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The hyporheic zone (HZ) is a saturated sediment layer connecting groundwater (GW) and surface water (SW) along a riverbed and river channel. The HZ plays an important role in connecting SW and GW in a river ecosystem, thereby helping maintain the ecological health of rivers. Studies on the HZ have therefore increased in many disciplines. This study used the VFLUX 2 software to assess vertical fluid flux in the HZ, in which the Hatch, Kerry, McCallum, and Luce models were applied and compared. The simulations were calibrated against data measured by the US Geological Survey at a water diversion channel within the Walker River Basin in Nevada. Using COMSOL Multiphysics, we developed a two-dimensional coupled numerical model of the saturated seepage and temperature fields, calibrated against measured temperature data. We also determined the vertical seepage velocity and compared the simulations with those of the analytical models in VFLUX 2. The results showed that the temperature field distribution of the HZ is obviously nonuniform in space. With a deeper monitoring point, the thermal response of each temperature measurement pointed to periodic temperature fluctuations of the SW, which exhibited attenuation and hysteresis characteristics. When the vertical flow velocity of GW was sufficiently large, an error in the accuracy of the Kerry model amplitude ratio was observed, regardless of the heat dispersion coefficient used. Under conditions of local GW recharge by SW and a heterogeneous permeability coefficient, the use of the amplitude ratio method is recommended to quantify the vertical GW flow rate in the HZ. [ABSTRACT FROM AUTHOR]

Background/Aims: VCP-interacting membrane selenoprotein (VIMP), an ER resident selenoprotein, is highly expressed in β-cells, however, the role of VIMP in β-cells has not been characterized. In this study, we studied the relationship between VIMP deficiency and β-cell survival in MIN6 insulinoma cells. Methods: To determine the role of VIMP in β-cells, lentiviral VIMP shRNAs were used to knock down (KD) expression of VIMP in MIN6 cells. Cell death was quantified by propidium iodide (PI) staining followed by flow cytometric analyses using a FACS Caliber and FlowJo software. Cell apoptosis and proliferation were determined by TUNEL assay and Ki67 staining, respectively. Cell cycle was analyzed after PI staining. Results: The results show that 1) VIMP suppression induces β-cell apoptosis, which is associated with a decrease in Bcl-xL, and the β-cell apoptosis induced by VIMP suppression can be inhibited by overexpression of Bcl-xL; 2) VIMP knockdown (KD) decreases cell proliferation and G1 cell cycle arrest by accumulating p27 and decreasing E2F1; 3) VIMP KD suppresses unfolded protein response (UPR) activation by regulating the IRE1α and PERK pathways; 4) VIMP KD increases insulin secretion. Conclusion: These results suggest that VIMP may function as a novel regulator to modulate β-cell survival, proliferation, cell cycle, UPR and insulin secretion in MIN6 cells. [ABSTRACT FROM AUTHOR]

Abstract As the most conserved branch of the unfolded protein response (UPR), the inositol-requiring enzyme 1a (IRE1a)/X-box binding protein 1 (XBP1) pathway plays crucial roles in cell survival and cell death by upregulating UPR-associated genes involved in protein entry into the endoplasmic reticulum (ER) and ER-associated degradation (ERAD). Selenoprotein S (SelS) is localized to the ER membrane and involved in ERAD. Although SelS plays an important role in restoring ER stress, the SelS-dependent protective mechanisms against cell death remain unclear. Here, using an inducible SelS knockdown (KD) 3T3-L1 cell model, we showed that SelS KD resulted adipocyte death, which was associated with imbalance of the Bcl-2 family members. Furthermore, SelS KD decreased spliced XBP1 (sXBP1), increased IRE1α and p -JNK, suggesting a role of SelS in the modulation of the IRE1α-sXBP1 pathway. Moreover, adipocyte death induced by SelS suppression can be inhibited by overexpression of sXBP1. Thus, it is proposed that SelS promotes cell survival through the IRE1α-XBP1 signaling pathway. [ABSTRACT FROM AUTHOR]

Endothelial dysfunction, partly induced by inflammatory mediators, is known to initiate and promote several cardiovascular diseases. Selenoprotein S (SelS) has been identified in endothelial cells and is associated with inflammation; however, its function in inflammation-induced endothelial dysfunction has not been described. We first demonstrated that the upregulation of SelS enhances the levels of nitric oxide and endothelial nitric oxide synthase in tumor necrosis factor- (TNF-) α-treated human umbilical vein endothelial cells (HUVECs). The levels of TNF-α-induced endothelin-1 and reactive oxygen species are also reduced by the upregulation of SelS. Furthermore, SelS overexpression blocks the TNF-α-induced adhesion of THP-1 cells to HUVECs and inhibits the increase in intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Moreover, SelS overexpression regulates TNF-α-induced inflammatory factors including interleukin-1β, interleukin-6, interleukin-8, and monocyte chemotactic protein-1 and attenuates the TNF-α-induced activation of p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways. Conversely, the knockdown of SelS with siRNA results in an enhancement of TNF-α-induced injury in HUVECs. These findings suggest that SelS protects endothelial cells against TNF-α-induced dysfunction by inhibiting the activation of p38 MAPK and NF-κB pathways and implicates it as a possible modulator of vascular inflammatory diseases. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the impact of dynamic changes in inflammation on atherosclerosis in short-duration type 2 diabetes after multifactorial intervention.Methods: In this randomized controlled study, a total of 150 type 2 diabetes patients who had a mean age of 49.8±7.3years, 51% male, with disease duration <1year and without evidence of atherosclerosis were randomized into an intensive intervention group (IG), in which patients received multiple risk factors intervention by the special project team and tried to reach the pre-determined intervention goals, and a conventional group (CG), in which patients received standard diabetes care by the clinic doctor. All patients recieved intervention study for 7 years, then underwent a 3-year observational follow-up study. The primary endpoints were occurrence of subclinical atherosclerosis, defined as the intima-media thickness of the common carotid artery (CC-IMT)≥1.0mm or formation of atherosclerosis plaques, and the occurrence of cardiovascular events.Results: 68 patients in IG and 65 patients in CG completed the 10-year study. The cumulative incidence of subclinical atherosclerosis was 30.7% vs 57.3% (IG vs CG, HR 0.36, 95% CI 0.22-0.60, P<0.0001) and that of cardiovascular events was 12.0% vs 22.7% (IG vs CG, HR 0.46, 95% CI 0.21-0.98, P=0.0516). High sensitivity C-reactive protein (hs-CRP) reduction from baseline to the 10-year follow-up was -1.54mg/L (IG) and -0.67mg/L (CG) with difference (IG minus CG) of -0.87mg/L(95% CI -0.72 to -1.02, P=0.008) and the natural logarithm of serum amyloid A (SAA) reduction was -4.04 (IG) and -1.44 (CG) with difference (IG minus CG) of -2.60 (95% CI -2.30 to -2.90, P=0.002). The decrease in general score of inflammatory markers (combination of hs-CRP and SAA) was independently associated with subclinical atherosclerosis (OR=0.65, P=0.045) and cardiovascular events (OR=0.60, P=0.042).Conclusions: Dynamic changes in inflammation act as an important factor that affects the occurrence of atherosclerosis in type 2 diabetes patients. Multifactorial intensive intervention can reduce systemic low-grade inflammation and delay the occurrence of atherosclerosis in short-duration type 2 diabetes. [ABSTRACT FROM AUTHOR]

N6-methyladenosine (m6A) is the most abundant mRNA modification. However, the role of m6A in regulating β-cell function is unknown. To address the functional role of METTL14, a key component of the m6A methyltransferase complex, in β-cells, we generated an METTL14 β-cell specific knockout mouse in adult MIP-CreERT transgenic mice. 4 weeks after tamoxifen treatment (100 mg/kg for 3 times every other day), the feeding glucose of βKO mice were 55.1% higher in βKO mice. βKO mice are also glucose intolerant. The AUC was increased by 54.7% in βKO mice (P<0.01). The fasting glucose were 307.5 ± 24.3 mg/dl in βKO mice and 219.0 ± 7.8 mg/dl in control mice (P<0.001). The response to insulin was similar between βKO and control mice. The feeding insulin levels in βKO mice were significantly decreased by 58.9% (P<0.01). The serum insulin levels from βKO mice were significantly lower at 0, 15 and 30 minutes after glucose challenge. In addition, the insulin secretion from βKO islets was less than 50% of control islets after incubated at 16.7 mM glucose. Surprisingly, β-cell mass in βKO mice was 55.9% higher than that in control mice (P<0.05). In addition, we did not detect β-cell death in βKO islets. However, β-cell proliferation in βKO islets was increased by 1.3-fold. To understand the molecular mechanism, we performed RNA-seq to detect the gene expression in βKO and control islets from male mice 8 weeks after tamoxifen treatment. Among 106 altered genes in βKO islets, 104 genes were upregulated (P<0.001) and 2 genes were downregulated. The genes response to ER stress such as Pdia4, Itpr1, Thbs1, Ire1α and Igfbp5 were among the top up-regulated genes. We applied m6A-seq in MIN6 cells and confirmed that Ire1α was modified by m6A in its last exon and 3' UTR region. We further showed that both mRNA and protein of Ire1α and spliced XBP-1 were significantly increased in βKO islets. In conclusion, METTL14 plays an important role in regulating insulin secretion, and METTL14 deficiency in β-cells induces diabetes by increasing ER stress. Disclosure: L. Men: None. J. Sun: None. D. Ren: None. Funding: National Institutes of Health (P30DK020595) [ABSTRACT FROM AUTHOR]

Endothelial dysfunction is an initiating key step for diabetic macrovascular complications, and it is closely related to the hemodynamic microenvironment in vivo. However, diabetic patients usually coexist with other cardiovascular risk factors, and the more powerful targeting strategy for protecting endothelium is still limited. Selenoprotein S (SelS) was found in our previous study that could increase vascular endothelial cells resistance to oxidative stress associated with protein kinase C α (PKCα). Thus, in this study, we constructed a diabetic vascular endothelial bionic microenvironment mimicking hyperglycemia and/or hyperlipidemia based on microfludic chip through modulating the concentration of medium glucose and oxidized low density lipoproteins. Our results showed that under diabetic vascular endothelial bionic microenvironment, the upregulation of SelS enhanced nitric oxide synthase (eNOS) expression and reduced endothelin-1 level in human aortic endothelial cells (HAECs), accompany with increase in cell viability and SOD1 and SOD2 activity, and decrease in ROS. Furthermore, SelS overexpression attenuated the activation of PKCα, which subsequently promoted the activation of PI3K/Akt/eNOS pathway. Conversely, the knockdown of SelS resulted in an enhancement of endothelial injury. These findings suggest that SelS could protect endothelial cells from oxidative stress injury under diabetic vascular endothelial bionic microenvironment through PKCα and PI3K/Akt/eNOS pathway. Our results offer a promising and biomimetic platform for investigation on endothelial protection, and provide evidence of SelS as potential novel target to treat diabetic macrovascular complications. Disclosure: S. Yu: None. Y. Zhong: None. L. Men: None. J. Yao: None. J. Du: None. Funding: National Natural Science Foundation of China (81570727) [ABSTRACT FROM AUTHOR]

The hyporheic zone is a transition zone for the exchange of matter and energy between surface water and subsurface water. The study of trends and sensitivities of bed hyporheic exchanges to the various influencing factors is of great significance. The surface−groundwater flow process was simulated using a multiphysics computational fluid dynamics (CFD) method and compared to previous flume experiments. Based on that, the single-factor effects of flow velocity (u), water depth (H), dune wave height (h), and bed substrate permeability (κ) on hyporheic exchange in the bed hyporheic zone were investigated. The sensitivity analysis of various factors (H, u, dune wavelength (L), h, bed substrate porosity (θ), κ, and the diffusion coefficient of solute molecules (Dm)) in the surface−subsurface water coupling model was done using orthogonal tests. The results indicated that u, h, and κ were positively related, whereas H was negatively related to hyporheic exchange. H and u showed large effects, whereas κ, Dm, and θ had moderate effects, and L and h showed small effects on hyporheic exchange. This study provides valuable references for the protection and recovery of river ecology. [ABSTRACT FROM AUTHOR]

The transport of materials and energy between rivers and riparian zones are driven by lateral hyporheic exchange and plays a vital role in regulating the ecological health of rivers. Owing to the limitations of models and methods, prior research has mainly focused on vertical hyporheic exchange in river systems. Combined with the collected riparian zone temperature and water level data, a 2D hydrothermal coupling model of the riparian zone was developed using the thermal conductivity model, and the fitting effects of the Lu et al. (2007) model and Su et al. (2016) model on temperature variations in riparian zone comparatively analyzed. Then, the dynamic variation characteristics of the riparian zone temperature and the lateral hyporheic exchange recharge pattern were investigated by the constructed models. The calibrated model could reasonably illustrate the variations in the riparian zone temperature, and the sensitivity analysis revealed that the hydraulic conductivity (Ks) is the most sensitive factor to the temperature variations. [ABSTRACT FROM AUTHOR]

As an environmental toxicant, arsenic exposure may cause insulin resistance (IR). Previous studies have shown that pyroptosis plays an important role in the occurrence and development of IR. Although gasdermin D (GSDMD) functions as an executor of pyroptosis, the relationship between GSDMD-mediated pyroptosis and hepatic IR remains unclear. Here, we observed that sodium arsenite (NaAsO 2) activated NOD-like receptors containing pyrin domain 3 (NLRP3) inflammasomes, promoted GSDMD activation, induced pyroptosis and hepatic IR, while GSDMD knockdown attenuated pyroptosis and hepatic IR caused by NaAsO 2. However, GSDMD interference did not affect NLRP3 activation. Ubiquitination modification is widely involved in protein regulation and intracellular signal transduction, and whether it regulates GSDMD and affects its degradation, and exerts effects on arsenic-induced pyroptosis remain unclear. We observed that NaAsO 2 reduced the K48- and K63-linked ubiquitination of GSDMD, thereby inhibiting its degradation through the ubiquitin-proteasome system (UPS) and the autophagy-lysosome pathway (ALP), causing GSDMD to accumulate and lyse into GSDMD-N, which promoted pyroptosis. In summary, we demonstrated that GSDMD participated in arsenic-induced hepatic IR. Moreover, NaAsO 2 reduced GSDMD ubiquitination and decreased its intracellular degradation, aggravating pyroptosis and hepatic IR. We have revealed the molecular mechanism underpinning arsenic-induced IR, and we provide potential solutions for the prevention and treatment of type 2 diabetes (T2D). [Display omitted] • The reduction of GSDMD would attenuate the arsenic-induced pyroptosis and insulin resistance. • Exposure to NaAsO 2 would reduce the ubiquitination level of GSDMD. • Ubiquitinated GSDMD would be degraded by ubiquitin-proteasome system and autophagy-lysosome pathway. [ABSTRACT FROM AUTHOR]

Glucolipid metabolism disorder in diabetes mellitus (DM) causes human endothelial injury and autophagy dysfunction is an important cause of endothelial dysfunction (ED). Selenoprotein S (SelS) could protect endothelium from oxidative stress, inflammatory responses, and apoptosis. This study assessed the effect of SelS on autophagy in glucolipid metabolic disorders and protection of the resulted vascular endothelial injury. The results showed that high glucose (HG), high oxidized low-density lipoprotein (HL), and HG combined with HL (HGL) could reduce viability of human aortic endothelial cells (HAECs), induce HAECs injury and increase SelS expression in a time-dependent manner. HG, HL, and HGL also initially induced autophagy but later reduced it in HAECs, while activity of the Akt/mTOR signaling was inhibited, especially in HGL culture of HAECs. SelS overexpression reduced the endothelial injury and autophagy and activated the Akt/mTOR signaling in HG, HL and HGL-cultured HAECs, compared to the control. Conversely, knockdown of SelS expression had the opposite effects on HAECs. In conclusion, SelS demonstrated a protective effect on endothelial injury induced by high glucose and/or ox-LDL and the underlying molecular events might be related to its regulation of HAECs autophagy by activating the Akt/mTOR signaling. SelS could be a potential intervention target in prevention and treatment of diabetic vascular complications. • Glucolipid metabolism disorder had a synergistic effect on endothelial injury. • Selenoprotein S could attenuate endothelial injury in HAECs. • Selenoprotein S inhibited human aortic endothelial cell autophagy. • Selenoprotein S regulated autophagy through Akt/mTOR signaling. [ABSTRACT FROM AUTHOR]

Endothelial dysfunction (ED) is a critical and initiating factor in the genesis of diabetic vascular complications whose occurrence and development is closely related to the complex intravascular microenvironment. However, currently, there is no dynamic model simulating the diabetic vascular endothelial microenvironment that can be used to investigate the mechanism underlying multifactor-induced ED. Here, we developed an integrated microfluidic chip as a new methodological platform to study vascular ED. Selenoprotein S (SELENOS) was found to be involved in the defense against oxidative stress-induced vascular endothelial injury in our previous studies. However, the regulatory signaling pathway underlying this process has not been described. With this chip, we demonstrated that multifactor-induced oxidative stress injury in human aortic endothelial cells (HAECs) has a synergistic effects and upregulates SELENOS expression. Subsequently, SELENOS was found to protect HAECs against multifactor-induced oxidative stress injury by regulating the PKCα/PI3K/Akt/eNOS pathway in the diabetic vascular endothelial microenvironment. Based on these data, our diabetic vascular chip provides a promising tool for studying vascular endothelial function, and SELENOS may be a novel target for prevention and treatment of diabetic macrovascular complications. • We constructed a diabetic vascular microfluidic chip to study the roles and mechanism of SELENOS in endothelial injury. • Multifactor-induced oxidative stress injury in HAECs has a synergistic effects and upregulates SELENOS expression. • SELENOS was found to protect HAECs against multifactor-induced oxidative stress injury via the PKCα/PI3K/Akt/eNOS pathway. [ABSTRACT FROM AUTHOR]

Background and Objective: Psychological insulin resistance (PIR), which refers to the reluctance of diabetic patients to use insulin, is a frequently encountered clinical issue. Needle-free injection (NFI) offers advantages in terms of expediting insulin absorption and mitigating adverse reactions related to injection. To evaluate the effects of subcutaneous injection of insulin aspart 30 with NFI on PIR and insulin dosage in patients with type 2 diabetes mellitus (T2DM)., Methods: Sixty-four patients with T2DM participated in this randomized, prospective, open, crossover study. Insulin aspart 30 was administered subcutaneously to each subject via QS-P NFI and Novo Pen 5 (NP) successively. The effects of NFI on PIR were analyzed. Differences in insulin dosage, glycemic variability, and injection safety were compared at similar levels of glycemic control., Results: After the administration of NFI, the insulin treatment attitude scale score decreased (53.7 ± 7.3 vs. 58.9 ± 10.7, p<0.001), the insulin treatment adherence questionnaire score increased (46.3 ± 4.9 vs. 43.8 ± 7.1, p<0.001), and the insulin treatment satisfaction questionnaire score increased (66.6 ± 10.5 vs. 62.4 ± 16.5, p<0.001). At the same blood glucose level, NFI required a smaller dosage of insulin aspart 30 compared with that of NP (30.42 ± 8.70 vs. 33.66 ± 9.13 U/d, p<0.001). There were no differences in glycemic variability indices (standard deviation, mean amplitude of glycemic excursion or coefficient of variation) between the two injection methods. Compared with NP, NFI did not increase the incidence of hypoglycemia (17.2% vs. 14.1%, p=0.774), and it decreased the incidence of induration (4.7% vs. 23.4%, p=0.002) and leakage (6.3% vs. 20.3%, p=0.022) while decreasing the pain visual analog scale score (2.30 ± 1.58 vs. 3.11 ± 1.40, p<0.001)., Conclusion: NFI can improve PIR in patients with T2DM and be used with a smaller dose of insulin aspart 30 while maintaining the same hypoglycemic effect., Clinical Trial Registration: https://www.chictr.org.cn/, identifier ChiCTR2400083658., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Men, Wang, Shi, Yin, Li, Zhou and Du.)

The induction of endoplasmic reticulum (ER) stress is associated with adipogenesis, during which the inositol-requiring enzyme 1 alpha (IRE1α)-X-box-binding protein 1 (XBP1) pathway is involved. Selenoprotein S (SelS), which is an ER resident selenoprotein, is involved in ER homeostasis regulation; however, little is known about the role of SelS in regulating adipogenesis. In vivo studies showed that SelS protein levels in white adipose tissue were increased in obese subjects and high-fat diet (HFD)-fed mice. Moreover, we identified that SelS protein levels increased in the early phase of adipogenesis and then decreased in the late phase during adipogenesis. Overexpression of SelS promoted adipogenesis. Conversely, knockdown (KD) of SelS resulted in the inhibition of adipogenesis, which was related to increasing cell death, decreased mitotic clonal expansion, and cell cycle G1 arrest. In vivo studies also showed that ER stress markers (p-IRE1α/IRE1α, XBP1s, and Grp78) were significantly increased with upregulating of SelS expression in subcutaneous and visceral adipose tissues in the obese subjects and HFD-fed mice. Furthermore, in SelS KD cells, the levels of Grp78 were increased and the levels of p-IRE1α/IRE1α were unchanged , but mRNA levels of spliced XBP1 (XBP1s) produced by IRE1α-mediated splicing were decreased, suggesting a role of SelS in the modulation of IRE1α-XBP1 pathway. Moreover, inhibition of adipogenesis by SelS suppression can be rescued by overexpression of XBP1s. Thus, SelS appears to function as a novel regulator of adipogenesis through the IRE1α-XBP1 signaling pathway.

Interleukin-8 (IL-8, also named CXCL8) binds to its receptors (CXCR1 and CXCR2) with subsequent recruitment of neutrophils and enhancement of their infiltration into inflamed sites, which exaggerates inflammation in many diseases. Recent studies have proposed that metabolic disorders can be attenuated by counteracting certain inflammatory signal pathways. In this study, we examined whether intervention with G31P, an antagonist of CXCL8, could attenuate tissue inflammation and development of metabolic disorders in db/db mice. The db/m and db/db mice were subcutaneously injected with G31P or equivalent normal saline once a day for 6 wk. The physical and metabolic parameters, glucose tolerance, insulin sensitivity, hepatic lipid accumulation, and inflammation markers were measured. G31P improved hepatic insulin sensitivity by modulating expression of genes related to gluconeogenesis and phosphorylated Akt levels. The expressions of several genes encoding proteins involved in de novo lipogenesis were decreased in G31P-treated db/db mice. Meanwhile, immune cell infiltration and cytokine release were attenuated in db/db mice with G31P treatment. G31P also improved the ratio of proinflammatory M1 and anti-inflammatory M2 macrophages. Furthermore, G31P ameliorates metabolic disturbances via inhibition of CXCR1 and CXCR2 pathways in db/db mice. These data suggest that the selective inhibition of CXC chemokines may have therapeutic effects on symptoms associated with obesity and diabetes.

Background: The mechanisms underlying diabetic encephalopathy are largely unknown, and no effective treatments are available. Catalpol has received much attention due to its numerous biological effects, especially in neuroprotective studies. The aim of this study was to investigate the effects of catalpol on cognitive functions in diabetic rats and the underlying mechanisms., Methods: A rat model of diabetes was established by streptozotocin injection, followed by intraperitoneal infusion of catalpol after 10 weeks. Two weeks later, the Morris water maze was used to test the spatial learning performance. Nissl staining was performed to evaluate the morphological changes in the hippocampus. Expression of protein kinase Cγ (PKCγ) and caveolin-1 (Cav-1) in the hippocampus were assessed by reverse transcription PCR and Western blotting. Activities of anti-oxidative enzymes such as glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and levels of malonaldehyde (MDA) were measured using commercial kits., Results: Significant hippocampal neuronal injury was observed in rats with streptozotocin-induced diabetes. Moreover, cognitive dysfunction was associated with markedly increased oxidative stress in the brain. Catalpol treatment significantly attenuated cognitive deficits, neuronal damage, and oxidative stress in the brain of diabetic rats. Biochemical analyses showed that catalpol reversed the down-regulation of PKCγ and Cav-1 expression in the diabetic rats., Conclusions: Spatial memory in diabetic rats is associated with the expression of PKCγ and Cav-1. Catalpol treatment markedly attenuated oxidative stress, reversed the alteration of PKCγ, Cav-1 and spatial memory deficits.