Search Results (879)

Alpha-mangostin (AM), a xanthone from Garcinia mangostana, has shown promising nephroprotective properties, but its mechanisms in acute kidney injury (AKI) remain incompletely defined. In this study, we applied an integrative network pharmacology pipeline combined with molecular docking to clarify AM’s multi-target mechanisms in AKI. We identified 128 predicted AM targets and intersected them with AKI-related genes, yielding 122 shared targets. Protein–protein interaction analysis identified ten hub genes—TNF, AKT1, IL6, SRC, CTNNB1, HSP90AA1, NFKB1, HIF1A, PPARG, and PTGS2—implicating inflammatory, hypoxia, and cell-survival pathways. KEGG enrichment highlighted HIF-1 signaling, PI3K–Akt signaling, chemokine signaling, AGE–RAGE signaling, and pathways related to cellular senescence and oxidative stress, while GO terms emphasized responses to chemical/oxygen-containing compounds, kinase activity, signal transduction, and apoptosis. Molecular docking against the ten hub proteins showed favorable binding energies across multiple targets. The strongest predicted affinities were observed for PTGS2 (−11.13 kcal/mol), TNF (−9.74 kcal/mol), and AKT1 (−9.48 kcal/mol). Docking positioned AM within the COX-2 catalytic pocket, engaging key catalytic and hydrophobic residues similar to known inhibitors. MD simulation interaction analysis confirmed that AM maintained stable contacts with key human PTGS2 residues, characterized by dominant hydrogen bonds and water-bridge interactions with SER353, TYR355, ARG513, and SER530, along with consistent hydrophobic contacts, and persistent interactions sustained throughout the 200 ns trajectory. Collectively, these results suggest that AM modulates interconnected inflammatory, hypoxic, and survival pathways relevant to AKI, acting as a multi-target ligand with notable interaction involving COX-2, TNF, and AKT1. Further experimental validation and formulation strategies to improve bioavailability are recommended for the advancement of AM toward therapeutic evaluation in AKI. Full article

Pneumonia, an acute inflammatory condition of the lung tissue, imposes a significant burden on global health and is characterized by a high rate of illness and death. The pathogenesis of the disease extends beyond infection to breakdown of redox hemostasis, where the excessive reactive oxygen species produced during the immune response inflict damage on the alveolar tissues and hence promote varying complications. This dual role of oxygen and oxidative mechanisms makes the management of pneumonia challenging, as the very oxygen that is vital for host defense, when not regulated, imposes severe lung damage. Antioxidant administration and oxygen therapy offer limited efficacy, mostly due to their non-specific action and iatrogenic harm from oxygen oversupply. These limitations are overcome by the use of emerging therapeutic strategies, which primarily focus on precision-targeted approaches. These include inhalable antioxidants, nanoparticle-based systems and biomaterials that are engineered to respond to local ROS concentrations, which aim to deliver the therapeutic agent directly to the inflamed regions of the lung. Calcium peroxide- and manganese dioxide-incorporating materials are being designed to modulate the oxygen levels, either by releasing it in hypoxic zones or scavenging it in hyperoxic microenvironments. This approach simultaneously addresses hypoxia and oxidative stress. Despite showing promising results in experimental and preclinical studies, complications related to product stability, regulatory compliance, and manufacturing scalability need to be addressed. Personalized treatment protocols, guided by biomarkers, involve the future generation of treatments, aiming to achieve a delicate recalibration of the lung’s oxidative environment for improved patient outcomes. Full article

Background: Obstructive sleep apnea (OSA) is a complex and diverse disorder affecting almost one billion individuals worldwide. Severity of untreated OSA, measured by the apnea–hypopnea index (AHI), is noted to be associated with an increased all-cause and cardiovascular mortality. Although widely used, AHI insufficiently captures disease variability as there is a poor correlation of symptoms with the AHI. There lies individual susceptibility to the effects of OSA and that parameter alone poorly predicts cardiovascular outcomes without considering intermittent hypoxia and the hemodynamic effects of OSA. Recognition of clinical, polysomnographic, and neurophysiological phenotypes offers an opportunity to refine diagnosis, prognosis, and management strategies. Methods: We conducted a narrative synthesis of the literature involving 70 articles, focusing on quantitative and qualitative (Q2) clinical traits, polysomnographic parameters, and mechanistic insights that enable subclassification of OSA beyond AHI. Evidence from large cohorts, animal models, and pathophysiological studies were reviewed. Results: Phenotyping based on a Q2 analysis of polysomnographic respiratory event predominance, event duration, positional and REM dependence, hypoxic burden, and arousal characteristics reveals significant heterogeneity in risk profiles and therapeutic response. Apnea-predominant OSA correlates with a higher oxygen desaturation index and Epworth sleepiness scale. Hypopnea-predominant OSA correlates with a cardiometabolic disease burden and may show a more favorable response to surgical therapies. The duration of respiratory events is related to cardiovascular risk, and REM-predominant OSA independently predicts hypertension and adverse cardiovascular outcomes. Supine-predominant OSA demonstrates treatment responsiveness to auto-positive airway pressure and positional therapy. Respiratory effort–related arousals (RERAs), RERA-predominant OSA and the broader respiratory disturbance index (RDI) provide neurophysiological insight often missed by AHI-based classifications. Hypoxic burden, rather than AHI, emerged as a superior predictor of cardiovascular events and mortality. Finally, arousal frequency and periodic limb movements independently predict cardiovascular morbidity. Conclusions: Employing Q2-based phenotyping that incorporates clinical, polysomnographic, and neurophysiological markers improves risk stratification, prognosis, and individualized management of OSA. Future investigations should prioritize integrating phenotypic subclassification into diagnostic criteria and treatment planning to advance precision medicine in sleep apnea care. Full article

Background: Photodynamic therapy (PDT) offers a promising complementary strategy for treating glioblastoma multiforme (GBM); however, limited control over photosensitizer activation and reduced efficacy under hypoxic conditions remain significant limitations. Methods: In this study, we present the synthesis and functional evaluation of Gal-SiX, an enzymatically activatable Si-xanthene-based activatable PDT agent designed to address these challenges. Prepared via an improved 10-step synthetic route, Gal-SiX exhibits clear turn-on fluorescence and absorbance responses upon β-galactosidase activation and efficiently generates reactive oxygen species in aqueous media. Results: Mechanistic studies revealed that Gal-SiX enables both Type I and Type II PDT pathways, a favorable feature for GBM environments characterized by restricted oxygen availability. In vitro assays conducted on U87MG glioblastoma cells and L929 healthy fibroblasts demonstrated light-dependent cytotoxicity, with IC₅₀ values of 3.30 μM and 7.19 μM, respectively. Gal-SiX also showed minimal dark toxicity (>80 μM) and potent light-induced cytotoxicity, yielding a phototoxicity index of 24.8 in glioblastoma cells. Confocal imaging and MTT assays consistently confirmed enzymatic activation and effective PDT response at the cellular level. Conclusions: Overall, this work introduces the first activatable Si-xanthene-based PDT agent for glioblastoma and provides the first evidence that the Si-xanthene scaffold can support dual Type I/II phototoxicity. These results underscore Gal-SiX’s potential as a PDT platform for addressing the unique constraints of GBM biology. Full article

Polycystic ovary syndrome (PCOS) is associated with reproductive, metabolic, and inflammatory disturbances. Alterations in T-cell subpopulations—particularly increased T helper 17 cells (Th17) and decreased regulatory T cells (Treg)—have been reported in PCOS; however, data on normoandrogenic phenotype D remain limited. Hypoxia-inducible factor 1α (HIF-1α), a key regulator of hypoxic response, also influences immune and metabolic processes and may affect the Treg/Th17 balance. To assess Treg and Th17 abundance, HIF-1α expression within these cells, and their ratios in women with phenotype D PCOS compared with healthy controls. The study included 49 women with phenotype D PCOS and 40 controls comparable in terms of age and BMI. Anthropometric, hormonal, metabolic, and inflammatory parameters were evaluated. Peripheral T-cell subsets and intracellular HIF-1α expression were analyzed by multiparameter flow cytometry. Absolute numbers of Treg and Th17 cells did not differ between groups. However, PCOS patients showed significantly higher Treg/Th17 and HIF-1α-positive Treg/HIF-1α-positive Th17 ratios. HIF-1α-positive Treg cells correlated positively with adiposity and insulin resistance markers; however, after False Discovery Rate (FDR) correction, correlations no longer remained statistically significant. Despite normoandrogenemia, PCOS patients exhibited higher hs-CRP levels. Phenotype D PCOS is characterized by altered immune cell ratios rather than absolute T-cell differences, suggesting distinct immunological features and persistent low-grade inflammation. Full article

Temozolomide and dacarbazine are untargeted anticancer prodrugs that have been widely employed in the treatment of melanoma and glioblastoma. These agents decompose into a short-lived monomethyl triazene intermediate, culminating in the release of a methyl diazonium cation that serves as the DNA-alkylating species responsible for tumour destruction. However, due to their high chemical lability, these agents have been associated with chemotherapy resistance, mutagenicity, tumour relapse, and significant off-target toxicity. One promising strategy towards the resolution of these limitations involves the design of arylmethyl triazene prodrugs, which enable targeted tumour-specific drug delivery. This review explores the various approaches used to selectively deliver alkyl aryl triazenes as alternatives to current therapies. It highlights early chemical strategies such as N-acylation and etherification of monomethyl triazenes, along with associated kinetic studies. The selective activation of novel triazenes in murine and human melanoma cells through a tyrosinase-responsive promoiety is discussed. Recent progress in nitroaromatic-based prodrugs designed to exploit the hypoxic microenvironment of glioblastoma is also examined. Additionally, we summarise the development of combi-triazenes and their underlying chemistries, which enable the simultaneous release of two active therapeutic agents. Full article

Plants are sessile organisms that use molecular oxygen to perform basic metabolic functions. However, when oxygen availability decreases to 1–5% (hypoxic stress), the plant responds transcriptionally to adjust its metabolism and survive the stress. It has been observed that during hypoxia, adenosine triphosphate (ATP) levels decrease drastically, which could trigger plant death. However, despite experiencing an energy deficit, it has been observed that during hypoxia, plants induce defense mechanisms against pathogens. Plants manage to evade pathogenic microorganisms during an energy deficit by using complex signaling networks and different levels of regulation (transcriptional, post-translational, physiological, metabolomic, etc.) that converge to respond to both types of stress (biotic and abiotic). Understanding this phenomenon would have potential applications for agriculture and crop improvement. Therefore, this review details the main mechanisms of plant response to hypoxia and how this affects immunity mechanisms, highlighting the participation of ERF-VII transcription factors as oxygen sensors and their ability to bind to the GCC-box present in promoter regions of defense genes, MAPK signaling pathways, hormonal pathways, ROS, and Ca²⁺. Full article

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by high metabolic activity, chronic endoplasmic reticulum stress, and persistent redox imbalance. Excessive immunoglobulin synthesis and adaptation to the hypoxic bone marrow microenvironment lead to sustained production of reactive oxygen species (ROS). Their excessive accumulation promotes genomic instability, disease progression, osteolytic bone disease, and resistance to therapy. Paradoxically, MM cells adapt to oxidative stress by activating antioxidant and metabolic defense mechanisms, including Nuclear factor erythroid 2-related factor 2 (NRF2)- and Heme Oxygenase 1 (HMOX1)-dependent pathways, metabolic reprogramming, and overexpression of ROS-scavenging enzymes such as peroxiredoxin 6 (PRDX6), allowing survival at the threshold of oxidative toxicity. Evidence indicates that biomarkers of oxidative stress—such as lipid and protein oxidation products, antioxidant enzyme activity, and the Oxidative Stress Score—correlate with disease stage, prognosis, and treatment response. Redox-modulating therapeutic strategies, including pharmacological ROS induction, inhibition of antioxidant defenses, and the use of natural pro-oxidant compounds, are emerging as promising adjuncts to standard MM therapies. Recent studies also highlight the gut microbiota as an indirect regulator of oxidative balance, immune modulation, and metabolic homeostasis in MM. This review summarizes current knowledge on oxidative stress in multiple myeloma, emphasizing its role in pathogenesis, drug resistance, biomarker development, and emerging therapeutic and supportive strategies. Full article

Hypoxia-dependent microRNAs play an important role in orchestrating a plant’s response to low-oxygen stress. To assess the regulatory mechanisms of the adaptive response of maize (Zea mays L.) to hypoxia, an antisense sequence was developed, and the short tandem target mimic (STTM) system was used to induce the loss of function of the mature microRNA775A (miR775a) in maize. A recombinant binary vector pBI121 cloned in E. coli cells containing the antisense sequence anti-miR775A to maize miR775A was acquired to create a line of modified A. tumefaciens EHA105. Using the puncturing method on soaked seeds, maize plants with an active anti-miR775A construct were obtained, as evidenced by a decrease of more than 10-fold in mature miR775A content and by developmental changes in the seedlings. The size of seedlings of the maize knockdown line was almost twice smaller than that of the wild-type (WT) plants. An assessment of the effects of hypoxic conditions induced by flooding of 14-day-old maize plants revealed differences in the expression and activity of several enzymes between WT and knockdown plants. The reduced miR775A levels led to a 2.1-fold drop in pyruvate levels, which resulted in decreased pyruvate kinase, pyruvate dehydrogenase, and lactate dehydrogenase activities as compared to WT plants. A decrease in miR775A content in the maize knockdown cell line also affected the function of mitochondrial and extramitochondrial isoenzymes of citrate synthase, aconitase, and fumarase under hypoxic conditions. Full article

Background: Sorafenib resistance remains a major barrier to effective therapy in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). Introduction: Here, we identified a previously undefined mechanism by which miR-21 promotes sorafenib resistance by suppressing the tumor suppressor SASH1 and enhancing HBx-driven PI3K/AKT/mTOR signaling. Methods: miR-21 expression was markedly elevated in HBV-HCC tissues, HBV-integrated HCC cell lines, and hypoxic conditions. Bioinformatic analyses and luciferase reporter assays confirmed SASH1 as a direct miR-21 target. Results: Mechanistically, SASH1 was functionally associated with HBx-related oncogenic signaling and influenced apoptotic responses. miR-21 inhibition reduced HBV-HCC cell proliferation, increased apoptosis, and restored sorafenib sensitivity in vitro. In an orthotopic HBV-HCC mouse model, the combined administration of miR-21 inhibitor and sorafenib elicited markedly greater tumor suppression and restoration of the SASH1 expression than either monotherapy did. Discussion: Therefore, these findings suggested that the miR-21/SASH1 pathway contributed to therapeutic resistance in HBV-associated HCC and highlighted that miR-21 targeting could be an efficient strategy to improve sorafenib response. Conclusions: The miR-21/SASH1 axis play a critical role in sorafenib resistance in HBV-associated HCC, and targeting miR-21 may provide a promising therapeutic strategy to enhance treatment efficacy. Full article

Background: The potent topoisomerase I inhibitor SN-38, the active metabolite of irinotecan, is limited in clinical application due to severe systemic toxicity. Prodrug strategies enabling selective activation in the tumor microenvironment offer a promising approach to improve its therapeutic index. This study aims to rationally design, synthesize, and systematically evaluate novel disulfide-based SN-38 prodrugs engineered for redox-responsive activation in hypoxic tumors. Methods: Two novel disulfide-based SN-38 prodrugs (SN-38-CSS and SN-38-LSS) were designed and synthesized; SN-38-CSS incorporates a constrained cis-piperazine-fused six-membered cyclic disulfide linker, while SN-38-LSS contains a linear disulfide tether, to differentially exploit the upregulated thioredoxin (Trx/TrxR) system in hypoxic tumor microenvironments. Results: Both prodrugs demonstrated high stability under physiological pH conditions and in human plasma, minimizing premature release. Crucially, they exhibited selective, rapid degradation in the presence of dithiol reductants (TCEP and DTT), mimicking Trx system activity, while remaining stable towards monothiols (GSH, L-Cys). In vitro cytotoxicity assays revealed that the prodrugs exhibited significantly reduced toxicity compared to SN-38 under normoxic conditions across most tested cell lines. However, under hypoxic conditions, their activity was significantly restored. Specifically, SN-38-CSS exhibited cytotoxicity comparable to SN-38 against MCF-7 and NCI-N87 cells, whereas SN-38-LSS showed lower activation efficiency. Conclusions: SN-38-CSS is identified as a promising redox and hypoxia dual-responsive prodrug candidate, highlighting the strategic use of cyclic disulfide linkers for achieving high selectivity and controlled drug release within the tumor microenvironment. Full article

Hypoxia-inducible factor (HIF) is recognized as a key transcription factor via regulating a variety of molecular responses to hypoxia, although the details are still unclear. In this study, based on bioinformatics analysis, the expression of the HIF-1α gene in T. castaneum (TcHIF-1α) under hypoxic treatments was determined. After TcHIF-1α knockdown by injecting dsRNA, larval mortality, the expression levels of oxidative stress-related genes, and enzymatic activities were measured; DNA damage was also evaluated through single cell gel electrophoresis. The result indicated that TcHIF-1α is highly conserved in structure. TcHIF-1α exhibited distinct temporal patterns, with a peak after 72 h of exposure to 2% O₂. Following TcHIF-1α knockdown, a significant increase in larval mortality (17.44 ± 5.91%) and moderate DNA damage level was found. This might be accompanied by ROS accumulation, lipid peroxidation (LPO), and suppression of antioxidant enzymatic activities. The expression of genes involved in ROS synthesis (e.g., NOX) was significantly upregulated, whereas genes responsible for mitigating oxidative stress (e.g., OGG1, XRCC1, PARP1, SOD1a) were markedly downregulated. These findings elucidate the critical role of HIF-1α in insect hypoxia adaptation by regulating the antioxidative stress, highlighting its potential as a promising target for developing novel pest control strategies. Full article

Hypoxic pulmonary hypertension (HPH), classified as Group 3 pulmonary hypertension in the current clinical classification system, represents a complex and progressive cardiopulmonary disorder characterized by elevated pulmonary arterial pressure due to chronic alveolar hypoxia. This condition significantly contributes to morbidity and mortality in patients with chronic lung diseases and individuals residing at high altitudes. The pathogenesis of HPH involves a multifactorial interplay between sustained hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, endothelial dysfunction, and inflammatory responses. This review provides a comprehensive synthesis of recent advances in HPH pathophysiology and their clinical translation, with a focus on integrating molecular mechanisms with emerging therapeutic strategies. The pathogenesis of HPH involves a complex interplay of hypoxia-inducible factor (HIF) signaling, mechanosensitive ion channel dysregulation (particularly TRPC channels), metabolic reprogramming featuring glycolytic shift and mitochondrial dysfunction, immune–inflammatory mechanisms including macrophage-centered immunopathology, and dysregulation of the nitroxidergic system. Recent clinical advances include refined risk stratification using advanced echocardiographic techniques, identification of novel biomarkers such as lactylation-associated proteins, and development of targeted therapies including immunomodulatory approaches, metabolic modulators, and epigenetic interventions. Ongoing clinical trials are investigating innovative strategies ranging from iron supplementation to nanoparticle-based drug delivery systems. Despite these advances, significant translational challenges remain, including limitations of preclinical models, patient heterogeneity, and the need for HPH-specific outcome measures. This review bridges the gap between mechanistic insights and clinical applications, offering an integrated framework that highlights precision medicine approaches, emerging therapeutic targets, and priority research directions for improving outcomes in this challenging condition. Full article

Hypoxia is a common feature of many physiological and pathological conditions, including inflammation, ischemia, and chronic lung disease, where limited oxygen availability disrupts mitochondrial metabolism and promotes excessive reactive oxygen species (ROS) generation. Hypoxia-inducible factor-1α (HIF-1α) is the central transcriptional regulator that enables cellular adaptation to low-oxygen environments by coordinating metabolic reprogramming, mitochondrial remodeling, and redox control. While HIF-1α is widely recognized for its role in promoting glycolysis, evidence indicates that it also suppresses mitochondrial ROS production through coordinated regulation of mitochondrial metabolism, biogenesis, and quality control. This review examines how HIF-1α integrates these mitochondrial and redox-adaptive mechanisms and highlights its bidirectional interactions with key stress-responsive signaling pathways, including PI3K/Akt, MAPK, Nrf2, and NF-κB, that together shape metabolic adaptation, inflammatory responses, and cell survival under hypoxic stress. By integrating these diverse mechanisms, this review provides a comprehensive understanding of the pathophysiology of hypoxia-associated diseases and underscores the therapeutic potential of targeting HIF-1α-regulated metabolic and inflammatory pathways to mitigate oxidative damage induced by hypoxia and environmental stressors. Full article

Three-dimensional (3D) spheroid cancer models provide enhanced physiological relevance relative to traditional monolayer cultures but often demonstrate restricted drug responsiveness due to their dense architecture, hypoxic gradients, and diminished therapeutic penetrance. This study overcomes these limitations by establishing a sensitized 3D spheroid cancer cell model that employs the adenovirus-mediated gene expressions of tumor-suppressor and pro-apoptotic genes consisting of MOAP-1, BAX, and RASSF1A. The optimization of adenoviral infectivity led to the discovery of an intermediate multiplicity of infection (MOI) that facilitated effective and uniform transduction while reducing cytotoxicity. Adenovirus-infected 3D spheroid cells demonstrated enhanced apoptotic activities, evidenced by increased cell death relative to untreated spheroids. When exposed to the anti-cancer compound such as piperonal and pyrazole, the sensitized spheroids exhibited significantly enhanced drug responsiveness and synergistic effects over a five-day treatment period, surpassing the effects of adenovirus or anti-cancer drug treatment alone. Notably, similar responses were noted between low- and high drug doses, suggesting an enhancement of therapeutic efficacy at lower concentrations. This sensitized 3D spheroid model constitutes a more predictive in vitro system for anti-cancer drug discovery, facilitating enhanced mechanistic evaluation and the identification of potent drug candidates with greater translational significance. Full article