TRPC6 Knockout Alleviates Renal Fibrosis through PI3K/AKT/GSK3B Pathway.

OBJECTIVE: Renal fibrosis is the ultimate pathway of various forms of acute and chronic kidney damage. Notably, the knockout of transient receptor potential channel 6 (TRPC6) has shown promise in alleviating renal fibrosis. However, the regulatory impact of TRPC6 on renal fibrosis remains unclear. METHODS: In vivo, TRPC6 knockout (TRPC6-/-) mice and age-matched 129 SvEv (WT) mice underwent unilateral renal ischemia-reperfusion (uIR) injury surgery on the left renal pedicle or sham operation. Kidneys and serum were collected on days 7, 14, 21, and 28 after euthanasia. In vitro, primary tubular epithelial cells (PTECs) were isolated from TRPC6-/- and WT mice, followed by treatment with transforming growth factor ß1 (TGFß1) for 72 h. The anti-fibrotic effect of TRPC6-/- and the underlying mechanisms were assessed through hematoxylin-eosin staining, Masson staining, immunostaining, qRT-PCR, and Western blotting. RESULTS: Increased TRPC6 expression was observed in uIR mice and PTECs treated with TGFß1. TRPC6-/- alleviated renal fibrosis by reducing the expression of fibrotic markers (Col-1, α-SMA, and vimentin), as well as decreasing the apoptosis and inflammation of PTECs during fibrotic progression both in vivo and in vitro. Additionally, we found that the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3 beta (GSK3ß) signaling pathway, a pivotal player in renal fibrosis, was down-regulated following TRPC6 deletion. CONCLUSION: These results suggest that the ablation of TRPC6 may mitigate renal fibrosis by inhibiting the apoptosis and inflammation of PTECs through down-regulation of the PI3K/AKT/GSK3ß pathway. Targeting TRPC6 could be a novel therapeutic strategy for preventing chronic kidney disease.

Plasma-Activated Solutions Mitigates DSS-Induced Colitis via Restoring Redox Homeostasis and Reversing Microbiota Dysbiosis.

Ulcerative colitis is a chronic disease that increases the risk of developing colorectal cancer. Conventional medications are limited by drug delivery and a weak capacity to modulate the inflammatory microenvironment. Further, gut microbiota dysbiosis caused by mucosal damage and dysregulated redox homeostasis leads to frequent recurrence. Therefore, promoting mucosal healing and restoring redox homeostasis is considered the initial step in treating ulcerative colitis. Plasma-activated solutions (PAS) are liquids rich in various reactive nitrogen species (RNS) and reactive oxygen species (ROS) and are used to treat multiple diseases. However, its effect on ulcerative colitis remains to be examined. Therefore, using a DSS-induced mice colitis model, it is found that PAS has the potential to treat colitis and prevent its recurrence by promoting intestinal mucosal repair, reducing inflammation, improving redox homeostasis, and reversing gut microbiota dysbiosis. Further, an equipment is designed for preparing PAS without using nitrogen; however, after treatment with the Nitro-free PAS, the therapeutic effect of PAS is significantly weakened or even lost, indicating that RNS may be the main mediator by which PAS exerts its therapeutic effects. Overall, this study demonstrates the treatment of ulcerative colitis as a novel application of PAS.

Inhibition of STIM1 alleviates high glucose-induced proliferation and fibrosis by inducing autophagy in mesangial cells.

Diabetic nephropathy (DN) is a renal microvascular complication caused by diabetes mellitus. One of the most typical characteristics of DN is glomerular mesangial cells (GMCs) proliferation. Stromal interaction molecule 1 (STIM1), a Ca2+ channel, is involved in many diseases. In this study, we investigated the role of STIM1 in the proliferation and fibrosis in high glucose (HG)-induced HBZY-1 cells. We found that the expression of STIM1 was increased in renal tissues of diabetic rat and HBZY-1 cells stimulated by HG. Downregulation of STIM1-mediated SOCE suppressed hyperglycemic cell proliferation and fibrosis by activating autophagy. In addition, the inhibitory effect of downregulating STIM1 on cells was blocked by autophagy inhibitor Bafilomycin A1 (BafA1). Moreover, this experiment also showed that STIM1 regulated autophagy, cell proliferation and fibrosis via PI3K/AKT/mTOR signal pathway. These results clarify the role of STIM1 in HBZY-1 cells and its mechanism, and provide a new target for the treatment of DN.

Trends in using of antihypertensive medication among US CKD adults, NHANES 2001-2018.

Objective: Blood pressure (BP) control rates among adult patients taking antihypertensive medications in the United States have not improved over the last decade. Many CKD adults require more than one class of antihypertensive agent to reach the BP target recommended by the guidelines. However, no study has quantified the proportion of adult CKD patients taking antihypertensive medication who are on monotherapy or combination therapy. Methods: National Health and Nutrition Examination Survey data during 2001-2018 was used, including adults with CKD taking antihypertensive medication (age ≥ 20 years, n = 4,453). BP control rates were investigated under the BP targets recommended by the 2021 KDIGO, the 2012 KDIGO, and the 2017 ACC/AHA guidelines. Results: The percentages of uncontrolled BP among US adults with CKD taking antihypertensive medication were 81.4% in 2001-2006 and 78.2% in 2013-2018. The proportion of monotherapy of antihypertensive regimen were 38.6, 33.3, and 34.6% from 2001 to 2006, 2007-2012, and 2013-2018, with no obvious difference. Similarly, there was no significant change in percentages of dual-therapy, triple-therapy, and quadruple-therapy. Although proportion of CKD adults not treated with ACEi/ARB decreased from 43.5% in 2001-2006 to 32.7% in 2013-2018, treatment of ACEi/ARB among patients with ACR > 300 mg/g had no significant change. Conclusion: The BP control rates among US adult CKD patients taking antihypertensive medications have not improved from 2001 to 2018. Mono-therapy accounted for about one third of adult CKD patients taking antihypertensive medication and not changed. Increasing antihypertensive medication combination therapy may help improve BP control in CKD adults in the United States.

Neonatal exposure to low-dose X-ray causes behavioral defects and abnormal hippocampal development in mice.

Development of the hippocampus is critical for its normal maturation. However, there is no systematic study on the effects of low-dose (≤2 Gy) neonatal X-ray exposure on different cells at different developmental stages of the mouse hippocampus. The present study demonstrated that irradiation with 2 Gy at postnatal day (PD) 3 in mice induced anxiety and impairment of spatial learning and memory in adult mice. Neuroinflammatory cells were observed in the dentate gyrus (DG) and CA3 areas of the hippocampus at PD3 + 1. X-ray irradiation impaired neuronal complexity and neurogenesis. However, the number of astrocytes and microglia in the hippocampus was increased the first day after irradiation, and then decreased 21 days later. The protein expression levels of NF-κB, C/EBP homologous protein (CHOP), and γH2 A histone family member X (γH2 AX) increased from 7 to 21 days after irradiation, or till 90 days after irradiation for IL-1ß, whereas those of hippocampal sirtuin1 (SIRT1) decreased after 21 days of irradiation at PD3. These results suggest that neonatal X-ray irradiation-induced neuroinflammation impaired neuroplasticity and neurogenesis in the hippocampus, leading to the anxiety and spatial memory disorder during adulthood. The mechanisms involved in the induction of developmental neurotoxicity following low-dose irradiation may involve the inflammation-mediated signaling pathway IL-1ß/ SIRT1/CHOP.

Investigation of a novel ring-cusp magnetically confined plasma bridge neutralizer.

The plasma bridge neutralizer (PBN) based on a tungsten filament is a promising technique of a thermionic DC electron source where a hot filament is immersed in an inert gas flow and electrons are "bridged" from a small orifice to the ion beam. PBNs have been widely used in space propulsion and industrial applications due to their relatively simple structure and low power consumption. However, they have well-known disadvantages, namely, low emission current density and short lifetime. In this article, we propose a novel ring-cusp magnetically confined PBN (RCM-PBN) to address these issues. In the RCM-PBN, electrons are confined by a ring-cusp magnetic field, which improves the ionization efficiency and reduces the discharge chamber wall losses. Electrical insulation of the orifice plate from the chamber wall prevents a large number of electrons from being collected by the orifice plate, which greatly improves the extracted electron current. The effects of different operating parameters on the extracted electron current were studied through experiments. It was found that the increase in the extracted electron current with the extraction voltage was related to the anode spot formation. Analysis of the gas utilization factor and electron extraction cost shows that the optimal operating condition was obtained at an argon mass flow rate of 1.2 SCCM and a heater power of 45 W. At its optimum, a stable electron current of 1.1 A was extracted from the RCM-PBN with a gas utilization factor of 12.8 and an electron extraction cost of 143 W/A.

The Role of TRPC6 in Renal Ischemia/Reperfusion and Cellular Hypoxia/Reoxygenation Injuries.

Renal ischemia/reperfusion (I/R), a major cause of acute kidney injury (AKI), is a serious clinical event in patients during post-renal transplantation. I/R is associated with renal dysfunction and tubular apoptosis, and calcium (Ca2+) overload has been reported to be a crucial factor on tubular apoptosis in I/R injury (IRI). The canonical transient receptor potential channel 6 (TRPC6), a type of non-selective Ca2+ channel, is involved in many renal diseases. Our earlier study identified that TRPC6-mediated Ca2+ influx plays a novel role in suppressing cytoprotective autophagy triggered by oxidative stress in primary tubular epithelial cells (TECs). This study explored the potential beneficial impact of TRPC6 knockout (TRPC6-/-) and the relevant cellular mechanisms against I/R-induced AKI in mice. Measuring changes of renal function, apoptotic index, and autophagy in mouse kidneys that suffered 24 h reperfusion after 40 min ischemia and working in vitro with TECs that suffered 24 h reoxygenation after 24 h hypoxia, we found that 1) IRI tissues had increased TRPC6 expression and TRPC6 knockout significantly ameliorated renal damage induced by IRI; 2) TRPC6 knockout enhanced the level of autophagy and alleviated the depolarization of mitochondrial membrane potential (ψm, MMP) and apoptotic changes upon IRI; and 3) IRI tissues had increased p-AKT and p-ERK1/2 expressions, while TRPC6 knockout could markedly reduce the phosphorylation of AKT and ERK1/2. These discoveries suggest that, by reducing Ca2+ overload, the underlying protective mechanism of TRPC6-/- may be involved in down-regulation of PI3K/AKT and ERK signaling, which is likely to provide a new avenue for future AKI therapies.

Intense boundary emission destroys normal radio-frequency plasma sheath.

The plasma sheath is the non-neutral space charge region that isolates bulk plasma from a boundary. Radio-frequency (RF) sheaths are formed when applying RF voltage to electrodes. Generally, applied bias is mainly consumed by a RF sheath, which shields an external field. Here we report evidence that an intense boundary emission destroys a normal RF sheath and establishes a type of RF plasma where external bias is consumed by bulk plasma instead of a sheath. Ions are naturally confined while plasma electrons are unobstructed, generating a strong RF current in the entire plasma, combined with a unique particle and energy balance. The proposed model offers the possibility for ion erosion mitigation of a plasma-facing component. It also inspires techniques for reaction rate control in plasma processing and wave mode conversion.

Transient Receptor Potential Channel 6 Knockout Ameliorates Kidney Fibrosis by Inhibition of Epithelial-Mesenchymal Transition.

Kidney fibrosis is generally confirmed to have a significant role in chronic kidney disease, resulting in end-stage kidney failure. Epithelial-mesenchymal transition (EMT) is an important molecular mechanism contributing to fibrosis. Tubular epithelial cells (TEC), the major component of kidney parenchyma, are vulnerable to different types of injuries and are a significant source of myofibroblast by EMT. Furthermore, TRPC6 knockout plays an anti-fibrotic role in ameliorating kidney damage. However, the relationship between TRPC6 and EMT is unknown. In this study, TRPC6-/- and wild-type (WT) mice were subjected to a unilateral ureteric obstruction (UUO) operation. Primary TEC were treated with TGF-ß1. Western blot and immunofluorescence data showed that fibrotic injuries alleviated with the inhibition of EMT in TRPC6-/- mice compared to WT mice. The activation of AKT-mTOR and ERK1/2 pathways was down-regulated in the TRPC6-/- mice, while the loss of Na+/K+-ATPase and APQ1 was partially recovered. We conclude that TRPC6 knockout may ameliorate kidney fibrosis by inhibition of EMT through down-regulating the AKT-mTOR and ERK1/2 pathways. This could contribute to the development of effective therapeutic strategies on chronic kidney diseases.

Compound C Protects Against Cisplatin-Induced Nephrotoxicity Through Pleiotropic Effects.

AICAR (Acadesine/AICA riboside) as an activator of AMPK, can protect renal tubular cells from cisplatin induced apoptosis. But in our experiment, the dorsomorphin (compound C, an inhibitor of AMPK) also significantly reduced cisplatin induced renal tubular cells apoptosis. Accordingly, we tested whether compound C can protect cisplatin-induced nephrotoxicity and the specific mechanism. Here, we treated Boston University mouse proximal tubular cells (BUMPT-306) with cisplatin and/or different dosages of AICAR (Acadesine/AICA riboside) or compound C to confirm the effect of AICAR and compound C in vitro. The AMPK-siRNA treated cells to evaluate whether the protective effect of compound C was through inhibiting AMPK. Male C57BL/6 mice were used to verify the effect of compound C in vivo. Both compound C and AICAR can reduce renal tubular cells apoptosis in dose-dependent manners, and compound C decreased serum creatinine and renal tubular injury induced by cisplatin. Mechanistically, compound C inhibited P53, CHOP and p-IREα during cisplatin treatment. Our results demonstrated that compound C inhibited AMPK, but the renal protective effects of compound C were not through AMPK. Instead, compound C protected cisplatin nephrotoxicity by inhibiting P53 and endoplasmic reticulum (ER) stress. Therefore, compound C may protect against cisplatin-induced nephrotoxicity through pleiotropic effects.

Prenatal nicotine exposure induces depression­like behavior in adolescent female rats via modulating neurosteroid in the hippocampus.

Prenatal nicotine exposure (PNE) is closely related to depression in offspring. However, the underlying mechanism is still unclear. We hypothesized that neurosteroid in the hippocampus may mediate PNE­induced depression­like behaviors. Nicotine was subcutaneously administered (1.0 mg/kg) to pregnant rats twice daily from gestational day (GD) 9 to 20. In adolescent offspring, PNE significantly increased immobility time and decreased the sucrose preference in female rats. The numbers of hippocampal neurons declined in the CA3 and DG regions. Steroidogenic acute regulatory protein (StAR) expression was suppressed in female rats. In fetal offspring, the neuronal numbers of CA3 regions in PNE female fetal hippocampal were significantly decreased, accompanied by the enhanced content of corticosterone and StAR expression. These data indicated that PNE induced depression­like behavior in adolescent female rats via the regulation of neurosteroid levels in the hippocampus.

Epigenetic modulation during hippocampal development.

The hippocampus is located in the limbic system and is vital in learning ability, memory formation and emotion regulation, and is associated with depression, epilepsy and mental retardation in an abnormal developmental situation. Several factors have been found to modulate the development of the hippocampus, and epigenetic modification have a crucial effect in this progress. The present review summarizes the epigenetic modifications, including DNA methylation, histone acetylation, and non-coding RNAs, regulating all stages of hippocampal development, focusing on the growth of Ammons horn and the dentate gyrus in humans and rodents. These modifications may significantly affect hippocampal development and health in addition to cognitive processes.

Loss of thin spines and small synapses contributes to defective hippocampal function in aged mice.

Aging is a normal physiological process associated with impairments in cognitive function, including learning and memory. Here, the underlying synaptic mechanisms by which aging leads to the decline of spatial learning and memory function were investigated in 25-month-old aged mice versus 2-month-old young mice. Deficits of spatial learning and memory, as well as selective loss of thin spines, but not mushroom-type spines on apical dendrites of CA1 pyramidal cells were found in aged mice. Specifically, loss of thin spines in aged mice with memory deficits was primarily found on dendritic segments located in the Schaffer pathway, and the density of thin spines significantly correlated with spatial memory performance. The loss of thin spines was evidenced by a decrease in small synapses that express diminutive amounts of postsynaptic density protein-95 and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR1. Furthermore, mushroom-type spines and GluR1-expressed large synapses were not affected in aged mice with impaired memory. Taken together, these data suggest that the selective loss of those highly plastic thin spines with sparse postsynaptic density protein-95 and GluR1 receptors may significantly contribute to cognitive deficits in aged individuals.

Development and analysis of a novel printed circuit board electrostatic comb system for micro-newton thrust stand calibration.

An electrostatic calibration technique is highly flexible in producing a wide range of force and it is widely applied for nano-newton to micro-newton thrust stand calibration. This paper proposes a novel method for electrostatic comb implementation and related experiments have been carried out. Based on the printed circuit board and commercial fins, the comb can be realized flexibly with the output force conveniently extended. The force generated by this kind of comb is theoretically analyzed. Different from the traditional comb structure, the conductive area of the comb fixed plate is minimized to improve the force consistency over engagement. The influence of fin length, fin number, applied voltage, and engagement on the output force has been studied experimentally. The final comb system is capable of producing steady force in the range 13-5040 µN with the relative error within 5%. With a high voltage pulse generator, this system could produce calibration impulse bit in the range 1-1000 µN s for which the lowest level can be far more extended to the nanonewton range with a shorter pulse width, a lower voltage, and a reduced number of fins. Moreover, the calibrator has a rather flat force-engagement characteristic when the engagement is in the range of 6 mm-16 mm, while the variation of electrostatic force is within 5%. This calibrator has a wide output range and great consistency, and it is beneficial for the thrust stand calibration.

Running-induced memory enhancement correlates with the preservation of thin spines in the hippocampal area CA1 of old C57BL/6 mice.

The effects of prolonged physical training on memory performance and underlying synaptic mechanisms were investigated in old C57BL/6 mice. Training via voluntary running wheels was initiated at 16 months of age and continued for 5 months (1 hour per day and 5 days per week), followed by learning and memory test and spine/synapse analysis. Trained old mice were compared with their age-matched sedentary controls and aged adult controls. This training improved hippocampal-dependent spatial learning and memory function in old mice, and enhanced cognition was accompanied by increased density of spines on CA1 pyramidal cells in the hippocampus. Particularly, the training selectively affected thin spines that carry small synapses in the stratum radiatum, the target area of CA3 Schaffer pathway. Furthermore, increased density of thin spines positively correlates with improved memory performance. Finally, the training prevented age-related loss of postsynaptic density protein-95 in the Schaffer pathway. These data suggest that the preservation of thin spines carrying small synapses in specific hippocampal region contributes critically to running-related improvement of learning and memory function.

Involvement of Bim in Photofrin-mediated photodynamically induced apoptosis.

BACKGROUND/AIMS: Photodynamic therapy (PDT) is a promising noninvasive technique, which has been successfully applied to the treatment of human cancers. Studies have shown that the Bcl-2 family proteins play important roles in PDT-induced apoptosis. However, whether Bcl-2-interacting mediator of cell death (Bim) is involved in photodynamic treatment remains unknown. In this study, we attempt to determine the effect of Bim on Photofrin photodynamic treatment (PPT)-induced apoptosis in human lung adenocarcinoma ASTC-a-1 cells. METHODS: The translocation of Bim/Bax of the cells were monitored by laser confocal scanning microscope. The levels of Bim protein and activated caspase-3 in cells were detected by western blot assay. Caspase-3 activities were measured by Caspase-3 Fluorogenic Substrate (Ac-DEVD-AFC) analysis. The induction of apoptosis was detected by Hoechst 33258 and PI staining as well as flow cytometry analysis. The effect of Bim on PPT-induced apoptosis was determined by RNAi. RESULTS: BimL translocated to mitochondria in response to PPT, similar to the downstream pro-apoptotic protein Bax activation. PPT increased the level of Bim and activated caspase-3 in cells and that knockdown of Bim by RNAi significantly protected against caspase-3 activity. PPT-induced apoptosis were suppressed in cells transfected with shRNA-Bim. CONCLUSION: We demonstrated the involvement of Bim in PPT-induced apoptosis in human ASTC-a-1 lung adenocarcinoma cells and suggested that enhancing Bim activity might be a potential strategy for treating human cancers.