Antagonism of Corticotropin-Releasing Factor Receptor-1 in Brain Suppress Stress-Induced Propofol Self-Administration in Rats

Propofol addiction has been detected in humans and rats, which may be facilitated by stress. Corticotropin-releasing factor acts through the corticotropin-releasing factor (CRF) receptor-1 (CRF1R) and CRF2 receptor-2 (CRF2R) and is a crucial candidate target for the interaction between stress and drug abuse, but its role on propofol addiction remains unknown. Tail clip stressful stimulation was performed in rats to test the stress on the establishment of the propofol self-administration behavioral model. Thereafter, the rats were pretreated before the testing session at the bilateral lateral ventricle with one of the doses of antalarmin (CRF1R antagonist, 100–500 ng/site), antisauvagine 30 (CRF2R antagonist, 100–500 ng/site), and RU486 (glucocorticoid receptor antagonist, 100–500 ng/site) or vehicle. The dopamine D1 receptor (D1R) in the nucleus accumbens (NAc) was detected to explore the underlying molecular mechanism. The sucrose self-administration establishment and maintenance, and locomotor activities were also examined to determine the specificity. We found that the establishment of propofol self-administration was promoted in the tail clip treated group (the stress group), which was inhibited by antalarmin at the dose of 100–500 ng/site but was not by antisauvagine 30 or RU486. Accordingly, the expression of D1R in the NAc was attenuated by antalarmin, dose-dependently. Moreover, pretreatments fail to change sucrose self-administration behavior or locomotor activities. This study supports the role of CRF1R in the brain in mediating the central reward processing through D1R in the NAc and provided a possibility that CRF1R antagonist may be a new therapeutic approach for the treatment of propofol addiction.

Apoptosis and necroptosis occur in the different brain regions of hippocampus in a rat model of hypoxia asphyxia

AIM OF THE STUDY

Hypoxic-ischemic encephalopathy (HIE) is a major cause of newborn brain injury. Apoptosis and necroptosis are two forms of cell death which may occur in HIE but reported data are yet limited. This study investigates the expression of receptor interacting protein kinase (RIPK) 1 and 3, and caspase3, the key modulators of necroptosis and apoptosis, respectively, in a model of HIE to determine whether both forms of cell death occur in the corresponding brain regions.

MATERIALS AND METHODS

Postneonatal day 7 Sprague-Dawley rats were subjected to right carotid artery ligation followed by hypoxia or subjected to skin incision under surgical anesthesia without ligation and hypoxia. Neuroglioma (H4) cell was cultured and subjected to 24 h hypoxic insults. Necrostatin-1, a RIPK1 inhibitor, was administered in both in vivo and in vitro settings before insult.

RESULTS

After hypoxic-ischemic insults, both RIPK1 and RIPK3 expression were significantly increased in the region of hippocampal dentate gyrus in the injurious hemisphere. However, cleaved caspase3 was significantly increased in the hippocampal cornu ammonis 1 region in the injurious hemisphere. After hypoxic insults, RIPK1 and RIPK3 expression was also found in H4 cells. In addition, it was identified that the increased RIPK1 and RIPK3 can be inhibited by necrostatin-1 in both in vivo and in vitro.

CONCLUSIONS

These data indicated that apoptosis and necroptosis occur in different brain regions of hippocampus in a model of HIE which may suggest that strategies to prevent each form of neuronal death is valuable to be developed.

Single-cell RNA sequencing identifies molecular targets associated with poor in vitro maturation performance of oocytes collected from ovarian stimulation

STUDY QUESTION

What is the transcriptome signature associated with poor performance of rescue IVM (rIVM) oocytes and how can we rejuvenate them?

SUMMARY ANSWER

The GATA-1/CREB1/WNT signalling axis was repressed in rIVM oocytes, particularly those of poor quality; restoration of this axis may produce more usable rIVM oocytes.

WHAT IS KNOWN ALREADY

rIVM aims to produce mature oocytes (MII) for IVF through IVM of immature oocytes collected from stimulated ovaries. It is not popular due to limited success rate in infertility treatment. Genetic aberrations, cellular stress and the absence of cumulus cell support in oocytes could account for the failure of rIVM.

STUDY DESIGN, SIZE, DURATION

We applied single-cell RNA sequencing (scRNA-seq) to capture the transcriptomes of human in vivo oocytes (IVO) (n = 10) from 7 donors and rIVM oocytes (n = 10) from 10 donors. The effects of maternal age and ovarian responses on rIVM oocyte transcriptomes were also studied. In parallel, we studied the effect of gallic acid on the maturation rate of mouse oocytes cultured in IVM medium with (n = 84) and without (n = 85) gallic acid.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human oocytes were collected from donors aged 28-41 years with a body mass index of <30. RNA extraction, cDNA generation, library construction and sequencing were performed in one preparation. scRNA-seq data were then processed and analysed. Selected genes in the rIVM versus IVO comparison were validated by quantitative real-time PCR. For the gallic acid study, we collected immature oocytes from 5-month-old mice and studied the effect of 10-μM gallic acid on their maturation rate.

MAIN RESULTS AND THE ROLE OF CHANCE

The transcriptome profiles of rIVM/IVO oocytes showed distinctive differences. A total of 1559 differentially expressed genes (DEGs, genes with at least 2-fold change and adjusted P < 0.05) were found to be enriched in metabolic processes, biosynthesis and oxidative phosphorylation. Among these DEGs, we identified a repression of WNT/β-catenin signalling in rIVM when compared with IVO oocytes. We found that oestradiol levels exhibited a significant age-independent correlation with the IVO mature oocyte ratio (MII ratio) for each donor. rIVM oocytes from women with a high MII ratio were found to have over-represented cellular processes such as anti-apoptosis. To further identify targets that contribute to the poor clinical outcomes of rIVM, we compared oocytes collected from young donors with a high MII ratio with oocytes from donors of advanced maternal age and lower MII ratio, and revealed that CREB1 is an important regulator. Thus, our study identified that GATA-1/CREB1/WNT signalling was repressed in both rIVM oocytes versus IVO oocytes and in rIVM oocytes of lower versus higher quality. Consequently we investigated gallic acid, as a potential antioxidant substrate in human rIVM medium, and found that it increased the mouse oocyte maturation rate by 31.1%.

LARGE SCALE DATA

Raw data from this study can be accessed through GSE158539.

LIMITATIONS, REASONS FOR CAUTION

In the rIVM oocytes of the high- and low-quality comparison, the number of samples was limited after data filtering with stringent selection criteria. For the oocyte stage identification, we were unable to predict the presence of oocyte spindle, so polar body extrusion was the only indicator.

WIDER IMPLICATIONS OF THE FINDINGS

This study showed that GATA-1/CREB1/WNT signalling was repressed in rIVM oocytes compared with IVO oocytes and was further downregulated in low-quality rIVM oocytes, providing us the foundation of subsequent follow-up research on human oocytes and raising safety concerns about the clinical use of rescued oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Collaborative Research Fund, Research Grants Council, C4054-16G, and Research Committee Funding (Research Sustainability of Major RGC Funding Schemes), The Chinese University of Hong Kong. The authors have no conflicts of interest to declare.

Lung but not brain cancer cell malignancy inhibited by commonly used anesthetic propofol during surgery: Implication of reducing cancer recurrence risk

Introduction

Intravenous anesthesia with propofol was reported to improve cancer surgical outcomes when compared with inhalational anesthesia. However, the underlying molecular mechanisms largely remain unknown.

Objectives

The anti-tumor effects of propofol and the possible underlying mechanism including altered metabolic and signaling pathways were studied in the current study.

Methods

The cell viability, proliferation, migration, and invasion of cancer cells were analyzed with CCK-8, Ki-67 staining, wound healing, and Transwell assay, respectively. The protein changes were analyzed with Western blot and immunofluorescent staining. The metabolomics alteration was studied with 1H-NMR spectroscopy. The gene expression regulations were analyzed with PCR gene array and qRT-PCR experiments.

Results

In this study, we found that propofol reduced cell viability and inhibited cell proliferation, migration and invasion of lung cancer cells, but not neuroglioma cells. In lung cancer cells, propofol downregulated glucose transporter 1 (GLUT1), mitochondrial pyruvate carrier 1 (MPC1), p-Akt, p-Erk1/2, and hypoxia- inducible factor 1 alpha (HIF-1 α ) expressions and upregulated pigment epithelium-derived factor (PEDF) expression. Propofol increased intracellular glutamate and glycine but decreased acetate and formate whilst increased glucose, lactate, glutamine, succinate, pyruvate, arginine, valine, isoleucine, and leucine and glycerol, and decreased acetate, ethanol, isopropanol in the culture media of lung cancer cells. Furthermore, VEGFA, CTBP1, CST7, CTSK, CXCL12, and CXCR4 gene expressions were downregulated, while NR4A3, RB1, NME1, MTSS1, NME4, SYK, APC, and FAT1 were upregulated following the propofol treatment. Consistent with the phenotypical changes, these molecular and metabolic changes were not found in the neuroglioma cells.

Conclusion

Our findings indicated anti-tumor effects of propofol on the lung cancer but not brain cancer, through the regulation of tumor metastasis-related genes, multi-cellular signaling and cellular metabolism.

The Adenosine A2A Receptor Activation in Nucleus Accumbens Suppress Cue-Induced Reinstatement of Propofol Self-administration in Rats

Propofol has shown strong addictive properties in rats and humans. Adenosine A2A receptors (A2AR) in the nucleus accumbens (NAc) modulate dopamine signal and addictive behaviors such as cocaine- and amphetamine-induced self-administration. However, whether A2AR can modulate propofol addiction remains unknown. AAV-shA2AR was intra-NAc injected 3 weeks before the propofol self-administration training to test the impacts of NAc A2AR on establishing the self-administration model with fixed ratio 1 (FR1) schedule. Thereafter, the rats were withdrawal from propofol for 14 days and tested cue-induced reinstatement of propofol seeking behavior on day 15. The propofol withdrawal rats received one of the doses of CGS21680 (A2AR agonist, 2.5-10.0 ng/site), MSX-3 (A2AR antagonist, 5.0-20.0 μg/site) or eticlopride (D2 receptor (D2R) antagonist, 0.75-3.0 μg/site) or vehicle via intra-NAc injection before relapse behavior test. The numbers of active and inactive nose-poke response were recorded. Focal knockdown A2AR by shA2AR did not affect the acquisition of propofol self-administration behavior, but enhance cue-induced reinstatement of propofol self-administration compared with the AAV-shCTRLgroup. Pharmacological activation of the A2AR by CGS21680 (≥ 5.0 ng/site) attenuated cue-induced reinstatement of propofol self-administration behavior. Similarly, pharmacological blockade of D2R by eticlopride (0.75-3.0 μg/site) attenuated propofol seeking behavior. These effects were reversed by the administration of MSX-3 (5.0-20.0 μg/site). The A2AR- and D2R-mediated effects on propofol relapse were not confounded by the learning process, and motor activity as the sucrose self-administration and locomotor activity were not affected by all the treatments. This study provides genetic and pharmacological evidence that NAc A2AR activation suppresses cue-induced propofol relapse in rats, possibly by interacting with D2R.

Short-term perfluorooctane sulfonate exposure impairs Leydig cell regeneration in the adult rat testis via targeting hedgehog signaling

Perfluorooctane sulfonate is related to male reproductive dysfunction in rats and humans. However, the underlying mechanism remains unknown. Here, we reported the effects of short-term exposure to perfluorooctane sulfonate on the regeneration of Leydig cells in vivo and investigated possible mechanisms in vitro. After adult male Sprague-Dawley rats were gavaged perfluorooctane sulfonate (0, 5 or 10 mg/kg/day) for 7 days and then injected intraperitoneally ethane dimethane sulfonate next day to eliminate Leydig cells, the Leydig cell regeneration process was monitored. Perfluorooctane sulfonate significantly lowered serum testosterone levels, reduced the number of regenerated Leydig cells, down-regulated the expression of Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, and Dhh) and their proteins at doses of 5 and 10 mg/kg 35 and 56 days after ethane dimethane sulfonate. Using a 3D seminiferous tubule culture system to study the development of stem Leydig cells, we found that perfluorooctane sulfonate inhibited stem Leydig cell proliferation and differentiation and hedgehog signaling pathway. In conclusion, a short-term exposure to perfluorooctane sulfonate can inhibit the development of stem Leydig cells into the Leydig cell lineage via direct suppression of hedgehog signaling pathway and indirect inhibition of desert hedgehog section by Sertoli cells.

Phthalate inhibits Leydig cell differentiation and promotes adipocyte differentiation

Studies have shown that phthalates are capable of affecting the development and functions of male reproductive system. The effect of phthalates on Leydig cell functions is well documented. However, little is known about their potential effects on the functions of stem Leydig cells (SLC). In the present study, we have examined the effects of mono-(2-ethylhexyl) phthalate (MEHP) on SLC functions in vitro by culturing seminiferous tubules and isolated SLCs. The results indicate that MEHP can significantly inhibit the proliferation and differentiation of SLCs in both the organ and cell culture systems. Interestingly, the minimal effective concentration that is able to affect SLC function was lower in the tubule culture system (1 μM) than in the isolated cells (10 μM), suggesting a possible involvement of the niche cells. Also, MEHP appeared to affect both the efficiency of SLCs to form Leydig cells and a selected group of Leydig cell-specific genes, including Lhcgr, Scarb1, Hsd3b1, Cyp17a1, Star, Srd5a1, Akr1c14, Insl3, Hao2 and Pah. Since SLCs are multipotent, we also tested the effect of MEHP on the differentiation of SLCs to adipocytes. Though MEHP by itself can not specify SLCs into adipocyte lineage, it indeed significantly increased the adipogenic activity of SLCs if used with an adipocyte inducing medium by up-regulation of multiple adipogenic-related genes, including Pparg and Cebpa. Overall, the results indicate that MEHP inhibits SLCs differentiating into Leydig lineage while stimulates the differentiating potential of SLCs to adipocytes.

A biochemical comparison of the lung, colonic, brain, renal, and ovarian cancer cell lines using 1H-NMR spectroscopy

Cancer cell lines are often used for cancer research. However, continuous genetic instability-induced heterogeneity of cell lines can hinder the reproducibility of cancer research. Molecular profiling approaches including transcriptomics, chromatin modification profiling, and proteomics are used to evaluate the phenotypic characteristics of cell lines. However, these do not reflect the metabolic function at the molecular level. Metabolic phenotyping is a powerful tool to profile the biochemical composition of cell lines. In the present study, 1H-NMR spectroscopy-based metabolic phenotyping was used to detect metabolic differences among five cancer cell lines, namely, lung (A549), colonic (Caco2), brain (H4), renal (RCC), and ovarian (SKOV3) cancer cells. The concentrations of choline, creatine, lactate, alanine, fumarate and succinate varied remarkably among different cell types. The significantly higher intracellular concentrations of glutathione, myo-inositol, and phosphocholine were found in the SKOV3 cell line relative to other cell lines. The concentration of glutamate was higher in both SKOV3 and RCC cells compared with other cell lines. For cell culture media analysis, isopropanol was found to be the highest in RCC media, followed by A549 and SKOV3 media, while acetone was the highest in A549, followed by RCC and SKOV3. These results demonstrated that 1H-NMR-based metabolic phenotyping approach allows us to characterize specific metabolic signatures of cancer cell lines and provides phenotypical information of cellular metabolism.

Modified paediatric preoperative risk prediction score to predict postoperative ICU admission in children: a retrospective cohort study

OBJECTIVE

To integrate intrinsic surgical risk into the paediatric preoperative risk prediction score (PRPS) model to construct a more comprehensive risk scoring system (modified PRPS) and improve the prediction accuracy of postoperative intensive care unit (ICU) admission in paediatric patients.

DESIGN

This was a retrospective study conducted between 1 January and 30 December 2016. Data on age, American Society of Anaesthesiology physical status (ASA-PS), oxygen saturation, prematurity, non-fasted status, severity of surgery and immediate transfer to the ICU after surgery were collected. The modified PRPS was developed by logistic regression in the derivation cohort; it was tested and compared with the paediatric PRPS and ASA-PS by the Hosmer-Lemeshow test, the receiver operating characteristic (ROC) curve and Kappa analysis in the validation cohort.

SETTING

Hospital-based study in China.

PARTICIPANTS

Paediatric patients (≤14 years) who underwent surgery under general anaesthesia were included, and those who needed reoperation due to surgical complications or stayed in the ICU preoperatively were excluded.

MAIN OUTCOME MEASURE

ICU admission rate, defined as any patients' direct disposition from the operating room to the ICU immediately after the surgery.

RESULTS

A total of 9261 paediatric patients were included in this study, with 418 patients admitted to the ICU. In the validation cohort, the modified PRPS model fit the test data well (deciles of risk goodness-of-fit χ²=6.84, p=0.077). The area under the ROC curve of the modified PRPS, paediatric PRPS and ASA-PS were 0.963, 0.941 and 0.870, respectively (p<0.05), and the Kappa values were 0.620, 0.286 and 0.267. Analyses in the cohort indicated that the modified PRPS was superior to the paediatric PRPS and ASA-PS.

CONCLUSIONS

The modified PRPS integrating intrinsic surgical risk shows better prediction accuracy than the previous PRPS.

Paraquat exposure delays late-stage Leydig cell differentiation in rats during puberty

Paraquat is a fast and non-selective herbicide that is widely used in crop cultivation and conservation tillage systems. Animal experiments have shown that paraquat decreases sperm quality and testicular organ coefficient, but its effects on the development of Leydig cells remain unclear. The objective of the current study was to investigate the effects of paraquat exposure on the Leydig cell development in rats during puberty. Twenty-eight male 35-day-old Sprague-Dawley rats were divided into 4 groups: 0, 0.5, 2.0, and 8 mg kg^-1 d^-1 paraquat. Paraquat was gavaged for 10 d. Adult Leydig cells were isolated and treated with paraquat for 24 h. Paraquat in vivo significantly decreased body and testis weights at 8 mg kg^-1 and lowered serum testosterone levels at 2 and 8 mg kg^-1 without affecting the levels of serum luteinizing hormone and follicle-stimulating hormone. Paraquat did not alter Leydig cell number and PCNA labeling index. Real-time PCR showed that paraquat down-regulated the expression of Lhcgr, Scarb1, Cyp11a1, Cyp17a1, and Hsd17b3 genes and their proteins at 2 or 8 mg kg^-1, while it up-regulated the expression of Srd5a1 at 8 mg kg^-1. Paraquat increased ROS and decreased testosterone production by Leydig cells at 1 and 10 μM after in vitro 24-h exposure. Vitamin E (40 μg/ml) reversed paraquat-induced ROS and suppression of testosterone synthesis in vitro. In conclusion, paraquat directly delays Leydig cell differentiation to block testosterone synthesis via down-regulating the expression of critical testosterone synthesis-related genes and up-regulating the expression of testosterone metabolic enzyme (Srd5a1) gene and possibly via increasing ROS production.

The association of the optimal bolus of dexmedetomidine with its favourable haemodynamic outcomes in adult surgical patients under general anaesthesia

AIMS

Dexmedetomidine is highly specific α2-adrenoceptor agonist. A single bolus of dexmedetomidine can achieve clinical therapeutic effect. Therefore, it is essential to know the safety margin between the clinical effectiveness dosages of dexmedetomidine and its side effect.

METHODS

A total of 42 patients who underwent elective thyroidectomy were enrolled in this study. Dexmedetomidine was given as a single bolus injection 30 min towards the end of surgery. The up-and-down sequential schedule was used in this study. The starting dose of dexmedetomidine was set at 0.1 μg/kg in the first patient and the next patient would then receive a dose of dexmedetomidine decremented by 0.05 μg/kg if the prior patient's baseline heart rate (HR) had a decrease of ≥20% and/or mean arterial blood pressure (MAP) increase or decrease of ≥20%, otherwise, the following patient would receive an incremental 0.05 μg/kg dose of dexmedetomidine. The analytic techniques of linear, linear-logarithmic, exponential regressions and centred isotonic regression were used to determine the ED50 of dexmedetomidine and the residual standard errors were calculated for the comparison of goodness of fit among the different models.

RESULTS

The median (interquartile range [range]) lowest HR was 57 beats/min (53-63.3[46-76]) with an average HR decrease of 8.0 beats/min (5-13 [4 to 23]). The median (interquartile range [range]) highest MAP was 98 mmHg (91.8-105 [83-126]) with a MAP increase of 10.0 mmHg (6.8-18.0 [2-24]). The ED50 (95% confidence interval) from 4 different statistical approaches (linear, linear-logarithmic, exponential regressions and centred isotonic regression) were 0.262 μg/kg (0.243, 0.306), 0.252 μg/kg (0.238, 0.307), 0.283 μg/kg (0.238, 0.307), and 0.278 μg/kg, respectively. Among the 4 models, the exponential regression had the least residual standard error (0.03618).

CONCLUSION

The ED50 derived from 4 statistical models for an intravenous bolus of dexmedetomidine without significant haemodynamic effects was distributed in a narrow range of 0.252-0.283 μg/kg, and the exponential regression was the model to best match the study data.

Paraquat exposure delays stem/progenitor Leydig cell regeneration in the adult rat testis

Paraquat, a widely used nonselective herbicide, is a serious hazard to human health. However, the effects of paraquat on the male reproductive system remain unclear. In this study, adult male Sprague Dawley rats were intraperitoneally injected ethane dimethane sulfonate (EDS, 75 mg/kg) to initiate a regeneration of Leydig cells. EDS-treated rats were orally exposed to paraquat (0.5, 2, 8 mg/kg/day) from post-EDS day 17 to day 28 and effects of paraquat on Leydig and Sertoli cell functions on post-EDS day 35 and day 56 were investigated. Paraquat significantly decreased serum testosterone levels at 2 and 8 mg/kg. Paraquat lowered Leydig cell Hsd17b3, Srd5a1, and Hsd11b1 mRNA levels but increased Hsd3b1 on post-EDS day 35. Paraquat lowered Cyp11a1, Cyp17a1, and Hsd11b1 but increased Srd5a1 on post-EDS day 56. However, paraquat did not alter Leydig cell number and PCNA labeling index. Epididymal staining showed that few sperms were observed in paraquat-treated rats. Primary culture of adult Leydig cells showed that paraquat diminished testosterone output and induced reactive oxygen species generation at 1 and 10 μM and apoptosis rate at 10 μM. In conclusion, a short-term exposure to paraquat delays Leydig cell regeneration from stem/progenitor Leydig cells, causing low production of testosterone and an arrest of spermatogenesis.

Flurbiprofen Inhibits Androgen Productions in Rat Immature Leydig Cells

Flurbiprofen is one of the nonsteroidal anti-inflammatory drugs. Whether flurbiprofen affects androgen biosynthesis in Leydig cells is still unknown. Immature Leydig cells (ILCs) isolated from 35-day-old male Sprague-Dawley rats were cultured with 0-100 μM flurbiprofen for 24 h and medium androgen levels and Leydig cell mRNA levels were measured. Immature Leydig cells were also incubated with 100 μM flurbiprofen for 3 h in combination with luteinizing hormone (LH), 8bromo-cAMP, 22R-OH-cholesterol, pregnenolone, progesterone, androstenedione, testosterone, and dihydrotestosterone, respectively, and medium androgen levels were measured. The ROS generation and apoptosis rate were also investigated. The direct effects of flurbiprofen on androgen biosynthetic and metabolizing enzyme activities were measured. Flurbiprofen significantly inhibited basal, LH, and 8bromo-cAMP stimulated androgen production at 10 and 100 μM. Further study demonstrated that flurbiprofen competitively inhibited rat and human testis 3β-hydroxysteroid dehydrogenase (HSD3B) activity with the half maximal inhibitory concentration (IC₅₀) values of 0.95 μM for rat enzyme and 6.31 μM for human enzyme. In addition, flurbiprofen down-regulated the expression of Srd5a1 and Akr1c14 at 1, 10, and 100 μM. Flurbiprofen also down-regulated Lhcgr expression at 100 μM. Flurbiprofen at 10 and 100 μM increased ROS production and apoptosis rate of rat Leydig cells. In conclusion, flurbiprofen directly inhibits HSD3B activity and the expression levels of Srd5a1 and Akr1c14 in rat Leydig cells, thus leading to the reduction of androgen secretion.

Regulation of BTB dynamics in spermatogenesis - insights from the adjudin toxicant model

During spermatogenesis, cell organelles and germ cells, most notably haploid spermatids, are transported across the seminiferous epithelium so that fully developed spermatids line-up at the edge of the tubule lumen to undergo spermiation at stage VIII of the cycle. Studies have suggested that the microtubule (MT)-based cytoskeleton is necessary to support these cellular events. However, the regulatory molecule(s) and underlying mechanism(s) remain poorly understood. Herein, we sought to better understand this event by using an adjudin-based animal model. Adult rats were treated with adjudin at low-dose (10 mg/kg b.w.) which by itself had no notable effects on spermatogenesis. Rats were also treated with low-dose adjudin combined with overexpression of two endogenously produced blood-testis barrier (BTB) modifiers, namely rpS6 [ribosomal protein S6, the downstream signaling protein of mammalian target of rapamycin complex 1 (mTORC1)] and F5-peptide (a biological active peptide released from laminin-γ3 chain at the Sertoli-spermatid interface) versus the two BTB modifiers alone. Overexpression of these two BTB modifiers in the testis was shown to enhance delivery of adjudin to the testis, effectively inducing disruptive changes in MT cytoskeletons, causing truncation of MT conferred tracks that led to their collapse across the epithelium. The net result was massive germ cell exfoliation in the tubules, disrupting germ cell transport and cell adhesion across the seminiferous epithelium that led to aspermatogenesis. These changes were the result of disruptive spatial expression of several MT-based regulatory proteins. In summary, MT cytoskeleton supported by the network of MT regulatory proteins is crucial to maintain spermatogenesis.

Characterization and differentiation of CD51+ Stem Leydig cells in adult mouse testes

It was reported previously that adult mouse stem Leydig cells (SLCs) express CD51 (integrin α-chain V). However, it is still unclear whether all CD51⁺ cells are SLCs. In the present study, we found that CD51⁺ cells can be classified into two sub-groups, a weakly-staining group (CD51⁺) and a strongly-staining group (CD51⁺⁺). The CD51⁺ cells expressed common SLC marker genes, including Nestin, Pdgfra and Coup-tf2, while CD51⁺⁺ cells did not express these genes. Instead, they expressed macrophage markers, such as F4/80, Cd115 and Tnfa. When these cells were induced to differentiate in vitro, the CD51⁺ cells, but not CD51⁺⁺ cells, formed Leydig cells. Overall, our results showed that although SLCs expressed CD51, not all CD51-expressing cells are SLCs. The cells that expressed high levels of CD51 are actually macrophages.

F5-Peptide and mTORC1/rpS6 Effectively Enhance BTB Transport Function in the Testis-Lesson From the Adjudin Model

During spermatogenesis, the blood-testis barrier (BTB) undergoes cyclic remodeling that is crucial to support the transport of preleptotene spermatocytes across the immunological barrier at stage VIII to IX of the epithelial cycle. Studies have shown that this timely remodeling of the BTB is supported by several endogenously produced barrier modifiers across the seminiferous epithelium, which include the F5-peptide and the ribosomal protein S6 [rpS6; a downstream signaling molecule of the mammalian target of rapamycin complex 1 (mTORC1)] signaling protein. Herein, F5-peptide and a quadruple phosphomimetic (and constitutively active) mutant of rpS6 [i.e., phosphorylated (p-)rpS6-MT] that are capable of inducing reversible immunological barrier remodeling, by making the barrier "leaky" transiently, were used for their overexpression in the testis to induce BTB opening. We sought to examine whether this facilitated the crossing of the nonhormonal male contraceptive adjudin at the BTB when administered by oral gavage, thereby effectively improving its BTB transport to induce germ cell adhesion and aspermatogenesis. Indeed, it was shown that combined overexpression of F5-peptide and p-rpS6-MT and a low dose of adjudin, which by itself had no noticeable effects on spermatogenesis, was capable of perturbing the organization of actin- and microtubule (MT)-based cytoskeletons through changes in the spatial expression of actin- and MT-binding/regulatory proteins to the corresponding cytoskeleton. These findings thus illustrate the possibility of delivering drugs to any target organ behind a blood-tissue barrier by modifying the tight junction permeability barrier using endogenously produced barrier modifiers based on findings from this adjudin animal model.

Propofol Inhibits Androgen Production in Rat Immature Leydig Cells

Background: Propofol is a widely used anesthetic. Whether propofol inhibits androgen production by rat Leydig cells and the underlying mechanism remains unclear. The objective of the current study was to examine the effects of propofol exposure to rat primary immature Leydig cells and to define propofol-induced inhibition of steroidogenic enzymes in both rat and human testes in vitro.

Methods: Immature Leydig cells were purified from 35-day-old male Sprague–Dawley rats and were exposed to propofol for 3 h. The androgen production by Leydig cells under basal, luteinizing hormone, 8bromo-cAMP, and steroid-substrate stimulated conditions and gene expression of Leydig cells after exposure to propofol were measured. Immature Leydig cells were treated with propofol for 3 h and switched to propofol-free medium for additional 3 and 9 h to test whether propofol-induced inhibition is reversible. ³H-Steroids were used to evaluate the direct action of propofol on cytochrome P450 cholesterol side chain cleavage (CYP11A1), 3β-hydroxysteroid dehydrogenase (HSD3B), cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17A1), and 17β-hydroxysteroid dehydrogenase 3 (HSD17B3) activities in rat and human testes in vitro.

Results: Propofol significantly lowered luteinizing hormone and 8bromo-cAMP stimulated androgen production by Leydig cells after 3-h exposure. Further investigation showed that propofol down-regulated the expression of Cyp11a1 and Cyp17a1 and their proteins at 5 and 50 µM, although it up-regulated Lhcgr expression at 50 µM. Propofol significantly suppressed phosphorylation of ERK1/2 and induced ROS production in immature Leydig cells at 5 and 50 µM. Propofol significantly induced apoptosis of immature Leydig cells at 50 µM. Propofol specifically inhibited rat and human testis HSD3B activities in vitro. The half maximal inhibitory concentrations of propofol for rat and human HSD3B enzymes were 1.011 ± 0.065 and 3.498 ± 0.067 µM, respectively. The mode of action of propofol of inhibiting HSD3B was competitive when pregnenolone was added. At 50 µM, propofol did not directly inhibit rat and human testis CYP11A1, CYP17A1, and HSD17B3 activities in vitro.

Conclusion: Propofol inhibits androgen production via both directly inhibiting HSD3B activity and down-regulating Cyp11a1 and Cyp17a1 expression in Leydig cells. Suppression of steroidogenic enzymes is presumably associated with the lower production of androgen by Leydig cells after propofol treatment. However, propofol-induced inhibition on androgen production is reversible.

mTORC1/rpS6 and spermatogenic function in the testis-insights from the adjudin model

mTORC1/rpS6 signaling complex promoted Sertoli blood-testis barrier (BTB) remodeling by perturbing Sertoli cell-cell adhesion site known as the basal ectoplasmic specialization (ES). mTORC1/rpS6 complex also promoted disruption of spermatid adhesion at the Sertoli-spermatid interface called the apical ES. Herein, we performed analyses using the adjudin (a non-hormonal male contraceptive drug under development) model, wherein adjudin was known to perturb apical and basal ES function when used at high dose. Through direct administration of adjudin to the testis, adjudin at doses that failed to perturb BTB integrity per se, overexpression of an rpS6 phosphomimetic (i.e., constitutively active) mutant (i.e., p-rpS6-MT) that modified BTB function considerably potentiated adjudin efficacy. This led to disorderly spatial expression of proteins necessary to maintain the proper cytoskeletal organization of F-actin and microtubules (MTs) across the seminiferous epithelium, leading to germ cell exfoliation and aspermatogenesis. These findings yielded important insights regarding the role of mTORC1/rpS6 signaling complex in regulating BTB homeostasis.

Diethylstilbestrol inhibits human and rat 11β-hydroxysteroid dehydrogenase 2

Glucocorticoid hormone might cause intrauterine growth restriction. The glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase 2 (HSD11B2) in the placenta eliminates excess levels of glucocorticoids during pregnancy. The aim of the current study was to define the effects of diethylstilbestrol (DES) on HSD11B2 activity in the mammalian placentas and identify its mode of action. Rat and human placental microsomal HSD11B2 were incubated with different concentrations of DES, and IC50 values were determined. The mode of action was analyzed by incubation of DES together with substrates, glucocorticoid and NAD+. DES suppressed rat and human HSD11B2 with IC50 values of 5.33 and 12.62 μM, respectively. DES was a competitive inhibitor of rat and human HSD11B2 when steroid substrates were added, while it was an uncompetitive inhibitor when cofactor NAD+ was exposed. Oral administration of DES (0.5 mg/kg) to the rat delayed the cortisol metabolism in adult female Sprague-Dawley rats, as indicated by the increases in cortisol's elimination half-life, maximum concentration and area under the curve. In conclusion, DES is a potent HSD11B2 inhibitor, possibly contributing to the intrauterine growth restriction.

mTORC1/rpS6 signaling complex modifies BTB transport function: an in vivo study using the adjudin model

Studies have shown that the mTORC1/rpS6 signaling cascade regulates Sertoli cell blood-testis barrier (BTB) dynamics. For instance, specific inhibition of mTORC1 by treating Sertoli cells with rapamycin promotes the Sertoli cell barrier, making it "tighter." However, activation of mTORC1 by overexpressing a full-length rpS6 cDNA clone (i.e., rpS6-WT, wild type) in Sertoli cells promotes BTB remodeling, making the barrier "leaky." Also, there is an increase in rpS6 and p-rpS6 (phosphorylated and activated rpS6) expression at the BTB in testes at stages VIII-IX of the epithelial cycle, and it coincides with BTB remodeling to support the transport of preleptotene spermatocytes across the barrier, illustrating that rpS6 is a BTB-modifying signaling protein. Herein, we used a constitutively active, quadruple phosphomimetic mutant of rpS6, namely p-rpS6-MT of p-rpS6-S235E/S236E/S240E/S244E, wherein Ser (S) was converted to Glu (E) at amino acid residues 235, 236, 240, and 244 from the NH2 terminus by site-directed mutagenesis, for its overexpression in rat testes in vivo using the Polyplus in vivo jet-PEI transfection reagent with high transfection efficiency. Overexpression of this p-rpS6-MT was capable of inducing BTB remodeling, making the barrier "leaky." This thus promoted the entry of the nonhormonal male contraceptive adjudin into the adluminal compartment in the seminiferous epithelium to induce germ cell exfoliation. Combined overexpression of p-rpS6-MT with a male contraceptive (e.g., adjudin) potentiated the drug bioavailability by modifying the BTB. This approach thus lowers intrinsic drug toxicity due to a reduced drug dose, further characterizing the biology of BTB transport function.

Fibroblast growth factor homologous factor 1 stimulates Leydig cell regeneration from stem cells in male rats

Fibroblast growth factor homologous factor 1 (FHF1) is an intracellular protein that does not bind to cell surface fibroblast growth factor receptor. Here, we report that FHF1 is abundantly present in Leydig cells with up‐regulation during its development. Adult male Sprague Dawley rats were intraperitoneally injected with 75 mg/kg ethane dimethane sulphonate (EDS) to ablate Leydig cells to initiate their regeneration. Then, rats daily received intratesticular injection of FHF1 (0, 10 and 100 ng/testis) from post‐EDS day 14 for 14 days. FHF1 increased serum testosterone levels without affecting the levels of luteinizing hormone and follicle‐stimulating hormone. FHF1 increased the cell number staining with HSD11B1, a biomarker for Leydig cells at the advanced stage, without affecting the cell number staining with CYP11A1, a biomarker for all Leydig cells. FHF1 did not affect PCNA‐labelling index in Leydig cells. FHF1 increased Leydig cell mRNA (Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Insl3, Nr5a1 and Hsd11b1) and their protein levels in vivo. FHF1 increased preadipocyte biomarker Dlk1 mRNA level and decreased fully differentiated adipocyte biomarker (Fabp4 and Lpl) mRNA and their protein levels. In conclusion, FHF1 promotes Leydig cell regeneration from stem cells while inhibiting the differentiation of preadipocyte/stem cells into adipocytes in EDS‐treated testis.

CAMSAP2 Is a Microtubule Minus-End Targeting Protein That Regulates BTB Dynamics Through Cytoskeletal Organization

During spermatogenesis, microtubule (MT) cytoskeleton in Sertoli cells confers blood-testis barrier (BTB) function, but the regulators and mechanisms that modulate MT dynamics remain unexplored. In this study, we examined the role of calmodulin-regulated spectrin-associated protein (CAMSAP)2 (a member of the CAMSAP/Patronin protein family), and a minus-end targeting protein (-TIP) that binds to the minus-end (i.e., slow-growing end) of polarized MTs involved in determining MT length, in Sertoli cell function. CAMSAP2 was found to localize at discrete sites across the Sertoli cell cytosol, different from end-binding protein 1 (a microtubule plus-end tracking protein that binds to the plus-end of MTs), and colocalized with MTs. CAMSAP2 displayed a stage-specific expression pattern, appearing as tracklike structures across the seminiferous epithelium in adult rat testes that lay perpendicular to the basement membrane. CAMSAP2 knockdown by RNA interference was found to promote Sertoli cell tight junction (TJ) barrier function, illustrating its role in inducing TJ remodeling under physiological conditions. To further examine the regulatory role of CAMSAP2 in BTB dynamics, we used a perfluorooctanesulfonate (PFOS)-induced Sertoli cell injury model for investigations. CAMSAP2 knockdown blocked PFOS-induced Sertoli cell injury by promoting proper distribution of BTB-associated proteins at the cell-cell interface. This effect was mediated by the ability of CAMSAP2 knockdown to block PFOS-induced disruptive organization of MTs, but also F-actin, across cell cytosol through changes in cellular distribution/localization of MT- and actin-regulatory proteins. In summary, CAMSAP2 is a regulator of MT and actin dynamics in Sertoli cells to support BTB dynamics and spermatogenesis.

Current Status and Challenges of NRF2 as a Potential Therapeutic Target for Diabetic Cardiomyopathy

Diabetic cardiomyopathy is one of the main causes of heart failure and death in patients with diabetes mellitus. Reactive oxygen species produced excessively in diabetes mellitus cause necrosis, apoptosis, ferroptosis, inflammation, and fibrosis of the myocardium as well as impair the cardiac structure and function. It is increasingly clear that oxidative stress is a principal cause of diabetic cardiomyopathy. The transcription factor nuclear factor-erythroid 2 p45-related factor 2 (NRF2) activates the transcription of more than 200 genes in the human genome. Most of the proteins translated from these genes possess anti-oxidant, anti-inflammatory, anti-apoptotic, anti-ferroptotic, and anti-fibrotic actions. There is a growing body of evidence indicating that NRF2 and its target genes are crucial in preventing high glucose-induced oxidative damage in diabetic cardiomyopathy. Recently, many natural and synthetic activators of NRF2 are shown to possess promising therapeutic effects on diabetic cardiomyopathy in animal models of diabetic cardiomyopathy. Targeting NRF2 signaling by pharmacological entities is a potential approach to ameliorating diabetic cardiomyopathy. However, the persistent high expression of NRF2 in cancer tissues also protects the growth of cancer cells. This "dark side" of NRF2 increases the challenges of using NRF2 activators to treat diabetic cardiomyopathy. In addition, some NRF2 activators were found to have off-target effects. In this review, we summarize the current status and challenges of NRF2 as a potential therapeutic target for diabetic cardiomyopathy.

In utero exposure to bisphenol A disrupts fetal testis development in rats

Bisphenol A (BPA) is widely used in consumer products and is a potential endocrine disruptor linked with abnormal development of male reproductive tract. However, its action and its effects on the pathways in the development of male gonad are still unclear. Here we report that effects of BPA exposure during gestation on male gonad development. Sprague-Dawley rats were gavaged daily with BPA (0, 4, 40, and 400 mg/kg body weight) from gestational day 12 to day 21. BPA dose-dependently decreased serum testosterone levels (0.45 ± 0.08 ng/ml and 0.32 ± 0.08 ng/ml for 40 and 400 mg/kg BPA, respectively) versus the control level (1.11 ± 0.22 ng/ml, Mean ± SE). BPA lowered Leydig cell Insl3 and Hsd17b3 mRNA and their protein levels at doses of 40 and 400 mg/kg. BPA also lowered Leydig cell (Lhcgr, Cyp11a1, and Cyp17a1) and Sertoli cell (Amh) mRNA and their protein levels at 400 mg/kg. BPA decreased fetal Leydig cell number via inhibiting their proliferation, but it did not affect fetal Sertoli cell number. In conclusion, the current study shows that in utero exposure to BPA inhibits fetal Leydig and Sertoli cell differentiation, possibly disrupting the development of male reproductive tract.

Effects of spermatogenic cycle on Stem Leydig cell proliferation and differentiation

We reported previously that stem Leydig cells (SLC) on the surfaces of rat testicular seminiferous tubules are able to differentiate into Leydig cells. The proliferation and differentiation of SLCs seem likely to be regulated by niche cells, including nearby germ and Sertoli cells. Due to the cyclical nature of spermatogenesis, we hypothesized that the changes in the germ cell composition of the seminiferous tubules as spermatogenesis proceeds may affect tubule-associated SLC functions. To test this hypothesis, we compared the ability of SLCs associated with tubules at different stages of the cycle to differentiate into Leydig cells in vitro. SLCs associated with stages IX-XI were more active in proliferation and differentiation than SLCs associated with stages VII-VIII. However, when the SLCs were isolated from each of the two groups of tubules and cultured in vitro, no differences were seen in their ability to proliferate or differentiate. These results suggested that the stage-dependent local factors, not the SLCs themselves, explain the stage-dependent differences in SLC function. TGFB, produced in stage-specific fashion by Sertoli cells, is among the factors shown in previous studies to affect SLC function in vitro. When TGFB inhibitors were included in the cultures of stages IX-XI and VII-VIII tubules, stage-dependent differences in SLC development were reduced, suggesting that TGFB may be among the paracrine factors involved in the stage-dependent differences in SLC function. Taken together, the findings suggest that there is dynamic interaction between SLCs and germ/Sertoli cells within the seminiferous tubules that may affect SLC proliferation and differentiation.

In utero Exposure to Atrazine Disrupts Rat Fetal Testis Development

Atrazine (ATR) is a commonly used agricultural herbicide and a potential endocrine disruptor that may cause testicular dysgenesis. The objective of the present study was to investigate the effects of atrazine on fetal testis development after in utero exposure. Female Sprague-Dawley rats were gavaged daily with vehicle (corn oil, control) or atrazine (25, 50, and 100 mg/kg body weight/day) from gestational day 12 to 21. Atrazine dose-dependently decreased serum testosterone levels of male pups, with a significant difference from the control recorded at a dose of 100 mg/kg. In addition, atrazine significantly increased fetal Leydig cell aggregation at a dose of 100 mg/kg. Atrazine increased fetal Leydig cell number but not Sertoli cell number. However, atrazine down-regulated Scarb1 and Cyp17a1 in the fetal Leydig cell per se and Hsd17b3 and Dhh in the Sertoli cell per se. These results demonstrated that in utero exposure to atrazine disrupted rat fetal testis development.

In utero exposure to triphenyltin disrupts rat fetal testis development

Triphenyltin is an organotin that is widely used as an anti-fouling agent and may have endocrine-disrupting effects. The objective of the current study was to investigate effects of triphenyltin on the development of rat fetal testis. Female pregnant Sprague Dawley dams were gavaged daily with triphenyltin (0, 0.5, 1, and 2 mg/kg body weight/day) from gestational day 12 to day 21. Triphenyltin dose-dependently decreased serum testosterone levels (0.971 ± 0.072 and 0.972 ± 0.231 ng/ml at 1 and 2 mg/kg, respectively) from control level (2.099 ± 0.351 ng/ml). Triphenyltin at 1 and 2 mg/kg doses also induced fetal Leydig cell aggregation, decreased fetal Leydig cell size and cytoplasmic size. Triphenyltin decreased the expression levels of Lhcgr, Scarb1, Star, Cyp11a1, Cyp17a1, Insl3, Fshr, Pdgfa, and Sox9 by 0.5 mg/kg dose and above. However, triphenyltin did not affect Leydig and Sertoli cell numbers. In conclusion, the current study indicated that in utero exposure of triphenyltin disrupted fetal Leydig and Sertoli cell development.

Lambda-cyhalothrin delays pubertal Leydig cell development in rats

Lambda-cyhalothrin (LCT) is a widely used broad-spectrum pyrethroid insecticide and is expected to cause deleterious effects on the male reproductive system. However, the effects of LCT on Leydig cell development during puberty are unclear. The current study addressed these effects. Twenty-eight-day-old male Sprague Dawley rats orally received LCT (0, 0.25, 0.5 or 1 mg/kg body weight/day) for 30 days. The levels of serum testosterone, luteinizing hormone, and follicle-stimulating hormone, Leydig cell number, and its specific gene and protein expression were determined. LCT exposure lowered serum testosterone levels at doses of 0.5 and 1 mg/kg and luteinizing hormone levels at a dose of 1 mg/kg, but increased follicle-stimulating hormone levels at doses of 0.5 and 1 mg/kg. LCT lowered Star and Hsd3b1 mRNA or their protein levels at a dose of 1 mg/kg. Immature Leydig cells were purified from pubertal rats and treated with different concentrations of LCT for 24 h and medium androgen levels, Leydig cell mRNA and protein levels, the mitochondrial membrane potential (△Ψm), and the apoptotic rate of immature Leydig cells were investigated. LCT inhibited androgen production at 5 μM and downregulated Scarb1 at 0.05 μM, Hsd3b1 and Hsd11b1 at 0.5 μM, and Cyp11a1 at 5 μM. LCT also decreased △Ψm at 0.5 and 50 μM. In conclusion, LCT can influence the function of Leydig cells.

Dopamine D1 Receptor Within Basolateral Amygdala Is Involved in Propofol Relapse Behavior Induced by Cues

Propofol has been proven to be potentially abused by humans and laboratory animals; however, studies that have examined propofol relapse behavior are limited, and its underlying mechanism remains unclear. In this study, we examined whether basolateral amygdala-specific or systematic administration of the dopamine receptor antagonist alters cue-induced propofol-seeking behaviors in a rat model. Male Sprague-Dawley rats first received 14 days of propofol self-administration training, where active nose poke resulted in the delivery of propofol infusion paired with a tone and light cues. After 1-30 days of forced abstinence, the cue-induced propofol-seeking behaviors were tested in the operant chamber. We demonstrated, for the first time, after a few days of withdrawal from intravenous bolus administration of propofol, propofol-related cues could induce robust reinstatement of drug-seeking behavior. Systematic administration of dopamine D₁ receptor antagonist (SCH-23390) or dopamine D₂ receptor antagonist (spiperone) inhibited propofol relapse behavior induced by drug-related cues. Furthermore, we show that microinfusion of SCH-23390 into basolateral amygdala dose-dependently attenuated cue-induced propofol drug-seeking behavior, whereas infusion of spiperone had no effect on the propofol relapse behavior. Our results reveal the involvement of dopamine receptors within the basolateral amygdala in the cue-induced propofol relapse behavior in rats.

In utero exposure to hexavalent chromium disrupts rat fetal testis development

Hexavalent chromium (Cr⁶⁺) acts as an endocrine disruptor. Herein, we investigated effects of Cr⁶⁺ on the development of rat fetal Leydig and Sertoli cells, which support differentiation of the male reproductive tract in late gestation. Female pregnant Sprague Dawley rats were gavaged with potassium dichromate (0, 3, 6, and 12 mg/kg) from gestational days (GD) 12 to GD 21. Leydig and Sertoli cell function was evaluated by investigating serum testosterone levels, cell number and distribution, and the expression levels of Leydig and Sertoli cell genes and proteins. Cr⁶⁺ increased serum testosterone level at dose of 3 mg/kg (1.170 ± 0.121 ng/ml vs. 0.720 ± 0.082 ng/ml in the control), while lowered it at dose of 12 mg/kg (0.400 ± 0.098 ng/ml). In addition, it showed that Cr⁶⁺ dose-dependently reduced Leydig cell size and cytoplasmic size and decreased the percentage of medium fetal Leydig cell cluster at dose of 12 mg/kg. Further study demonstrated that the expression of Leydig cell (Lhcgr, Scarb1, and Hsd3b1) and Sertoli cell (Fshr, Pdgfa, and Lif) genes in the testis was upregulated at dose of 3 mg/kg while the expression of Lhcgr, Hsd17b3 and Igf1 was downregulated by Cr⁶⁺ at dose of 12 mg/kg. In conclusion, Cr⁶⁺ had biphasic effects on fetal Leydig cell development with low dose to stimulate testosterone production and high dose to inhibit it, possibly via biphasically regulating growth factor gene expression in fetal Sertoli cells.

Interleukin 6 inhibits the differentiation of rat stem Leydig cells

Inflammation causes male hypogonadism. Several inflammatory cytokines, including interleukin 6 (IL-6), are released into the blood and may suppress Leydig cell development. The objective of the present study was to investigate whether IL-6 affected the proliferation and differentiation of rat stem Leydig cells. Leydig cell-depleted rat testis (in vivo) and seminiferous tubules (in vitro) with ethane dimethane sulfonate (EDS) were used to explore the effects of IL-6 on stem Leydig cell development. Intratesticular injection of IL-6 (10 and 100 ng/testis) from post-EDS day 14 to 28 blocked the regeneration of Leydig cells, as shown by the lower serum testosterone levels (21.6% of the control at 100 ng/testis dose), the down-regulated Leydig cell gene (Lhcgr, Star, Cyp11a1, Cyp17a1, and Hsd17b3) expressions, and the reduced Leydig cell number. Stem Leydig cells on the surface of the seminiferous tubules were induced to enter the Leydig cell lineage in vitro in the medium containing luteinizing hormone and lithium. IL-6 (1, 10, and 100 ng/ml) concentration-dependently decreased testosterone production and Lhcgr, Cyp11a1, Cyp17a1, Hsd17b3 and Insl3 mRNA levels. The IL-6 mediated effects were antagonized by Janus kinase 1 (JAK) inhibitor (filgotinib) and Signal Transducers and Activators of Transcription 3 (STAT3) inhibitor (S3I-201), indicating that a JAK-STAT3 signaling pathway is involved. In conclusion, our results demonstrated that IL-6 was an inhibitory factor of stem Leydig cell development.

Enhancement of Adiponectin Ameliorates Nonalcoholic Fatty Liver Disease via Inhibition of FoxO1 in Type I Diabetic Rats

Nonalcoholic fatty liver disease (NAFLD) is a common liver disease which has been previously shown to be associated with type 2 diabetes mellitus (T2DM). Recent research has indicated that type 1 diabetes mellitus (T1DM) is also involved in the development of nonalcoholic fatty liver disease, whereas the underlying mechanisms are largely unknown. Forkhead box O1 (FoxO1) and adiponectin (APN) have been proposed to play an important role in the processes in NAFLD in T1DM. We herein investigated the effects of FoxO1 and APN on the development of NAFLD and the underlying mechanism in streptozotocin-induced T1DM. Serum liver enzymes AST, ALT, and triglyceride (TG) were determined by commercially available kits. Blood glucose levels were measured by the OneTouch Ultra glucose meter. Relevant protein expression was tested by Western blot analysis. Results showed that serum AST, ALT, and TG were all significantly increased in T1DM rats, which was ameliorated by application of APN or selective inhibition of FoxO1 with AS1842856. Moreover, APN and AS1842856 both decreased the expression of liver nuclear FoxO1 which was significantly increased in diabetic rats. However, the inhibition of FoxO1 did not alter the expression of APN and its receptors. We also found that Akt1 expression was significantly declined in diabetic rat which was restored by APN and moderately and significantly increased by FoxO1 inhibition. It is concluded that APN ameliorates NAFLD via inhibition of FoxO1 through Akt1/FoxO1 signaling pathway.

VEGF mitigates histone-induced pyroptosis in the remote liver injury associated with renal allograft ischemia-reperfusion injury in rats

Clinical evidence has indicated a possible link between renal injury and remote liver injury. We investigated whether extracellular histone mediates remote hepatic damage after renal graft ischemia-reperfusion injury, while vascular endothelial growth factor (VEGF) is protective against remote hepatic injury. In vitro, hepatocyte HepG2 cultures were treated with histone. In vivo, the Brown-Norway renal graft was stored in 4°C preservation solution for 24 hours and then transplanted into a Lewis rat recipient; blood samples and livers from recipients were harvested 24 hours after surgery. Prolonged cold ischemia in renal grafts enhanced liver injury 24 hours after engraftment. Caspase-1, ASC, NLRP3, and AIM2 expressions in hepatocyte, CD68⁺ -infiltrating macrophages, tissue, and serum interleukin-1β and -18 were greatly elevated, indicating that pyroptosis occurred in the liver and resulted in acute liver functional impairment. Blocking the caspase-1 pathway decreased the number of necrotic hepatocytes. VEGF treatment suppressed the hepatocyte pyroptosis and liver function was partially restored. Our data suggested that renal allograft ischemia-reperfusion injury is likely associated with acute liver damage due to hepatocyte pyroptosis induced by histone and such injury may be protected by VEGF administration. VEGF, therefore, may serve as a new strategy against other remote organ injuries related to renal transplantation.

Ziram Delays Pubertal Development of Rat Leydig Cells

Ziram [zinc, bis (dimethyldithiocarbamate)] is an agricultural dithiocarbamate fungicide. By virtual screening, we have identified that ziram is a potential endocrine disruptor. To investigate its effects on pubertal development of Leydig cells, 35-day-old male Sprague Dawley rats orally received ziram (2 or 4 mg/kg/d) for 4 weeks and immature Leydig cells isolated from 35-day-old rat testes were treated with ziram (0.5-50 μM in vitro). Serum hormones, Leydig cell number and specific gene or protein expression levels after in vivo treatment were determined and medium androgen levels were measured as well as apoptosis of Leydig cells after in vitro treatment were determined. In vivo exposure to ziram lowered testosterone and follicle-stimulating hormone levels, and reduced Leydig cell number, and downregulated Leydig cell specific gene or protein expression levels. Ziram exposure in vitro inhibited androgen production and steroidogenic enzyme activities in Leydig cells by downregulating expression levels of P450 cholesterol side cleavage enzyme (Cyp11a1), 3β-hydroxysteroid dehydrogenase 1 (Hsd3b1), 17α-hydroxylase/17,20-lyase (Cyp17a1), and 17β-hydroxysteroid dehydrogenase 3 (Hsd17b3) via downregulating the steroidogenic factor 1 (Nr5a1) at a concentration as low as 5 μM. In conclusion, ziram exposure disrupts Leydig cell development during puberty possibly via downregulating Nr5a1.

Mechanistic Insights into PFOS-Mediated Sertoli Cell Injury

Studies have proven that per- and polyfluoroalkyl substances are harmful to humans, most notably perfluorooctanesulfonate (PFOS). PFOS induces rapid disorganization of actin- and microtubule (MT)-based cytoskeletons in primary cultures of rodent and human Sertoli cells, perturbing Sertoli cell gap junction communication, thereby prohibiting Sertoli cells from maintaining cellular homeostasis in the seminiferous epithelium to support spermatogenesis. PFOS perturbs several signaling proteins/pathways, such as FAK and mTORC1/rpS6/Akt1/2. The use of either an activator of Akt1/2 or overexpression of a phosphomimetic (and constitutively active) mutant of FAK or connexin 43 has demonstrated that such treatment blocks PFOS-induced Sertoli cell injury by preventing actin- and MT-based cytoskeletal disorganization. These findings thus illustrate an approach to manage PFOS-induced reproductive dysfunction.

Regulation of spermatid polarity by the actin- and microtubule (MT)-based cytoskeletons

It is conceivable that spermatid apico-basal polarity and spermatid planar cell polarity (PCP) are utmost important to support spermatogenesis. The orderly arrangement of developing germ cells in particular spermatids during spermiogenesis are essential to obtain structural and nutrient supports from the fixed number of Sertoli cells across the limited space of seminiferous epithelium in the tubules following Sertoli cell differentiation by ∼17 day postpartum (dpp) in rodents and ∼12 years of age at puberty in humans. Yet few studies are found in the literature to investigate the role of these proteins to support spermatogenesis. Herein, we briefly summarize recent findings in the field, in particular emerging evidence that supports the concept that apico-basal polarity and PCP are conferred by the corresponding polarity proteins through their effects on the actin- and microtubule (MT)-based cytoskeletons. While much research is needed to bridge our gaps of understanding cell polarity, cytoskeletal function, and signaling proteins, a critical evaluation of some latest findings as summarized herein provides some important and also thought-provoking concepts to design better functional experiments to address this important, yet largely expored, research topic.

Gestational exposure to ziram disrupts rat fetal Leydig cell development

Ziram is an endocrine disruptor and may cause birth abnormality of the male reproductive system. However, the effects of ziram on fetal Leydig cell (FLC) development are still unknown. The objective of the present study was to determine the endocrine-disrupting effect of ziram on rat FLC development after gestational exposure. Pregnant Sprague Dawley dams were randomly divided into 5 groups and were gavaged with 0 (corn oil, the control), 1, 2, 4, or 8 mg/kg ziram from gestational day 12 (GD12) to GD21. FLC development was evaluated by measuring serum testosterone, FLC number and distribution, and the expression levels of Leydig and Sertoli cell genes. Ziram significantly increased serum testosterone level at 1 mg/kg (1.350 ± 0.099 ng/ml vs. 0.989 ± 0.106 ng/ml in the control), while it remarkably lowered it at 8 mg/kg (0.598 ± 0.086 ng/ml). Quantitative immunohistochemical staining showed that ziram increased FLC number via stimulating cell proliferation at 1 mg/kg and lowered it via inhibiting its proliferation at 8 mg/kg without affecting Sertoli cell number. Further study demonstrated that the expression of Nr5a1, Lhcgr, Scarb1, Star, Cyp11a1, and Cyp17a1 genes and proteins in the testis was upregulated at 1 mg/kg and the expression of Leydig (Nr5a1, Lhcgr, Scarb1, Star, Cyp11a1, Cyp17a1, and Insl3) and Sertoli cell (Fshr, Hsd17b3, Dhh, Amh, and Sox9) genes and proteins was downregulated by ziram at 8 mg/kg. In conclusion, ziram had biphasic effects on FLC development with low dose to increase FLC number and function and high dose to decrease them.

Diverged Effects of Piperine on Testicular Development: Stimulating Leydig Cell Development but Inhibiting Spermatogenesis in Rats

Background: Piperine is the primary pungent alkaloid isolated from the fruit of black peppercorns. Piperine is used frequently in dietary supplements and traditional medicines. The objective of the present study was to investigate the effects of piperine on the testis development in the pubertal rat.

Methods: Piperine (0 or 5 or 10 mg/kg) was gavaged to 35-day-old male Sprague-Dawley rats for 30 days. Serum levels of testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured. The development of adult Leydig cell population was also analyzed 65 days postpartum. For in vitro studies, immature Leydig cells were isolated from 35-day-old male rats and treated with 50 μM piperine in the presence of different steroidogenic stimulators/substrates for 24 h.

Results: Thirty-day treatment of rats with piperine significantly increased serum T levels without affecting LH concentrations. However, piperine treatment reduced serum FSH levels. Consistent with increase in serum T, piperine increased Leydig cell number, cell size, and multiple steroidogenic pathway proteins, including steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase 1, 17α-hydroxylase/20-lyase, and steroidogenic factor 1 expression levels. Piperine significantly increased the ratio of phospho-AKT1 (pAKT1)/AKT1, phosphos-AKT2 (pAKT2)/AKT2, and phospho-ERK1/2 (pERK1/2)/ERK1/2 in the testis. Interestingly, piperine inhibited spermatogenesis. Piperine in vitro also increased androgen production and stimulated cholesterol side-chain cleavage enzyme and 17α-hydroxylase/20-lyase activities in immature Leydig cells.

Conclusion: Piperine stimulates pubertal Leydig cell development by increasing Leydig cell number and promoting its maturation while it inhibits spermatogenesis in the rat. ERK1/2 and AKT pathways may involve in the piperine-mediated stimulation of Leydig cell development.

Actin nucleator Spire 1 is a regulator of ectoplasmic specialization in the testis

Germ cell differentiation during the epithelial cycle of spermatogenesis is accompanied by extensive remodeling at the Sertoli cell-cell and Sertoli cell-spermatid interface to accommodate the transport of preleptotene spermatocytes and developing spermatids across the blood-testis barrier (BTB) and the adluminal compartment of the seminiferous epithelium, respectively. The unique cell junction in the testis is the actin-rich ectoplasmic specialization (ES) designated basal ES at the Sertoli cell-cell interface, and the apical ES at the Sertoli-spermatid interface. Since ES dynamics (i.e., disassembly, reassembly and stabilization) are supported by actin microfilaments, which rapidly converts between their bundled and unbundled/branched configuration to confer plasticity to the ES, it is logical to speculate that actin nucleation proteins play a crucial role to ES dynamics. Herein, we reported findings that Spire 1, an actin nucleator known to polymerize actins into long stretches of linear microfilaments in cells, is an important regulator of ES dynamics. Its knockdown by RNAi in Sertoli cells cultured in vitro was found to impede the Sertoli cell tight junction (TJ)-permeability barrier through changes in the organization of F-actin across Sertoli cell cytosol. Unexpectedly, Spire 1 knockdown also perturbed microtubule (MT) organization in Sertoli cells cultured in vitro. Biochemical studies using cultured Sertoli cells and specific F-actin vs. MT polymerization assays supported the notion that a transient loss of Spire 1 by RNAi disrupted Sertoli cell actin and MT polymerization and bundling activities. These findings in vitro were reproduced in studies in vivo by RNAi using Spire 1-specific siRNA duplexes to transfect testes with Polyplus in vivo-jetPEI as a transfection medium with high transfection efficiency. Spire 1 knockdown in the testis led to gross disruption of F-actin and MT organization across the seminiferous epithelium, thereby impeding the transport of spermatids and phagosomes across the epithelium and perturbing spermatogenesis. In summary, Spire 1 is an ES regulator to support germ cell development during spermatogenesis.