A cyclic dipeptide for salinity stress alleviation and the trophic flexibility of endophyte provide insights into saltmarsh plant-microbe interactions.

In response to climate change, the nature of endophytes and their applications in sustainable agriculture have attracted the attention of academics and agro-industries. This work focused on the endophytic halophiles of the endangered Taiwanese salt marsh plant, Bolboschoenus planiculmis, and evaluated the functions of these isolates through in planta salinity stress alleviation assay using Arabidopsis. The endophytic strain Priestia megaterium BP01R2, which can promote plant growth and salinity tolerance, was further characterized through multi-omics approaches. The transcriptomics results suggested that BP01R2 could function by tuning hormone signal transduction, energy-producing metabolism, multiple stress responses, etc. In addition, the cyclodipeptide cyclo(L-Ala-Gly), which was identified by metabolomics analysis, was confirmed to contribute to the alleviation of salinity stress in stressed plants via exogenous supplementation. In this study, we used multi-omics approaches to investigate the genomics, metabolomics, and tropisms of endophytes, as well as the transcriptomics of plants in response to the endophyte. The results revealed the potential molecular mechanisms underlying the occurrence of biostimulant-based plant-endophyte symbioses with possible application in sustainable agriculture.

CuCS/Cur composite wound dressings promote neuralized skin regeneration by rebuilding the nerve cell "factory" in deep skin burns.

Regenerating skin nerves in deep burn wounds poses a significant clinical challenge. In this study, we designed an electrospun wound dressing called CuCS/Cur, which incorporates copper-doped calcium silicate (CuCS) and curcumin (Cur). The unique wound dressing releases a bioactive Cu2+-Cur chelate that plays a crucial role in addressing this challenge. By rebuilding the "factory" (hair follicle) responsible for producing nerve cells, CuCS/Cur induces a high expression of nerve-related factors within the hair follicle cells and promotes an abundant source of nerves for burn wounds. Moreover, the Cu2+-Cur chelate activates the differentiation of nerve cells into a mature nerve cell network, thereby efficiently promoting the reconstruction of the neural network in burn wounds. Additionally, the Cu2+-Cur chelate significantly stimulates angiogenesis in the burn area, ensuring ample nutrients for burn wound repair, hair follicle regeneration, and nerve regeneration. This study confirms the crucial role of chelation synergy between bioactive ions and flavonoids in promoting the regeneration of neuralized skin through wound dressings, providing valuable insights for the development of new biomaterials aimed at enhancing neural repair.

Hyperbaric Lidocaine Aggravates Diabetic Neuropathic Pain by Targeting p38 MAPK/ERK and PINK1/Parkin-Mediated Mitophagy Signaling Pathway.

BACKGROUND: Diabetic neuropathic pain (DNP) is a complication of diabetes mellitus (DM). Hyperbaric lidocaine (HL), a local anesthetics drug, has neurotoxicity. The present study aims to study the effect and molecular mechanisms of HL on spinal nerve injury in DNP. METHODS: The DNP rat model was established through a high-fat-glucose diet in combination with Streptozotocin (STZ) administration. SB203580 and PD98059 were utilized to inhibit p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK). The mechanical paw withdrawal threshold (PWT) and the thermal paw withdrawal latency (PWL) were tested to evaluate rats' mechanical allodynia and thermal hyperalgesia. Hematoxylin-eosin (H&E) and terminal deoxynucleotidyltransferase-mediated dUTP nick-end Labeling (TUNEL) staining were performed to evaluate the pathological changes and neuron apoptosis in spinal cord tissues of L4-5. Western blotting analysis and reverse transcription-polymerase chain reaction (RT-qPCR) assay were used to measure the levels of proteins and mRNAs, respectively. RESULTS: PWT and PWL were decreased in DNP rats with serious spinal nerve injury. HL administration downregulated the PWT and PWL and aggravated spinal nerve injury in DNP rats, but isobaric lidocaine had no effects on these changes. Meanwhile, p38 MAPK/ERK signaling and PTEN-induced kinase 1 (PINK1)-mediated mitophagy were activated in DNP, which was enhanced by HL but not isobaric lidocaine. Blocking p38 MAPK/ERK signaling could effectively attenuate HL-induced spinal nerve injury and inhibit mitophagy. CONCLUSION: In summary, HL can aggravate spinal cord tissue damage in DNP rats by inducing PINK1-mediated mitophagy via activating p38 MAPK/ERK signaling. Our data provide a novel insight that supports the potential role of p38 MAPK/ERK signaling in acting as a therapeutic target for HL-induced neurotoxicity.

Study on the correlation of supplementation with L-citrulline on the gastrointestinal flora and semen antifreeze performance of ram.

Introduction: Cryopreservation of semen can give full play to the reproductive advantages of male animals. However, in actual production, due to the poor frost resistance of sheep semen and the low conception rate, the promotion of sheep frozen semen is greatly hindered. Therefore, it is urgent to improve the frost resistance of semen to improve the quality of frozen semen. At present, most studies on improving the quality of frozen semen are based on the improvement of semen dilutions, and few studies on improving the freezing resistance of ram semen by feeding functional amino acids. Methods: Therefore, 24 Turpan black rams were divided into high antifreeze group (HF) and a low antifreeze group (LF) Each of these groups was further randomly divided into control and experimental subgroups. The control subgroup was fed a basal diet, while the experimental subgroup received an additional 12 g/d of L-Cit supplementation based on the control group for a duration of 90 days. Results: The results showed that Following L-Cit supplementation, the experimental group demonstrated significantly elevated sperm density and VSL (Velocity of straight line), T-AOC, GSH-Px, and NO levels in fresh semen compared to the control group (P < 0.01). After thawing, the experimental group exhibited significantly higher levels of T-AOC, GSH-Px, and NO compared to the control group (P < 0.01). Additionally, the HFT group, after thawing frozen semen, displayed significantly higher HK1 protein expression compared to the control group. The number of spermatogonia, spermatocytes, and sperm cells in the HFT group was significantly higher than that in the HFC group. Moreover, 16S rRNA sequence analysis showed that Candidatus_Saccharimonas, Staphylococcus, Weissella, succinivbrionaceae_UcG_002, and Quinella were significantly enriched in the rumen of the HFT group, while Ureaplasma was significantly enriched in the HFC group. In the duodenum, Clostridiales_bacterium_Firm_14, Butyrivibrio, and Prevotellaceae_NK3831_group were significantly enriched in the HFT group, whereas Desulfovibrio and Quinella were significantly enriched in the HFC group. Discussion: Under the conditions employed in this study, L-Cit supplementation was found to enhance the intestinal flora composition in rams, thereby improving semen quality, enhancing the antifreeze performance of semen, and promoting the development of testicular spermatogenic cells.

Methionine-choline deficient diet deteriorates DSS-induced murine colitis through disturbance of gut microbes and infiltration of macrophages.

Ulcerative colitis (UC) is associated with changed dietary habits and mainly linked with the gut microbiota dysbiosis, necroptosis of epithelial cells, and mucosal ulcerations. Liver dysfunction and abnormal level of liver metabolism indices were identified in UC patients, suggesting a close interaction between gut and liver disorders. Methionine-choline deficient diet (MCD) has been shown to induce persistent alterations of gut microbiota and metabolome during hepatitis. In this study we further explored the disease phenotypes in UC patients and investigated whether MCD functioned as a trigger for UC susceptibility. After assessing 88 serum specimens from UC patients, we found significant liver dysfunction and dyslipidemia including abnormal ALT, AST, TG, TC, LDL-c and HDL-c. Liver dysfunction and dyslipidemia were confirmed in DSS-induced colitis mice. We fed mice with MCD for 14 days to cause mild liver damage, and then treated with DSS for 7 days. We found that MCD intake significantly exacerbated the pathogenesis of mucosal inflammation in DSS-induced acute, progressive, and chronic colitis, referring to promotion of mucosal ulcers, colon shortening, diarrhea, inflammatory immune cell infiltration, cytokines release, and abnormal activation of inflammatory macrophages in colon and liver specimens. Intraperitoneal injection of clodronate liposomes to globally delete macrophages dramatically compromised the pathogenesis of MCD-triggering colitis. In addition, MCD intake markedly changed the production pattern of short-chain fatty acids (SCFAs) in murine stools, colons, and livers. We demonstrated that MCD-induced colitis pathogenesis largely depended on the gut microbes and the disease phenotypes could be transmissible through fecal microbiota transplantation (FMT). In conclusion, this study supports the concept that intake of MCD predisposes to experimental colitis and enhances its pathogenesis via modulating gut microbes and macrophages in mice.

The virtual staining method by quantitative phase imaging for label free lymphocytes based on self-supervised iteration cycle-consistent adversarial networks.

Quantitative phase imaging (QPI) provides 3D structural and morphological information for label free living cells. Unfortunately, this quantitative phase information cannot meet doctors' diagnostic requirements of the clinical "gold standard," which displays stained cells' pathological states based on 2D color features. To make QPI results satisfy the clinical "gold standard," the virtual staining method by QPI for label free lymphocytes based on self-supervised iteration Cycle-Consistent Adversarial Networks (CycleGANs) is proposed herein. The 3D phase information of QPI is, therefore, trained and transferred to a kind of 2D "virtual staining" image that is well in agreement with "gold standard" results. To solve the problem that unstained QPI and stained "gold standard" results cannot be obtained for the same label free living cell, the self-supervised iteration for the CycleGAN deep learning algorithm is designed to obtain a trained stained result as the ground truth for error evaluation. The structural similarity index of our virtual staining experimental results for 8756 lymphocytes is 0.86. Lymphocytes' area errors after converting to 2D virtual stained results from 3D phase information are less than 3.59%. The mean error of the nuclear to cytoplasmic ratio is 2.69%, and the color deviation from the "gold standard" is less than 6.67%.

Imaging the intracellular refractive index distribution (IRID) for dynamic label-free living colon cancer cells via circularly depolarization decay model (CDDM).

Label-free detection of intracellular substances for living cancer cells remains a significant hurdle in cancer pathogenesis research. Although the sensitivity of light polarization to intracellular substances has been validated, current studies are predominantly focused on tissue lesions, thus label-free detection of substances within individual living cancer cells is still a challenge. The main difficulty is to find specific detection methods along with corresponding characteristic parameters. With refractive index as an endogenous marker of substances, this study proposes a detection method of intracellular refractive index distribution (IRID) for label-free living colon cancer (LoVo) cells. Utilizing the circular depolarization decay model (CDDM) to calculate the degree of circular polarization (DOCP) modulated by the cell allows for the derivation of the IRID on the focal plane. Experiments on LoVo cells demonstrated the refractive index of single cell can be accurately and precisely measured, with precision of 10-3 refractive index units (RIU). Additionally, chromatin content during the interphases (G1, S, G2) of cell cycle was recorded at 56.5%, 64.4%, and 71.5%, respectively. A significantly finer IRID can be obtained compared to the phase measurement method. This method is promising in providing a dynamic label-free intracellular substances detection method in cancer pathogenesis studies.

Dynamic three-dimensional deformation measurement by polarization-multiplexing of full complex amplitude.

This paper provides an extensive discussion of a complex amplitude-based dynamic three-dimensional deformation measurement method, in which the phase and amplitude of the speckle field are used for out-of-plane and in-plane deformation calculation respectively. By determining the optimal polarization states of the speckle field and reference field from the comprehensive analysis of measurement mathematical model in the principle of polarization multiplexing, the 3-step phase-shifting interferograms and one speckle gram can be directly recorded by a polarization camera in a single shot. The out-of-plane deformation would be recovered from the subtraction of speckle phases that are demodulated by a special least square algorithm; speckle gram with improved quality is offered for correlation computation to obtain in-plane deformation. The advancement and significance of the optimized strategy are intuitively demonstrated by comparing the measurement accuracy under different combinations of polarization states. Finally, the dynamic thermal deformation experiment reveals the potential in practical real-time applications.

Simultaneous size and defect control of metal-organic framework by deep eutectic solvent for efficient perfluoroalkyl substances adsorption: Delving into mechanism.

This study reports an environment-friendly protocol to prepare a metal-organic framework (MOF) with simultaneously controlled particle size and open metal site for adsorption removal of perfluoroalkyl substances (PFASs). The successful preparation of UiO-66 with defect and crystal size modulation was achieved using a green and straightforward method, adjusting the components and molar ratios of ammonium salt/glycolic acid deep eutectic solvents (DESs). The corresponding modulation mechanism primarily relied on the combined regulation of the deprotonation and competitive coordination abilities of the eutectic solvent components. The adsorption process was thoroughly examined using spectral analyses, adsorption behavior profiling, and ab initio molecular dynamics simulations. The results revealed that PFAS adsorption is driven by combined capturing effects, such as CF-π, acid/base coordination, C-F⋯Zr, hydrogen bonding, and hydrophobic interactions. Our findings were not thus that the smaller the crystal size of MOF and the higher the defect concentration in the material, the better the PFAS adsorption performance. The result demonstrated the combined effect of these adsorbent features on PFAS mixtures. Furthermore, they revealed unique differences in sorption properties between these targets with different carbon chain lengths. Extensive defects in DES-based UiO-66 led to larger pores, increasing the availability of many adsorption sites and aiding in PFAS adsorption and diffusion. Nevertheless, the surplus of larger pores in the substance increased the competitive adsorption, reducing the total quantity of PFASs absorbed. Furthermore, various interactions and a less restrictive configuration increased the contact of functional groups with adsorbates, substantially enhancing the adsorption. This study investigates the basic questions about how PFAS molecules are adsorbed on DES-based MOFs and the relationship among the structure, properties, and performance to improve the efficiency of this novel adsorbent.

Ammonia oxidation by in-situ chloride electrolysis in etching wastewater of semiconductor manufacturing using RuSnOx/Ti electrode: Effect of plating mode and metal ratio.

The indirect chloride-mediated ammonia oxidation encounters challenges in maintaining the effectiveness of metal oxide anodes when treating wastewaters with complex compositions. This study aims to develop a highly stable anode with RuO2-SnO2 coatings for treating an etching effluent from semiconductor manufacturing, which majorly contains NH3 and organic compounds. The RuSnOx/Ti electrode was synthesized using wet impregnation and calcination processes. The metal oxide configuration on Ti plate substrate was tuned by varying the step-dipping process in RuCl3 and SnCl4 baths. A 10-day continuous-flow electrolysis was conducted for studying the ammonia removal and chlorine yield under variable conditions, including detention, pH, current density, and initial ammonia and chloride concentrations. In the RuSnOx coatings, the configuration comprising RuO2 nanorods as the surface layer and an intermediate layer of SnO2 crystallites (by plating Ru3+ for three times to cover one Sn4+ layer, denoted as the Ru3Sn/Ti electrode) exhibited the best durability for acid washing, along with relatively high Faradaic efficiency and low energy consumption. To further improve the treatability of real wastewater (NH3-N = 634 mg L-1, chemical oxygen demand (COD) = 6700 mg L-1, Cl- = 2000 mg L-1, pH 11), the duel-cell electrolyzers were constructed in series under a current density of 30 mA cm-2 and 45 min detention. Ultimately, removals of NH3 and COD reached 95.8% and 76.3%, respectively, with successful limitation of chloramine formation.

Longitudinal evaluation of adverse events due to steroid use in primary immune thrombocytopenia: A population-based study.

This study aimed to investigate the association between the steroid use patterns and the risk of AEs in patients with primary immune thrombocytopenia (ITP). A total of 2691 newly diagnosed adults with ITP between 2011 and 2018 were identified from the National Health Insurance Research Database in Taiwan, and the date of first steroid use was defined as the index date. Post-index steroid use was calculated on a 90-day basis as a time-dependent variable and categorized by the average prednisolone-equivalent daily dose (<10 mg vs. ≥10 mg) and intensity (medication possession ratio <80% vs. ≥80%). Patients were followed up for 1 year from the index date for acute AE events, while chronic AEs were assessed until death, or end of 2019. Compared to patients with low-dose+low-intensity steroid use, those with high-dose+high-intensity steroid use were associated with a higher risk of acute AE (adjusted incident rate ratio [aIRR]: 1.57, 95% confidence interval [CI]: 1.38-1.78, p < 0.01) and chronic AE (aIRR: 1.26, 95% CI: 1.08-1.47, p < 0.01). Metabolic/endocrine and ophthalmologic disorders demonstrated the strongest correlation with a high dose and intensity. The joint effect of steroid dose and intensity was observed in patients with ITP, and the findings suggest that steroids should be used carefully.

DLP Fabrication of Multiple Hierarchical Biomimetic GelMA/SilMA/HAp Scaffolds for Enhancing Bone Regeneration.

Severe bone defects resulting from trauma and diseases remain a persistent clinical challenge. In this study, a hierarchical biomimetic microporous hydrogel composite scaffold was constructed by mimicking the hierarchical structure of bone. Initially, gelatin methacrylamide (GelMA) and methacrylic anhydride silk fibroin (SilMA) were synthesized, and GelMA/SilMA inks with suitable rheological and mechanical properties were prepared. Biomimetic micropores were then generated by using an aqueous two-phase emulsification method. Subsequently, biomimetic microporous GelMA/SilMA was mixed with hydroxyapatite (HAp) to prepare biomimetic microporous GelMA/SilMA/HAp ink. Hierarchical biomimetic microporous GelMA/SilMA/HAp (M-GSH) scaffolds were then fabricated through digital light processing (DLP) 3D printing. Finally, in vitro experiments were conducted to investigate cell adhesion, proliferation, and inward migration as well as osteogenic differentiation and vascular regeneration effects. In vivo experiments indicated that the biomimetic microporous scaffold significantly promoted tissue integration and bone regeneration after 12 weeks of implantation, achieving 42.39% bone volume fraction regeneration. In summary, this hierarchical biomimetic microporous scaffold provides a promising strategy for the repair and treatment of bone defects.

Hydrogel dressings with intrinsic antibiofilm and antioxidative dual functionalities accelerate infected diabetic wound healing.

Chronic wounds are often infected with biofilm bacteria and characterized by high oxidative stress. Current dressings that promote chronic wound healing either require additional processes such as photothermal irradiation or leave behind gross amounts of undesirable residues. We report a dual-functionality hydrogel dressing with intrinsic antibiofilm and antioxidative properties that are synergistic and low-leaching. The hydrogel is a crosslinked network with tethered antibacterial cationic polyimidazolium and antioxidative N-acetylcysteine. In a murine diabetic wound model, the hydrogel accelerates the closure of wounds infected with methicillin-resistant Staphylococcus aureus or carbapenem-resistant Pseudomonas aeruginosa biofilm. Furthermore, a three-dimensional ex vivo human skin equivalent model shows that N-acetylcysteine promotes the keratinocyte differentiation and accelerates the re-epithelialization process. Our hydrogel dressing can be made into different formats for the healing of both flat and deep infected chronic wounds without contamination of the wound or needing other modalities such as photothermal irradiation.

Diagnostic efficacy of combining diffusion-weighted magnetic resonance imaging with serum Mucin 1, Mucin 13, and Mucin 16 in distinguishing borderline from malignant epithelial ovarian tumors.

AIMS: To enhance ovarian tumor diagnosis beyond conventional methods, this study explored combining diffusion-weighted magnetic resonance imaging (DWI-MRI) and serum biomarkers (Mucin 1 [MUC1], MUC13, and MUC16) for distinguishing borderline from malignant epithelial ovarian tumors. METHODS: A total of 126 patients, including 71 diagnosed with borderline (BEOTs) and 55 with malignant epithelial ovarian tumors (MEOTs), underwent preoperative DWI-MRI. Region of interest (ROI) was manually drawn along the solid component's boundary of the largest tumor, focusing on areas with potentially the lowest apparent diffusion coefficient (ADC). For entirely cystic tumors, a free-form ROI enclosed the maximum number of septa while targeting the lowest ADC. Serum biomarkers were determined using enzyme-linked immunosorbent assay. RESULTS: Basic morphological traits proved inadequate for malignancy diagnosis, warranting this investigation. BEOTs had an ADC mean of (1.670 ± 0.250) × 103 mm2 /s, while MEOTs had a lower ADC mean of (1.332 ± 0.481) × 103 mm2 /s, with a sensitivity of 63.6% and specificity of 90.1%. Median MUC1 (167.0 U/mL vs. 87.3 U/mL), MUC13 (12.44 ng/mL vs. 7.77 ng/mL), and MUC16 (180.6 U/mL vs. 36.1 U/mL) levels were higher in MEOTs patients. The biomarker performance was: MUC1, sensitivity 50.9%, specificity 100%; MUC13, sensitivity 56.4%, specificity 78.9%; MUC16, sensitivity 83.64%, specificity 100%. Combining serum biomarkers and ADC mean resulted in a sensitivity of 96.4% and specificity of 100%. CONCLUSION: The integration of DWI-MRI with serum biomarkers (MUC1, MUC13, and MUC16) achieves exceptional diagnostic accuracy, offering a powerful tool for the precise differentiation between borderline and malignant epithelial ovarian tumors.

Adsorption of perfluoroalkyl substances on deep eutectic solvent-based amorphous metal-organic framework: Structure and mechanism.

Perfluoroalkyl substances (PFASs) are a class of emerging organic pollutants characterized by high toxicity, environmental persistence, and widespread detection in water sources. The removal of PFASs from water is a matter of global concern, given their detrimental impact on both the environment and public health. Many commonly used PFAS adsorbents demonstrate limited adsorption capacities and/or slow adsorption kinetics. Therefore, there is an urgent need for the development of efficient adsorbents. For the first time, this work systematically investigated the performance of a deep eutectic solvent (DES)-based amorphous metal-organic framework (MOF) for the adsorption of PFASs with different carbon-chain lengths under the state of the mixture in aquatic environments. The adsorption mechanism was probed by a suite of adsorption kinetics studies, adsorption isotherm profiling, spectral characterization, and ab initio molecular dynamics (AIMD) simulations, revealing that PFAS adsorption is driven by synergistic capturing effects including acid/base coordination, CF-π (carbon-fluorine-π), hydrogen bonding, and hydrophobic interactions. Furthermore, the adsorption processes of short-chain and long-chain targets were found to involve different rate-controlling steps and interaction sites. Hydrophobic interactions facilitated the swift arrival of long-chain PFASs at the coordinatively interacting sites between carboxyl termini and Lewis acid Zr unsaturated sites, thanks to their lower reaction barriers. On the other hand, the adsorption of short-chain PFASs primarily relied on a Zr hydroxyl-based ligand exchange force, which would take place at Brønsted acid sites. The existence of massive structural disorder in amorphous UiO-66 led to the development of larger pores, thus improving the accessibility of abundant adsorption sites and facilitating adsorption and diffusion. The presence of multiple types of interactions and flexible structure in defect-rich amorphous UiO-66 significantly increased the exposure of functional groups to the adsorbates. Additionally, this material possessed outstanding regeneration efficiency and outperformed other MOF-based adsorbents with high affinity for targets. It enhances our understanding of the adsorption performances and mechanisms of amorphous materials toward PFASs, thereby paving the way for designing more efficient PFAS adsorbents.

Revisiting the Role of Valeric Acid in Manipulating Ulcerative Colitis.

BACKGROUND: Ulcerative colitis (UC) is characterized by a complicated interaction between mucosal inflammation, epithelial dysfunction, abnormal activation of innate immune responses, and gut microbiota dysbiosis. Though valeric acid (VA), one type of short-chain fatty acids (SCFAs), has been identified in other inflammatory disorders and cancer development, the pathological role of VA and underlying mechanism of VA in UC remain under further investigation. METHODS: Studies of human clinical specimens and experimental colitis models were conducted to confirm the pathological manifestations of the level of SCFAs from human fecal samples and murine colonic homogenates. Valeric acid-intervened murine colitis and a macrophage adoptive transfer were applied to identify the underlying mechanisms. RESULTS: In line with gut microbiota dysfunction in UC, alteration of SCFAs from gut microbes were identified in human UC patients and dextran sodium sulfate -induced murine colitis models. Notably, VA was consistently negatively related to the disease severity of UC, the population of monocytes, and the level of interluekin-6. Moreover, VA treatment showed direct suppressive effects on lipopolysaccharides (LPS)-activated human peripheral blood mononuclear cells and murine macrophages in the dependent manner of upregulation of GPR41 and GPR43. Therapeutically, replenishment of VA or adoptive transfer with VA-modulated macrophages showed resistance to dextran sodium sulfate-driven murine colitis though modulating the production of inflammatory cytokine interleukin-6. CONCLUSIONS: In summary, the research uncovered the pathological role of VA in modulating the activation of macrophages in UC and suggested that VA might be a potential effective agent for UC patients.

The study collectively indicated that valeric acid (VA) was consistently negatively related to the disease severity of UC, and hypofunction of macrophage driven by VA impeded the progression of UC.

Calcium-gated potassium channel blockade via membrane-facing fenestrations.

Quaternary ammonium blockers were previously shown to bind in the pore to block both open and closed conformations of large-conductance calcium-activated potassium (BK and MthK) channels. Because blocker entry was assumed through the intracellular entryway (bundle crossing), closed-pore access suggested that the gate was not at the bundle crossing. Structures of closed MthK, a Methanobacterium thermoautotrophicum homolog of BK channels, revealed a tightly constricted intracellular gate, leading us to investigate the membrane-facing fenestrations as alternative pathways for blocker access directly from the membrane. Atomistic free energy simulations showed that intracellular blockers indeed access the pore through the fenestrations, and a mutant channel with narrower fenestrations displayed no closed-state TPeA block at concentrations that blocked the wild-type channel. Apo BK channels display similar fenestrations, suggesting that blockers may use them as access paths into closed channels. Thus, membrane fenestrations represent a non-canonical pathway for selective targeting of specific channel conformations, opening novel ways to selectively drug BK channels.

Ochratoxin A Induces Renal Cell Ferroptosis by Disrupting Iron Homeostasis and Increasing ROS.

Mycotoxin ochratoxin A (OTA) is a critical food safety concern due to its nephron-toxic effects and is detected in a wide range of food and feedstuffs. OTA nephrotoxicity is related to oxidative stress and damage. However, the mediator(s) of the excessive oxidative stress is unclear. The current study used human kidney cell lines to investigate whether and how intracellular iron contributed to OTA-induced ROS accumulation and how OTA-induced iron-dependent ferroptotic cell death. Our results showed that OTA treatment affected the cell viability and induced the typical characteristics of cell ferroptosis. Furthermore, gene and protein expression results indicated that OTA disrupted iron homeostasis by upregulating the expression levels of iron importer TFR1 and FTH, while downregulating the expression level of iron exporter FPN and dramatically increasing its negative regulator Hepcidin. The changes were consistent with the induction of intracellular iron accumulation and elevated levels of oxidative stress and lipid peroxidation. Additionally, co-treatment with OTA and an iron chelator significantly improved cell viability, reduced cellular total iron and ROS, and reversed OTA-induced changes in iron metabolism gene expression levels. Interestingly, the addition of a ROS scavenger also reversed cell death and changes in mRNA and protein expression levels of iron metabolism genes but to a lesser degree than that of the iron-chelating agent. Our results revealed that OTA induced ferroptosis in renal cells by disrupting iron homeostasis and increasing ROS.

pH-Responsive Wound Dressing Based on Biodegradable CuP Nanozymes for Treating Infected and Diabetic Wounds.

Nanozymes, emerging nanomaterials for wound healing, exhibit enzyme-like activity to modulate the levels of reactive oxygen species (ROS) at wound sites. Yet, the solo regulation of endogenous ROS by nanozymes often falls short, particularly in chronic refractory wounds with complex and variable pathological microenvironments. In this study, we report the development of a multifunctional wound dressing integrating a conventional alginate (Alg) hydrogel with a newly developed biodegradable copper hydrogen phosphate (CuP) nanozyme, which possesses good near-infrared (NIR) photothermal conversion capabilities, sustained Cu ion release ability, and pH-responsive peroxidase/catalase-mimetic catalytic activity. When examining acute infected wounds characterized by a low pH environment, the engineered Alg/CuP composite hydrogels demonstrated high bacterial eradication efficacy against both planktonic bacteria and biofilms, attributed to the combined action of catalytically generated hydroxyl radicals and the sustained release of Cu ions. In contrast, when applied to chronic diabetic wounds, which typically have a high pH environment, these composite hydrogels exhibit significant angiogenic performance. This is driven by the provision of catalytically generated dissolved oxygen and a beneficial supplement of Cu ions released from the degradable CuP nanozyme. Further, a mild thermal effect induced by NIR irradiation amplifies the catalytic activities and bioactivity of Cu ions, thereby enhancing the healing process of both infected and diabetic wounds. Our study validates that the synergistic integration of photothermal effects, catalytic activity, and released Cu ions can concurrently yield high antibacterial efficiency and tissue regenerative activity, rendering it highly promising for various clinical applications in wound healing.

The L27 Domain of MPP7 enhances TAZ-YY1 Cooperation to Renew Muscle Stem Cells.

Stem cells regenerate differentiated cells to maintain and repair tissues and organs. They also replenish themselves, i.e. self-renewal, for the regenerative process to last a lifetime. How stem cells renew is of critical biological and medical significance. Here we use the skeletal muscle stem cell (MuSC) to study this process. Using a combination of genetic, molecular, and biochemical approaches, we show that MPP7, AMOT, and TAZ/YAP form a complex that activates a common set of target genes. Among these targets, Carm1 can direct MuSC renewal. In the absence of MPP7, TAZ can support regenerative progenitors and activate Carm1 expression, but not to a level needed for self-renewal. Facilitated by the actin polymerization-responsive AMOT, TAZ recruits the L27 domain of MPP7 to up-regulate Carm1 to the level necessary to drive MuSC renewal. The promoter of Carm1, and those of other common downstream genes, also contain binding site(s) for YY1. We further demonstrate that the L27 domain of MPP7 enhances the interaction between TAZ and YY1 to activate Carm1. Our results define a renewal transcriptional program embedded within the progenitor program, by selectively up-regulating key gene(s) within the latter, through the combination of protein interactions and in a manner dependent on the promoter context.