Search Results (157)

Background: Insulin-degrading enzyme (IDE) has become an essential target for the clinical treatment of various important diseases, including type 2 diabetes, Alzheimer’s disease, and breast cancer, owing to its diverse substrate specificity. Particularly in cancer therapy, IDE inhibitors have received significant attention. Methods: We evaluated the in vitro inhibitory activity (IC₅₀) of ethyl 2-(3,5-dioxo-2-p-tolyl-1,2,4-thiadiazolidin-4-yl) acetate (1) against wild-type IDE. The mechanism of action was investigated using Lineweaver–Burk double reciprocal plots and molecular docking analyses. Additionally, we examined the structure–activity relationship, cytotoxicity, selectivity, and effects on cell migration to assess its potential druggability. Based on molecular docking results, we prepared the mutant protein T142A and compared its inhibitory effects with those of the wild-type and mutant proteins. Results: Compound 1 exhibited an inhibitory effect on IDE (IC₅₀ = 3.60 μM). This compound exerts its inhibitory effect through competitive binding to the catalytic site of IDE. Compound 1 demonstrated selective cytotoxicity toward cancer cells compared to normal cells, effectively inhibiting IDE at concentrations ≤ 10 μM. At a concentration of 3.6 μM, the inhibitory effect of the compound on cancer cell migration was significantly stronger than that observed in normal cells. Although the T142A mutant retained catalytic hydrolysis activity with a similar K_m value, its reaction rate was markedly lower than that of the wild-type enzyme. Conclusions: Compound 1 exhibits a competitive inhibitory effect on IDE, selectively targeting IDE with greater toxicity toward cancer cells compared to normal cells. It also inhibits cancer cell migration. Notably, 1 demonstrates significantly stronger inhibitory activity against the T142A mutant than the wild-type IDE, indicating that the Thr142 residue plays a crucial role in the interaction between the IDE hydrophobic pocket and 1. These findings suggest that 1 holds potential as a chemotherapeutic agent for treating IDE-related cancers, including breast, prostate, and pancreatic cancers. Full article

Bacteria and phages have coexisted for billions of years engaging in continuous evolutionary arms races that drive reciprocal adaptations and resistance mechanisms. Among the diverse antiviral strategies developed by bacteria, modification or masking phage receptors as well as their physical removal via extracellular vesicles are the first line of defense. These vesicles play a pivotal role in bacterial survival by mitigating the effects of various environmental threats, including predation by bacteriophages. The secretion of extracellular vesicles represents a highly conserved evolutionary trait observed across all domains of life. Bacterial extracellular vesicles (BEVs) are generated by a wide variety of Gram (+), Gram (−), and atypical bacteria, occurring under both natural and stress conditions, including phage infection. This review addresses the multifaceted role of BEVs in modulating bacteria–phage interactions, considering the interplay from both bacterial and phage perspectives. We focus on the dual function of BEVs as both defensive agents that inhibit phage infection and as potential facilitators that may inadvertently enhance bacterial susceptibility to phages. Furthermore, we discuss how bacteriophages can influence BEV production, affecting both the quantity and molecular composition of vesicles. Finally, we provide an overview of the ecological relevance and efficacy of BEV–phage interplay across diverse environments and microbial ecosystems. Full article

Background: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of immature T cells, driven by dysregulated transcriptional networks and oncogenic signaling pathways. Here, we present the first comprehensive analysis of the expression and regulation of TSPAN32, a tetraspanin implicated in lymphocyte homeostasis, in T-ALL. Methods: Transcriptomic data from the Leukemia MILE study (GSE13159) were analyzed to assess TSPAN32 expression across leukemic subtypes. Gene Set Enrichment Analysis (GSEA) was performed to explore biological pathways associated with TSPAN32-correlated genes. For mechanistic validation, HPB-ALL cells were used as a model, with NOTCH signaling inhibited by γ-secretase inhibitor (GSI) treatment and TAL1–LMO1 overexpression induced through doxycycline-inducible lentiviral vectors. Gene expression changes were quantified by RT-qPCR. Results: TSPAN32 was frequently downregulated in T-ALL compared to healthy bone marrow, although expression was retained in a subset of cases. GSEA revealed that TSPAN32-correlated genes were inversely associated with cell cycle–related programs, consistent with its established role as a negative regulator of T cell proliferation. Mechanistically, TAL1–LMO1 overexpression strongly induced TSPAN32, while GSI-mediated NOTCH inhibition partially reactivated its expression. Interestingly, GSI treatment also increased TAL1 levels despite downregulating LMO1. Conversely, TAL1–LMO1 overexpression suppressed NOTCH1 and NOTCH3, highlighting a reciprocal regulatory interplay between NOTCH and TAL1/LMO1 oncogenic circuits that shapes TSPAN32 expression dynamics in T-ALL. Conclusions: This study identifies TSPAN32 as a novel transcriptional target under the influence of key leukemogenic pathways and suggests its potential role as a modulator of leukemic T cell proliferation, with implications for therapeutic strategies targeting TAL1 and NOTCH signaling. Full article

Polymicrobial biofilms involving fungal and bacterial species are increasingly recognized as contributors to persistent infections, particularly in the oral cavity. Candida albicans and Aggregatibacter actinomycetemcomitans are two commensals that can turn into opportunistic pathogens and are able to form robust biofilms. Objectives: This study aimed to assess the interaction dynamics between these two microorganisms and to evaluate their susceptibility to fluconazole and azithromycin in single- and mixed-species forms. Methods: Biofilm biomass was quantified using crystal violet assays, while biofilm cell viability was assessed through CFU enumeration (biofilm viability assay). To assess the resistance properties of single versus mixed-species coincubations, we applied the antimicrobial susceptibility test (AST) to each drug, and analysed spatial organization with confocal laser scanning microscopy, using PNA-FISH. Results: The results indicated that both species can coexist without significant mutual inhibition. However, a non-reciprocal synergism was also observed, whereby mixed-species biofilm conditions promoted the growth of A. actinomycetemcomitans, while C. albicans growth remained stable. As expected, antimicrobial tolerance was elevated in mixed cultures, likely due to enhanced extracellular matrix production and potential quorum-sensing interactions, contributing to increased resistance against azithromycin and fluconazole. Conclusions: This study provides novel insights into previously rarely explored interactions between C. albicans and A. actinomycetemcomitans. These findings underscore the importance of investigating interspecies interactions within polymicrobial biofilms, as understanding their mechanisms, such as quorum-sensing molecules and metabolic cooperation, can contribute to improved diagnostics and more effective targeted therapeutic strategies against polymicrobial infections. Full article

Guvermectin, a Streptomyces-derived purine nucleoside compound, exhibits dual bioactivities as a plant growth regulator and an antibacterial agent. While its biosynthetic gene cluster (BGC) is regulated by the cluster-situated activator GvmR and the adjacent repressor GvmR2, the role of distal transcriptional regulators (TRs) in guvermectin biosynthesis remains unexplored. Here, we identified ScnR1, a highly conserved LacI-family TR located far from the guvermectin BGC, which is directly activated by GvmR. Overexpression of scnR1 significantly suppressed guvermectin biosynthesis. Further investigations revealed that ScnR1 competitively binds to the gvmR, gvmA, and O1 promoters (overlapping with the GvmR-binding sites), thereby inhibiting the guvermectin BGC transcription. Moreover, ScnR1 formed a reciprocal feedback loop with the adjacent repressor GvmR2, where each repressor inhibits the other’s expression. These findings reveal a multi-layered regulatory mechanism wherein LacI-family TRs fine-tune guvermectin biosynthesis through competitive DNA binding and reciprocal feedback control. This study offers new perspectives on the hierarchical control of secondary metabolism in Streptomyces and provides valuable theoretical guidance for the engineering of strains with enhanced natural product production. Full article

Magnetic shape memory alloys have attracted considerable attention due to their multifunctional properties. Among these materials, Ni-Mn-Ga alloys are distinguished by their ability to achieve up to 10% strain when exposed to a magnetic field, a characteristic predominantly observed in single-crystal samples. Consequently, it is essential to develop nanomaterials with a crystal structure closely resembling that of a single crystal. In this study, an epitaxial Ni-Mn-Ga thin film was fabricated using Pulsed Laser Deposition on an Al₂O₃ $\left(11\overline{2}0\right)$ single-crystal substrate. The crystal structure was characterised through X-ray diffraction methodologies, such as symmetrical $2\theta -\omega$ scans, pole figures, and reciprocal space maps. The results indicated that the sample was mainly in a slightly distorted cubic austenite phase, and some incipient martensite phase also appeared. A detailed microstructural analysis, performed by transmission electron microscopy, confirmed that certain regions of the sample exhibited an incipient transformation to the martensite phase. Regions closer to the substrate retained the austenite phase, suggesting that the constraint imposed by the substrate inhibits the phase transition. These results indicate that it is possible to grow high crystalline quality thin films of Ni-Mn-Ga by Pulsed Laser Deposition. Full article

The bone marrow microenvironment is a dynamic and complex niche that plays a central role in the development, progression, and therapeutic resistance of leukemia. Among the various stromal and immune cells that compose this microenvironment, adipocytes are increasingly recognized as active participants rather than passive bystanders. These cells contribute to leukemia pathophysiology by supplying leukemic cells with vital metabolic fuels such as free fatty acids and glutamine, which support cellular bioenergetics and biosynthesis. Furthermore, adipocytes secrete adipokines—including leptin, adiponectin, and others—that influence leukemic cell proliferation, apoptosis, and chemoresistance. Leukemic cells, in turn, are not merely recipients of these signals, but actively remodel the marrow niche to their advantage. They can suppress adipogenesis, inhibit the differentiation of mesenchymal stem cells into adipocytes, or reprogram existing adipocytes to adopt a tumor-supportive phenotype. These transformed adipocytes may enhance leukemic cell survival, dampen immune responses, and create a metabolic sanctuary that enables resistance to standard chemotherapies. This reciprocal and dynamic interaction between leukemic cells and adipocytes contributes significantly to minimal residual disease and relapse, posing a major challenge for durable remission. Recent advances in tissue engineering—such as organ-on-chip and 3D co-culture systems—offer promising platforms to recapitulate and study these leukemia–adipocyte interactions with high fidelity. These models facilitate mechanistic insights and provide a foundation for developing novel therapeutic strategies aimed at disrupting the metabolic and paracrine crosstalk within the leukemic niche. Targeting the adipocyte–leukemia axis represents a compelling and underexplored avenue for improving leukemia treatment by sensitizing malignant cells to existing therapies and overcoming the protective influence of the bone marrow microenvironment. Full article

Background: In addition to its known antioxidant function, the reduced form of vitamin C, ascorbate, also acts as a neuromodulator in the nervous system. Previous work showed a reciprocal interaction of ascorbate with glutamate in chicken embryo retinal cultures. Ascorbate modulates extracellular glutamate levels by inhibiting excitatory amino acid transporter 3 and promoting the activation of NMDA receptors and the consequent activation of intracellular signaling pathways involved in transcription and survival. Objective: In the present work, we investigated the regulation of AKT phosphorylation by ascorbate in chicken embryo retina cultures. Methodology: Cultures of chicken embryo retina cells were tested using Western blot, immunocytochemistry, fluorescent probe transfection, and cellular imaging techniques. Results: Our results show that ascorbate induces a concentration and time-dependent increase in AKT phosphorylation via the accumulation of extracellular glutamate, the activation of glutamate receptors, and the activation of the PI3K pathway. Ascorbate produces an increase in intracellular calcium accumulation and, accordingly, AKT phosphorylation by ascorbate is blocked by the calcium chelator BAPTA-AM. Moreover, AKT phosphorylation is also blocked by the nitric oxide synthase inhibitor 7-nitroindazole, indicating that it is mediated by calcium and nitric oxide-dependent mechanisms. Conclusions: We demonstrate that ascorbate modulates the PI3K/AKT pathway in retinal cultures through the activation of glutamate receptors and NO production in a calcium-dependent manner. Given that previous research has shown that glutamate induces ascorbate release in retinal cultures, our findings emphasize the significance of the reciprocal interactions between ascorbate and glutamate in retinal development. These findings provide further evidence supporting the role of ascorbate as a neuromodulator in retinal development. Full article

Background/Objectives: Sepsis has been shown to depress arterial baroreceptor function, and this effect is counterbalanced by the cholinergic anti-inflammatory pathway. Considering the importance of central adenosine receptors in baroreceptor function, this study tested whether central adenosine A3 receptors (A3ARs) modulate the cholinergic-baroreflex interaction in sepsis and whether this interaction is modulated by mitogen-activated protein kinases (MAPKs) and related proinflammatory cytokines. Methods: Sepsis was induced by cecal ligation and puncture (CLP) and rats were instrumented with femoral and intracisternal (i.c.) catheters. Baroreflex sensitivity (BRS) was measured 24 h later in conscious animals using the vasoactive method, which correlates changes in blood pressure caused by i.v. phenylephrine (PE) and sodium nitroprusside (SNP) to concomitant reciprocal changes in heart rate. Results: The reduction in reflex bradycardic (BRS-PE), but not tachycardic (BRS-SNP), responses elicited by CLP was reversed by i.v. nicotine in a dose-related manner. The BRS-PE effect of nicotine was blunted following intracisternal administration of IB-MECA (A3AR agonist, 4 µg/rat). The depressant action of IB-MECA on the BRS facilitatory action of nicotine was abrogated following central inhibition of MAPK-JNK (SP 600125), PI3K (wortmannin), and TNFα (infliximab), but not MAPK-ERK (PD 98059). Additionally, the nicotine suppression of sepsis-induced upregulation of NFκB and NOX2 expression in the nucleus tractus solitarius (NTS) was negated by A3AR activation. The molecular effect of IB-MECA on NFκB expression disappeared in the presence of SP 600125, wortmannin, or infliximab. Conclusions: The central PI3K/MAPK-JNK/TNFα pathway contributes to the restraining action of A3ARs on cholinergic amelioration of sepsis-induced central neuroinflammatory responses and impairment of the baroreceptor-mediated negative chronotropism. Full article

Reciprocating liquid hydrogen pumps are essential equipment for hydrogen refueling stations with liquid hydrogen stored. The valves play a crucial role in facilitating unidirectional flow and the pressurization of liquid hydrogen within the pump. This paper establishes a comprehensive numerical model to simulate the whole working cycle of a reciprocating liquid hydrogen pump. The influence of valve parameters and pump operating conditions on the motion characteristics of valves, including lift, closing lag angle, and impact velocity, is investigated. The results indicate that with the maximum lift of the suction valve at 10 mm and the discharge valve at 5 mm, the closing lag angle is minimal, and the impact velocity of the valve falls within an acceptable range. The optimal rotation speed range is between 200 and 300 rpm, within which both the closing lag angle and impact velocity of valves are minimized. Excessive maximum lift and low rotational speed lead to significant oscillations and high impact velocity in valve movement with the effects being more pronounced in the suction valve. The effects of the subcooling degree of inflow liquid hydrogen on the valve motion are further analyzed. The findings suggest that the subcooling degree of inflow liquid hydrogen helps inhibit the vaporization in the pump operation and ensures the valves work correctly. This work would contribute to pump optimization and valve collision failure analysis in reciprocating liquid hydrogen pumps. Full article

Background: Reciprocal inhibition (RI) is a spinal reflex that controls posture and movement. The modulation of spinal RI represented by the H-reflex has been studied, before and after voluntary contraction and electrical nerve stimulation but not during voluntary, electrically induced muscle contraction or a combination of voluntary and electrically induced muscle contractions. This study investigates the effects of the ongoing voluntary isometric contraction, the electrically induced isometric contraction, and the combination of voluntary with electrically induced isometric contraction of the Tibialis Anterior (TA) muscle on spinal RI represented by Soleus H-reflex. Methods: Eighteen healthy adults participated. Soleus H-reflex and M-response were measured during four different conditions as follows: (1) at rest, (2) electrically induced isometric contraction of the TA, (3) voluntary isometric contraction of the TA with a 1 kg force, and (4) combined voluntary and electrically induced isometric contraction of the TA with a 1 kg force. Results: The ANOVA clearly demonstrated significant differences in Soleus H-reflex amplitude across the four recording conditions (F3,16, 17.28, p < 0.001). The amplitude at rest was significantly higher than during electrically induced isometric contraction, voluntary isometric contraction, and the combined contraction conditions (p < 0.05). Furthermore, the amplitude recorded during the electrically induced isometric contraction condition significantly surpassed that of voluntary isometric contraction and the combined contraction conditions (p < 0.05). Moreover, there was no significant difference between Soleus H-reflex amplitude recorded during voluntary isometric contraction and the combined voluntary isometric contraction and electrically induced isometric contraction (p < 0.87). The combined voluntary isometric contraction and electrically induced isometric contraction condition had a higher inhibitory effect on the Soleus H-reflex with no significant differences from voluntary isometric contraction. Moreover, both were significantly better than electrically induced isometric contraction (p = 0.05). In terms of Soleus H-reflex latency, there was no significant difference among all four conditions (p > 0.05), meaning Soleus H-reflex latency was not influenced by the conditions. Conclusions: RI can be best modulated by combining voluntary with electrically induced isometric muscle contractions. Full article

Pancreatic cancer is an aggressive tumor with dismal prognosis. Neural invasion is one of the pathological hallmarks of pancreatic cancer. Peripheral nerves can modulate the phenotype and behavior of the malignant cells, as well as of different components of the tumor microenvironment, and thus affect tumor growth and metastasis. From a clinical point of view, neural invasion is translated into intractable pain and represents a predictor of tumor recurrence and poor prognosis. Several molecules are implicated in neural invasion and pain onset in PDAC, including neutrophins (e.g., NGF), chemokines, adhesion factors, axon-guidance molecules, different proteins, and neurotransmitters. In this review, we discuss the role of nerves within the pancreatic cancer microenvironment, highlighting how infiltrating nerve fibers promote tumor progression and metastasis, while tumor cells, in turn, drive nerve outgrowth in a reciprocal interaction that fuels tumor advancement. We outline key molecules involved in neural invasion in pancreatic cancer and, finally, explore potential therapeutic strategies to target neural invasion, aiming to both inhibit cancer progression and alleviate cancer-associated pain. Full article

Soluble epoxide hydrolase (sEH) is a bifunctional enzyme with epoxide hydrolase activity in the C-terminal domain (C-EH) and lipid phosphate phosphatase activity in the N-terminal domain (N-phos). The C-EH hydrolyzes bioactive epoxy fatty acids such as epoxyeicosatrienoic acid (EET). The N-phos hydrolyzes lipid phosphomonesters, including the signaling molecules of lysophosphatidic acid (LPA). Here, we report that the C-EH and N-phos are reciprocally regulated by their respective substrates. Full-length sEH (sEH-FL) showed positive cooperativity toward the substrate for each domain. Similar cooperativity was found when truncated enzymes having only C- and N-terminal domains, sEH-C and sEH-N, respectively, were used, suggesting an intra-domain nature of the cooperativity. In addition, the N-phos substrate LPA inhibited C-EH activity in sEH-FL and sEH-C equally. Similarly, the C-EH substrate EET inhibited N-phos activity. Structural and kinetic data suggest the presence of allosteric sites in each domain of the sEH enzyme, which share the binding of LPA and EET. Thus, each of the two sEH activities is regulated by a substrate of its own and by that of the other domain. This mechanism may explain why sEH has evolved to have two different enzyme activities, which possibly allows sEH to balance the metabolism of bioactive lipids. Full article

Reciprocal inhibition is often diminished in elderly individuals and those with upper motor neuron disorders. This reduction in reciprocal inhibition can hinder smooth joint movement. For subjects who have increased muscle tone and a limited range of motion in the joints, we focused on visual kinesthetic illusions as an intervention to increase reciprocal inhibition. We aimed to investigate the effects of visual kinesthetic illusions on reciprocal inhibition and motor function in the ankle joint. Participants participated in two experiments measuring reciprocal inhibition, namely reciprocal Ia inhibition and D1 inhibition, as well as motor functions related to ankle dorsiflexion and plantar flexion. Visual kinesthetic illusion was induced by displaying an image of each subject’s foot on a monitor. Our results showed that the visual kinesthetic illusion enhanced D1 inhibition and improved motor function in the ankle joint by prioritizing agonist muscle activity. We also observed a correlation between reciprocal inhibition and the muscle activity ratio. These findings suggest that visual kinesthetic illusions may improve motor function by increasing reciprocal inhibition. This study is the first to demonstrate the effects of visual kinesthetic illusion on reciprocal inhibition, and we believe that these findings can be applied in rehabilitation. Full article

Extensive and profound landscape alterations significantly contribute to ecological vulnerability in environmentally delicate regions. Existing research primarily emphasizes ecological risks caused by landscape alterations, while overlooking vulnerable characteristics of landscape functions; particularly lacking are studies on the driving mechanism of landscape ecological risk through the reciprocal relationship between landscape pattern risk and function risk. Based on these issues, this paper constructed a landscape pattern risk index (LPRI), a landscape function risk index (LFRI), and a landscape ecological risk index (LERI) in the counties of the dry–hot valley of the Jinsha River in southwest China. By employing a coupling degree and a coordination model, we analyzed temporal and spatial variations in the interaction between two types of ecological risk, thereby revealing the driving mechanisms of landscape ecological risk. The results indicated that the average LPRI values of the study area were 0.373, 0.327, and 0.427, respectively, while the average LFRI values were 0.451, 0.356, and 0.442 in 2000, 2010, and 2020, respectively. More than 90% of the study area exhibited a medium coupling relationship between the two types of ecological risks. The area proportion of the coupling coordination regions has increased from 25.58% to 31.07% from 2010 to 2020. The two types of risk exhibited a low level of constraint inhibition. Extremely evident expansion of high pattern–function risk areas and the area increase of coupling coordination region resulted in the acceleration of regional landscape ecological risk level. Increasing competition between market-driven land-use activities and ecological regulations from the government has rendered the diversification of landscape ecological risk sources and its underlying mechanisms intricate. This study serves as a model reference for assessing landscape ecological risk and a theoretical basis for sustainable landscape management and ecological regulation in the Yangtze River basin. Full article