Transient receptor potential melastatin-like 7 (TRPM7) is a key player in various physiological and pathological processes. TRPM7 channel activity is regulated by different factors. The effects of ...cleavage of different domains on channel activity remain unknown. Here, we constructed several TRPM7 clones and explored the effects of truncating the mouse TRPM7 at different locations on the ion channel activity in two cell lines. We compared the clones' activity with the full-length TRPM7 and the native TRPM7 in transfected and untransfected cells. We also expressed fluorescently tagged truncated clones to examine their protein stability and membrane targeting. We found that truncating the kinase domain induced reduction in TRPM7 channel activity. Further truncations beyond the kinase (serine/threonine rich domain and/or coiled-coil domain) did not result in further reductions in channel activity. Two truncated clones lacking the TRP domain or the melastatin homology domain had a completely nonfunctional channel apparently due to disruption of protein stability. We identified the shortest structure of TRPM7 with measurable channel activity. We found that the truncated TRPM7 containing only S5 and S6 domains retained some channel activity. Adding the TRP domain to the S5-S6 resulted in a significant increase in channel activity. Finally, our analysis showed that TRPM7 outward currents are more sensitive to truncations than inward currents. Our data provide insights on the effects of truncating TRPM7 at different locations on the channel functions, highlighting the importance of different domains in impacting channel activity, protein stability, and/or membrane targeting.
Cytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the ...SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.
The interplay between gut microbiota (GM) and the metabolization of dietary components leading to the production of short-chain fatty acids (SCFAs) is affected by a range of factors including colonic ...pH and carbohydrate source. However, there is still only limited knowledge on how the GM activity and metabolite production in the gastrointestinal tract could be influenced by pH and the pH gradient increases along the colon.
Here we investigate the effect of pH gradients corresponding to levels typically found in the colon on GM composition and metabolite production using substrates inulin, lactose, galactooligosaccharides (GOS), and fructooligosaccharide (FOS) in an in vitro colon setup. We investigated 3 different pH regimes (low, 5.2 increasing to 6.4; medium, 5.6 increasing to 6.8 and high, 6.0 increasing to 7.2) for each fecal inoculum and found that colonic pH gradients significantly influenced in vitro simulated GM structure, but the influence of fecal donor and substrate was more pronounced. Low pH regimes strongly influenced GM with the decreased relative abundance of Bacteroides spp. and increased Bifidobacterium spp. Higher in vitro simulated colonic pH promoted the production of SCFAs in a donor- and substrate-dependent manner. The butyrate producer Butyricimonas was enriched at higher pH conditions, where also butyrate production was increased for inulin. The relative abundance of Phascolarctobacterium, Bacteroides, and Rikenellaceae also increased at higher colonic pH, which was accompanied by increased production of propionate with GOS and FOS as substrates.
Together, our results show that colonic substrates such as dietary fibres influence GM composition and metabolite production, not only by being selectively utilized by specific microbes, but also because of their SCFA production, which in turn also influences colonic pH and overall GM composition and activity. Our work provides details about the effect of the gradients of rising pH from the proximal to distal colon on fermenting dietary substrates in vitro and highlights the importance of considering pH in GM research.
The effect of dietary graded levels of Cyberlindnera jadinii yeast (C. jadinii) on growth performance, nutrient digestibility, and gut health of broilers was evaluated from 1 to 34 d of age. A total ...of 360 male broiler chicks were randomly allocated to 1 of 4 dietary treatments (6 replicate pens each) consisting of a wheat-soybean meal-based pelleted diet (Control or CJ0), and 3 diets in which 10% (CJ10), 20% (CJ20), and 30% (CJ30) of the crude protein were supplied by C. jadinii, by gradually replacing protein-rich ingredients. Body weight and feed intake were measured at d 1, 11, 22, and 32. Pellet temperature, durability, and hardness increased linearly (P < 0.05) with C. jadinii inclusion, with highest (P < 0.05) values for CJ30. Up until d 22, feed conversion ratio (FCR) was similar between treatments (P = 0.169). Overall, increasing C. jadinii inclusion linearly increased (P = 0.047) feed intake but had no effect on weight gain or mortality. FCR increased (P < 0.05) linearly with increasing C. jadinii inclusion but only birds fed CJ30 had a significantly poorer FCR compared to the Control. Ileal digestibility was not affected by C. jadinii inclusion, however, there was a significant linear decrease in crude protein and phosphorus, and a tendency for a decrease in fat digestibility. Apparent metabolizable energy (AME) decreased (P < 0.001) quadratically with increasing C. jadinii and was significantly lower in CJ30 compared to the Control. Ileal concentrations of volatile fatty acids (VFAs) were not affected by C. jadinii inclusion, but butyric acid and total VFAs were linearly and quadratically increased and were significantly higher in cecal digesta of birds fed CJ20 and CJ30. Increasing C. jadinii inclusion was associated with an increase (P < 0.05) in the relative abundance of lactobacillus in the ileum and cecum. In conclusion, C. jadinii yeast can supply up to 20% of the total dietary protein without negatively affecting performance, digestibility, or gut health of broilers. The potential confounding role of feed processing and C. jadinii cell wall components on broiler performance is discussed.
Display omitted
•PS showed anti-obesity effects on HFD-fed mice and regulated metabolic disorders.•The content of propionate showed an increasing trend in mice supplemented with PS.•Mice in the PS ...group exhibited an altered gut microbiota.•Increased S24-7 and Ruminococcus are associated with weight-reducing effects.
Obesity threatens human health worldwide, and mounting findings have found that gut microbiota (GM) changes induced by diet intervention influence its development. This study aims to investigate the anti-obesity effects and GM changes of propionylated high-amylose maize starch (PS) in C57BL/6J mice fed with high-fat diet (HFD). In our results, PS decreased the body weight of HFD-fed mice after 8 weeks and regulated the glucose stability and insulin resistance. High-amylose maize starch (HAMS) and PS regulated the serum lipid levels and inflammatory response. Moreover, PS yielded more propionate relative to HAMS, proving that introduced propionyl groups could be released in the colon. 16S rRNA results showed that PS altered GM with the increase of bacteria (S24-7 and Ruminococcus) and decrease of harmful genera, which is linked to the anti-obesity effect. Our results provide a reference for the design of functional dietary fibers inducing high propionate production and GM modulation.
In a tenfold-concentrated simulated body fluid, a strategy for rapid deposition of a biomimetic calcium phosphate layer on the scaffolds of electrospun collagen nanofiber membranes was developed. The ...aim of this study was to explore the effects of mineralization conditions and phosvitin (PV) on hydroxyapatite nucleation and growth. The mineralization model, the pH of the environment, and the deposition time were optimized. Scanning electron microscopy (SEM) images demonstrated that homogeneous and well-crystallized inorganic mineral layers were generated in the dynamic mineralization model system after incubating 3 h at pH 5.7. PV, which possesses the highest level of phosphorylation among egg proteins, was used as a model protein to investigate the contribution of PV in the mineralization process. The morphological structure and composition of the collagen/calcium phosphate composite nanofibers were also characterized by energy dispersive spectroscopy, scanning photoelectron spectrometer, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. XRD results showed the transformation process of mineralization materials from dicalcium phosphate dihydrate (DCPD) to HA through the changes of characteristic peaks at approximately 11° of DCPD and 31.8° of HA. 1.0 mg/mL. Phosvitin significantly promoted the phase transformation from DCPD to hydroxyapatite. High performance liquid chromatography results indicated that PV induced the mineralization rather than being the part of the hydroxyapatite. The minerals formed on electrospun collagen nanofiber membranes were identified to be from hydroxyapatite. These findings extended the potential application field of PV to biomimetic material.
Display omitted
•Propionylated high-amylose maize starches showed slow and similar fermentation rate.•Concentration of propionate increased gradually with increase of the DS values.•Propionyl groups ...remarkably promoted the relative abundance of the OTU30809 Roseburia.
Resistant starch (RS) acylated with propionate groups is of particular interest in terms of their capacity to deliver specific short-chain fatty acids (SCFAs) to the colon with health benefits. In the present study, we fabricated propionylated high-amylose maize starches with different degrees of substitution (DS), and monitored the in vitro human fecal fermentation profiles. Propionylated modification did not change the slow gas production properties of high-amylose maize starch throughout the whole fermentation period. The final concentration of propionate (13.68–21.10 mM) produced by propionylated starch fermentation enhanced gradually with increase of DS value, resulting from the release of introduced propionyl groups. Certain beneficial gut microbiota such as Roseburia, and Blautia were obviously promoted, suggesting that propionylated starch could regulate the composition of gut microbiota. The results may facilitate the design and manufacture of functional food products with the aim of improving colonic health.
Display omitted
•Individual Bacteroides-dominated enterotype did not influence gas production.•Introduced propionyl groups could be released during fermentation.•The relative abundance of Bacteroides ...was promoted for each individual.•Gut microbiota changes were related to the initial microbiota composition.
The concept of “enterotype” has been proposed to differentiate the gut microbiota between individual humans, and different dominant bacteria utilize fiber substrates with different fermentation properties and microbial changes. In this study, we made propionylated high-amylose maize starch and investigated both in vitro fecal fermentation properties and microbial responses by individual Bacteroides-dominated enterotype inocula. Propionyl group substitution of HAMS did not significantly change gas production profiles, suggesting that the gas production during fermentation is independent of propionylation. The final concentration of released propionate significantly increased (10.26–12.60 mM) as a function of propionylation degree, suggesting that the introduced propionyl groups can increase the concentration of short-chain fatty acids (SCFA) during colonic fermentation. At the genus level, Bacteroides was obviously promoted for all donors with the final abundance in the range of 0.1–0.24, indicating that propionylated high-amylose maize starch changed the structure and abundance of microbiota compared to unmodified starch. Besides, the non-metric dimensional scoring (NMDS) plots showed that those changes were related to the initial microbiota composition. The results may offer useful information for the design of personalized food products and relevant therapies at least within Bacteroides-dominated enterotype.
In the present study, intact potato cells as whole potato food model were isolated through soaking with mild acid and alkali solutions, followed by controlled hydrothermal treatment to reach 0–100% ...degree of gelatinization (DG). The morphological and structural changes of entrapped starch granules as well as in vitro starch digestion properties were investigated. Our results indicated that the changes of cell wall permeability induced by varied DG values dominated the in vitro starch digestion profiles of intact cells. The gelatinization of intracellular potato starch leads to cell wall expansion and high cell wall permeability, resulting in the accessibility changes of digestive enzymes to encapsulated starch substrates through cell wall barrier. This study suggests that starch digestibility of potato foods can be regulated through cell wall permeability induced by intracellular starch gelatinization degree.
Display omitted
•Inhibition effect of cell wall barrier to starch digestion decreased as a function of gelatinization degree.•α-Amylase showed a preferential hydrolysis of the intact cells filled with gelatinized potato starches.•Changes of cell wall barrier induced by various gelatinization degree values dominated starch digestion of intact cells.
Intracranial aneurysms (IA) can induce increased intracranial pressure, headache, and the development of nausea and vomiting if not treated in time, and failure to receive timely diagnosis and ...treatment can lead to disability or death. However, the efficacy and prognostic value of craniotomy and endovascular embolization in patients with IA remains a controversial topic. This meta-analysis systematically evaluated the efficacy of endovascular coiling versus cranial aneurysm clamping on the immediate postoperative outcome and prognosis of patients with IA. PubMed, EMBASE, and the Cochrane Library databases were searched for retrieval of relevant references. Literature was screened according to pre-defined inclusion and exclusion criteria, and data were extracted and assessed for quality. A total of 10 studies, including 2,654 cases, were included in the analysis. Among them, 1,313 cases underwent craniotomy clipping surgery (clip group), and 1,341 cases underwent endovascular coiling (coil group). The quality of the studies in 8 articles evaluated using the Newcastle-Ottawa Scale (NOS) was ≥6. Meta-analysis was conducted using Rev Man 5.3 and Stata 17 software. The results of meta-analysis showed that no significant difference in complete occlusion rate OR=1.76, 95% CI (0.78, 3.96), P=0.17 when comparing the clip and coil group. Compared to the clip group, the coil group had a better clinical short-term outcome OR=1.55, 95% CI (1.05, 2.27), P=0.03, but an increased rate of postoperative residual or recurrence OR=0.40, 95% CI (0.17, 0.91), P=0.03. In addition, there were no significance differences identified in terms of complications, including the rates of postoperative rebleeding OR=1.60, 95% CI (0.97, 2.63), P=0.07, ischemic stroke OR=1.12, 95% CI (0.45, 2.79), P=0.81, and cerebral vasospasm OR=0.90, 95% CI (0.13, 6.03), P=0.91. Subsequently, we conducted experimental sequence analysis for each indicator, and the results were consistent with the results of meta-analysis. According to the recent clinical prognosis, a funnel plot was constructed, showing significant asymmetry on both sides, indicating some publication bias. However, the results of Begg's test with P=0.734 and Egger's test with P=0.633 suggest no significant publication bias. In general, endovascular coiling and microsurgical clipping appear to be equally effective in achieving vascular occlusion. Endovascular coiling may be more effective in improving the short-term clinical outcomes for patients. However, this approach may increase the rate of postoperative residual issue or recurrence.
PDF
