Partial Inhibition Research Articles

A fast-acting inhibitor of blood-stage P. falciparum with mechanism distinct from artemisinin and chloroquine.

Artemisinins are first-line treatment for malaria, prized for their extremely fast reduction of parasite load in patients. New fast-acting antimalarial compounds are urgently needed to counter artemisinin resistance, but the fast parasite reduction observed with artemisinins is rare among antimalarial compounds. Here we show that MMV1580853 has a very fast in vitro killing rate, comparable to that of dihydroartemisinin. Near-complete parasite growth inhibition was observed within 1 hour of treatment with MMV1580853 and dihydroartemisinin, while chloroquine, another fast-acting antimalarial, showed partial growth inhibition after 1h. MMV1580853 was reported to inhibit prenyltransferases, but its fast killing rate is inconsistent with this mechanism-of-action and we were unable to validate any of 3 annotated P. falciparum prenyltransferases as MMV1580853 targets. MMV1580853 also did not phenocopy the inhibition phenotype of either chloroquine or dihydroartemisinin. These results indicate that MMV1580853 has a distinct mechanism-of-action leading to a very fast killing rate. MMV1580853 compound development and investigation of its mechanism-of-action will be critical avenues in the search for drugs matching the remarkable clinical efficacy of artemisinin.

Effects of vitamin D status on cutaneous wound healing through modulation of EMT and ECM

To investigate the effects of vitamin D status on cutaneous wound healing, C57BL/6J mice were fed diets with different vitamin D levels or injected intraperitoneally with 1α,25(OH)2D3. Dorsal skin wounds were created and wound edge tissues were collected on days 4, 7, 11, and 14 postwounding. The proliferation and migration of HaCaT cells treated with shVDR or 1α,25(OH)2D3 were assessed. Vitamin D deficiency (VDD) decreased wound closure and might delay inflammatory response, shown by slower inflammatory cell infiltration, decreased IL6 and TNF expression in early phase followed by an increase later. VDD might postpone epithelial-mesenchymal transition (EMT), initially characterized by higher epithelial markers and lower mesenchymal markers, followed by opposite appearance later. Dietary vitamin D supplementation and 1α,25(OH)2D3 intervention tended to accelerate EMT. Regarding extracellular matrix (ECM), VDD appeared to reduce collagen deposition on day 4 and downregulated fibronectin, COL3A1, and MMP9 expression early, followed by an increase later, together with an initial increase and subsequent decrease in Timp1 mRNA expression. Dietary vitamin D intervention promoted fibronectin and MMP9 expression on day 4 and then downregulated their expression on day 14. TGFb1/SMAD2/3 signaling seemed to be downregulated by VDD and upregulated by 1α,25(OH)2D3. In vitro, partial inhibition of VDR by shVDR tended to inhibit HaCaT cell proliferation and migration, EMT, and TGFb1/SMAD2/3 signaling, whereas 1α,25(OH)2D3 appeared to generate opposite effects. In conclusion, VDD hindered cutaneous wound healing, potentially due to impaired inflammatory response, delayed EMT, decreased ECM, and inhibited TGFb1/SMAD2/3 pathway. Vitamin D and 1α,25(OH)2D3 tended to enhance EMT and ECM.

Studies on in vivo antithrombotic activity of quercetin, a natural flavonoid isolated from a traditional medicinal plant, African eggplant (Solanum indicum)

Ethnopharmacological relevanceEvery year, cardiovascular diseases (CVDs) account for about 17.9 million deaths, making them the primary cause of both morbidity and mortality. Conventional drugs, which are often prescribed to treat cardiovascular diseases, are costly and have adverse effects. Consequently, dietary modifications and other medications are needed. Traditional use of Solanum indicum as cardiotonic to treat hypertension and anticoagulant potency has been reported but poorly evaluated scientifically. Aim of the studyThis study investigated the in vivo anticoagulant activity and mechanism of anticoagulation of quercetin (QC), a bioactive compound isolated from S. indicum (SI) hydroethanolic fruit extract. Materials and methodsBioassay-guided fractionation (anticoagulant activity) extracted QC from hydroethanolic SI extract. QC was extensively characterized biochemically and pharmacologically. The interaction between QC and thrombin was investigated using spectrofluorometric and isothermal calorimetric methods. Cytotoxicity, antiplatelet, and thrombolytic studies were carried out in vitro. The Swiss albino mice were used to assess the in vivo, anticoagulant, and antithrombotic activities of QC. ResultsQC exhibits anticoagulant activity via (i) uncompetitive inhibition of thrombin but not FXa with a Ki value of 33.11 ± 4.2 μM and (ii) a partial inhibition of thrombin-catalyzed platelet aggregation with an IC50 value of 13.2 ± 1.2 μM. The experimental validation of the in silico study's prediction of QC's binding to thrombin was confirmed by spectrofluorometric and isothermal calorimetric analyses. QC was nontoxic to mammalian, non-hemolytic cells and demonstrated thrombolytic activity by activating plasminogen. QC demonstrated in vivo anticoagulant efficacy, preventing k-carrageen-induced thrombus formation in mice's tails. In the acute circulatory stasis paradigm in mice, QC reduces thromboxane B2 (TXB2) and endothelin-1 (ET-1) while increasing nitric oxide synthase (eNOS) and 6-keto prostaglandin F1α (6-keto-PGF1 α). ConclusionEffective in vivo anticoagulant and antithrombotic properties of S. indicum's bioactive component QC point to the plant's potential use as a herbal anticoagulant medication for preventing and treating cardiovascular diseases linked to thrombosis.

Environmental Hot Spots and Resistance-Associated Application Practices for Azole-Resistant Aspergillus fumigatus, Denmark, 2020-2023.

Azole-resistant Aspergillus fumigatus (ARAf) fungi have been found inconsistently in the environment in Denmark since 2010. During 2018-2020, nationwide surveillance of clinical A. fumigatus fungi reported environmental TR34/L98H or TR46/Y121F/T289A resistance mutations in 3.6% of isolates, prompting environmental sampling for ARAf and azole fungicides and investigation for selection of ARAf in field and microcosmos experiments. ARAf was ubiquitous (20% of 366 samples; 16% TR34/L98H- and 4% TR46/Y121F/T289A-related mechanisms), constituting 4.2% of 4,538 A. fumigatus isolates. The highest proportions were in flower- and compost-related samples but were not correlated with azole-fungicide application concentrations. Genotyping showed clustering of tandem repeat-related ARAf and overlaps with clinical isolates in Denmark. A. fumigatus fungi grew poorly in the field experiment with no postapplication change in ARAf proportions. However, in microcosmos experiments, a sustained complete (tebuconazole) or partial (prothioconazole) inhibition against wild-type A. fumigatus but not ARAf indicated that, under some conditions, azole fungicides may favor growth of ARAf in soil.

Pharmacokinetics, pharmacodynamics, and safety of asundexian in healthy Chinese and Japanese volunteers, and comparison with Caucasian data.

There is an unmet clinical need for effective anticoagulant therapies for the management of thromboembolic diseases that are not associated with a relevant risk of bleeding. Asundexian (BAY 2433334) is an oral, direct, small-molecule inhibitor of activated factor XI (FXIa). Phase I data from healthy Caucasian male participants indicated predictable pharmacokinetic (PK) and pharmacodynamic (PD) profiles and no clinically relevant bleeding-related adverse events (AEs). Reported here are data from two phase I, randomized, placebo-controlled, single- and multiple-dose escalation studies of asundexian conducted in 60 healthy men: 24 Japanese and 36 Chinese. Baseline characteristics were comparable between the treatment groups. All treatment-emergent AEs were mild, with no serious AEs or AEs of special interest reported. Systemic exposure to asundexian increased dose proportionally after single or multiple dosing, with relatively low accumulation following multiple once-daily dosing in both Chinese and Japanese volunteers. Asundexian induced dose-dependent prolongation of activated partial thromboplastin time and inhibition of FXIa activity, with no effects on prothrombin time or FXI concentration in Japanese participants. There were no clinically relevant interethnic differences in PK profile across the Japanese, Chinese, and Caucasian (data from the previous phase I study) participants and no clinically relevant difference in PD response between Japanese and Caucasian participants.

MTORC1 activity oscillates throughout the cell cycle, promoting mitotic entry and differentially influencing autophagy induction

Mechanistic Target of Rapamycin Complex 1 (mTORC1) is a master metabolic regulator that is active in nearly all proliferating eukaryotic cells; however, it is unclear whether mTORC1 activity changes throughout the cell cycle. We find that mTORC1 activity oscillates from lowest in mitosis/G1 to highest in S/G2. The interphase oscillation is mediated through the TSC complex but is independent of major known regulatory inputs, including Akt and Mek/Erk signaling. By contrast, suppression of mTORC1 activity in mitosis does not require the TSC complex. mTORC1 has long been known to promote progression through G1. We find that mTORC1 also promotes progression through S and G2 and is important for satisfying the Chk1/Wee1-dependent G2/M checkpoint to allow entry into mitosis. We also find that low mTORC1 activity in G1 sensitizes cells to autophagy induction in response to partial mTORC1 inhibition or reduced nutrient levels. Together, these findings demonstrate that mTORC1 is differentially regulated throughout the cell cycle, with important phase-specific consequences for proliferating cells.

Interactive effects of soil salinity and nitrogen fertilizer types on nitrous oxide and ammonia fluxes

Soil salinization, impaired by climate change and poor management practices, poses a global threat, particularly in arid and semi-arid regions, leading to significant land degradation. This study aims to investigate the effects of different nitrogen (N) fertilizer sources (urea, ammonium-sulfate, and biogas waste) on CO2, N2O, and NH3 emissions and soil enzyme activities in two soil types varying in salinity level (non-saline: EC = 1.15 dS m−1, and saline: EC = 35.80 dS m−1) in a robotized continuous-flow soil incubation system. Our results showed a sharp increase in N2O and CO2 emissions (up to 0.51 ± 0.02 g N2O-N ha−1 day−1, 28.1 ± 3.9 kg CO2-C ha−1 day−1) in non-saline soils following soil rewetting, attributed to bacterial denitrification. However, this pattern was not observed in saline soils, suggesting that salinity causes partial inhibition to the regeneration of soil organic matter mineralization and denitrification processes after rewetting. Although salinity did not alter the overall cumulative N2O losses in any fertilizer treatment, it significantly delayed the evolution of N2O peak during the incubation period. On the other hand, NH3 volatilization was significantly higher in N-fertilized saline soils compared to non-saline soils (241% and 157% in ammonium-sulfate and biogas waste treatments, respectively), except for urea treatment, likely due to the decrease in nitrification rates. Furthermore, the study clearly showed lower soil enzyme activity levels for both nitrate reductase and urease activity. Interestingly, the lowest NH3 emissions were measured in urea treatment in both soils. Overall, our findings highlight the complex interplay between soil salinity, nitrogen fertilizer sources, and microbial processes, significantly influencing gaseous nitrogen emissions and N cycling in agricultural soils. Identifying the specific fertilizer treatments that minimize or maximize gaseous nitrogen losses in varying soil salinity, may guide the selection of appropriate fertilization strategies for farmers and policymakers to mitigate environmental impacts of fertilizer use during agricultural production.

A CDK1 phosphorylation site on Drosophila PAR-3 regulates neuroblast polarisation and sensory organ formation.

The generation of distinct cell fates during development depends on asymmetric cell division of progenitor cells. In the central and peripheral nervous system of Drosophila, progenitor cells respectively called neuroblasts or sensory organ precursors use PAR polarity during mitosis to control cell fate determination in their daughter cells. How polarity and the cell cycle are coupled, and how the cell cycle machinery regulates PAR protein function and cell fate determination is poorly understood. Here, we generate an analog sensitive allele of CDK1 and reveal that its partial inhibition weakens but does not abolish apical polarity in embryonic and larval neuroblasts and leads to defects in polarisation of fate determinants. We describe a novel in vivo phosphorylation of Bazooka, the Drosophila homolog of PAR-3, on Serine180, a consensus CDK phosphorylation site. In some tissular contexts, phosphorylation of Serine180 occurs in asymmetrically dividing cells but not in their symmetrically dividing neighbours. In neuroblasts, Serine180 phosphomutants disrupt the timing of basal polarisation. Serine180 phosphomutants also affect the specification and binary cell fate determination of sensory organ precursors as well as Baz localisation during their asymmetric cell divisions. Finally, we show that CDK1 phosphorylates Serine-S180 and an equivalent Serine on human PAR-3 in vitro.

Chemical and physical effects of the addition of thermochromic VO2 particles to cement

This work aims to deepen the knowledge of systems formed by cement and thermochromic vanadium dioxide particles. Cement paste specimens with 9 % addition of monoclinic VO2 particles show a significant delay of the hydration at early ages with respect to plain cement specimens, seemingly due to the partial inhibition of hydrates precipitation during the first 24 h of reaction. Upon further hydration, a re-activation of the hydration reactions gives rise to a higher mechanical strength and a more refined pore structure in the paste with VO2 addition at 28 days, attributed to the enhanced formation of C–S–H. The stability of the VO2 particles within the matrix is confirmed along the hydration process and provides the cement paste with the associated thermochromic behavior that is demonstrated by a change in the reflection in the near infrared wavelength range upon cooling from 70 °C. The results confirm the viability of producing VO2-based thermochromic cementitious materials for building envelopes. The next steps in their development should target the enhancement of the solar reflectance modulation in order to produce a significant impact in the energy efficiency of buildings and the urban overheating effect.

Oncofetal SNRPE promotes HCC tumorigenesis by regulating the FGFR4 expression through alternative splicing.

Due to insufficient knowledge about key molecular events, Hepatocellular carcinoma (HCC) lacks effective treatment targets. Spliceosome-related genes were significantly altered in HCC. Oncofetal proteins are ideal tumor therapeutic targets. Screening of differentially expressed Spliceosome-related oncofetal protein in embryonic liver development and HCC helps discover effective therapeutic targets for HCC. Differentially expressed spliceosome genes were analysis in fetal liver and HCC through bioinformatics analysis. Small nuclear ribonucleoprotein polypeptide E (SNRPE) expression was detected in fetal liver, adult liver and HCC tissues. The role of SNRPE in HCC was performed multiple assays in vitro and in vivo. SNRPE-regulated alternative splicing was recognized by RNA-Seq and confirmed by multiple assays. We herein identified SNRPE as a crucial oncofetal splicing factor, significantly associated with the adverse prognosis of HCC. SOX2 was identified as the activator for SNRPE reactivation. Efficient knockdown of SNRPE resulted in the complete cessation of HCC tumorigenesis and progression. Mechanistically, SNRPE knockdown reduced FGFR4 mRNA expression by triggering nonsense-mediated RNA decay. A partial inhibition of SNRPE-induced malignant progression of HCC cells was observed upon FGFR4 knockdown. Our findings highlight SNRPE as a novel oncofetal splicing factor and shed light on the intricate relationship between oncofetal splicing factors, splicing events, and carcinogenesis. Consequently, SNRPE emerges as a potential therapeutic target for HCC treatment. Model of oncofetal SNRPE promotes HCC tumorigenesis by regulating the AS of FGFR4 pre-mRNA.

Subcutaneous administration of a novel TRPM8 antagonist reverses cold hypersensitivity while attenuating the drop in core body temperature.

We extend the characterization of the TRPM8 antagonist VBJ103 with tests of selectivity, specificity and distribution, therapeutic efficacy of systemic administration against oxaliplatin-induced cold hyperalgesia and the impact of systemic administration on core body temperature (CBT). Selectivity at human TRPA1 and TRPV1 as well as in vitro safety profiling was determined. Effects of systemic administration of VBJ103 were evaluated in a model of oxaliplatin-induced cold hyperalgesia. Both peripheral and centrally mediated effects of VBJ103 on CBT were assessed with radiotelemetry. VBJ103 had no antagonist activity at TRPV1 and TRPA1, but low potency TRPA1 activation. The only safety liability detected was partial inhibition of the dopamine transporter (DAT). VBJ103 delivered subcutaneously dose-dependently attenuated cold hypersensitivity in oxaliplatin-treated mice at 3, 10 and 30 mg·kg-1 (n = 7, P < 0.05). VBJ103 (30 mg·kg-1) antinociception was influenced by neither the TRPA1 antagonist HC-030031 nor the DAT antagonist GBR12909. Subcutaneous administration of VBJ103 (3, 10 and 30 mg·kg-1, but not 100 or 300 mg·kg-1, n = 7) decreased CBT (2°C). Intraperitoneal (i.p.) administration of VBJ103 (3, 10 and 30 mg·kg-1) dose-dependently decreased CBT to an extent larger than that detected with subcutaneous administration. Intracerebroventricular (i.c.v.) administration (306 nmol/1 μL; n = 5) did not alter CBT. We achieve therapeutic efficacy with subcutaneous administration of a novel TRPM8 antagonist that attenuates deleterious influences on CBT, a side effect that has largely prevented the translation of TRPM8 as a target.

An Anti-VEGF-B Antibody Reduces Abnormal Tumor Vasculature and Enhances the Effects of Chemotherapy

The vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key regulators of blood vessel formation, including in tumors, where their deregulated function can promote the production of aberrant, leaky blood vessels, supporting tumor development. Here we investigated the VEGFR1 ligand VEGF-B, which we demonstrate to be expressed in tumor cells and in tumor stroma and vasculature across a range of tumor types. We examined the anti-VEGF-B-specific monoclonal antibody 2H10 in preclinical xenograft models of breast and colorectal cancer, in comparison with the anti-VEGF-A antibody bevacizumab. Similar to bevacizumab, 2H10 therapy was associated with changes in tumor blood vessels and intra-tumoral diffusion consistent with normalization of the tumor vasculature. Accordingly, treatment resulted in partial inhibition of tumor growth, and significantly improved the response to chemotherapy. Our studies indicate the importance of VEGF-B in tumor growth, and the potential of specific anti-VEGF-B treatment to inhibit tumor development, alone or in combination with established chemotherapies.

Direct foliar phosphorus uptake from wildfire ash

Abstract. Atmospheric particles originating from combustion byproducts (burned biomass or wildfire ash) are highly enriched in nutrients such as P, K, Ca, Mg, Fe, Mn, and Zn. Over long timescales, deposited wildfire ash particles contribute to soil fertility by replenishing soil nutrient reservoirs. However, the immediate nutritional effects of freshly deposited fire ash on plants are mostly unknown. Here, we study the influence of fire ash on plant nutrition by applying ash separately on a plant's foliage or to its substrate around the roots. We conducted experiments on chickpea model plants under ambient and elevated CO2 levels, which reflect current and future climate scenarios. We found that plants can utilize fire ash P and Ni through their leaves by direct nutrient uptake from particles captured on their foliage but not via their roots, both under ambient and elevated CO2 levels. These results indicate that over a short timescale, plants effectively uptake P from fire ash only via the foliage rather than the root pathway, which is possibly due to low bioavailability or limited contact between fire ash particles and the roots. According to many previous studies, elevated levels of CO2 will reduce the ionome of plants due to the partial inhibition of the key root uptake mechanism, thus increasing the significance of foliar nutrient uptake in a future climate. Furthermore, the role of fire ash is expected to increase in the future world, thus giving a competitive advantage to plants that can utilize fire ash P from the foliar pathway, as fire ash P is a particularly efficient and important source of P.

Oxidative phosphorylation regulates B cell effector cytokines and promotes inflammation in multiple sclerosis.

Dysregulated B cell cytokine production contributes to pathogenesis of immune-mediated diseases including multiple sclerosis (MS); however, the underlying mechanisms are poorly understood. In this study we investigated how cytokine secretion by pro-inflammatory (GM-CSF-expressing) and anti-inflammatory (IL-10-expressing) B cells is regulated. Pro-inflammatory human B cells required increased oxidative phosphorylation (OXPHOS) compared with anti-inflammatory B cells. OXPHOS reciprocally modulated pro- and anti-inflammatory B cell cytokines through regulation of adenosine triphosphate (ATP) signaling. Partial inhibition of OXPHOS or ATP-signaling including with BTK inhibition resulted in an anti-inflammatory B cell cytokine shift, reversed the B cell cytokine imbalance in patients with MS, and ameliorated neuroinflammation in a myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalitis mouse model. Our study identifies how pro- and anti-inflammatory cytokines are metabolically regulated in B cells and identifies ATP and its metabolites as a "fourth signal" that shapes B cell responses and is a potential target for restoring the B cell cytokine balance in autoimmune diseases.

Tailoring bisphosphonate-doped titanium films to optimally couple cellular responses and antibacterial activity for biomedical applications.

Titanium (Ti) is widely utilized as an implant material; nonetheless, its integration with bone tissue faces limitations due to a patient's comorbidities. To address this challenge, we employed a strategic approach involving the growth of thin films by spin-coating and surface functionalization with etidronate (ETI), alendronate (ALE), and risedronate (RIS). Our methodology involved coating of Ti cp IV disks with thin films of TiO2, hydroxyapatite (HA), and their combinations (1:1 and 1:2 v/v), followed by surface functionalization with ETI, ALE, and RIS. Bisphosphonate-doped films were evaluated in terms of surface morphology and physical-chemical properties by techniques such as electron microscopy, confocal microscopy, and x-ray photoelectron spectroscopy. The antibacterial potential of bisphosphonates alone or functionalized onto the Ti surface was tested against Staphylococcus aureus biofilms. Primary human bone mesenchymal stem cells were used to determine in vitro cell metabolism and mineralization. Although RIS alone did not demonstrate any antibacterial effect as verified by minimum inhibitory concentration assay, when Ti surfaces were functionalized with RIS, partial inhibition of Staphylococcus aureus growth was noted, probably because of the physical-chemical surface properties. Furthermore, samples comprising TiO2/HA (1:1 and 1:2 v/v) showcased an enhancement in the metabolism of nondifferentiated cells and can potentially enhance the differentiation of osteoblastic precursors. All samples demonstrated cell viability higher than 80%. Addition of hydroxyapatite and presence of bisphosphonates increase the metabolic activity and the mineralization of human bone mesenchymal cells. While these findings hold promise, it is necessary to conduct further studies to evaluate the system's performance in vivo and ensure its long-term safety. This research marks a significant stride toward optimizing the efficacy of titanium implants through tailored surface modifications.

Unconventional activation of PRKDC by TNF-α: deciphering its crucial role in Th1-mediated inflammation beyond DNA repair as part of the DNA-PK complex

BackgroundThe DNA-dependent protein kinase (DNA-PK) complex comprises a catalytic (PRKDC) and two requisite DNA-binding (Ku70/Ku80) subunits. The role of the complex in repairing double-stranded DNA breaks (DSBs) is established, but its role in inflammation, as a complex or individual subunits, remains elusive. While only ~ 1% of PRKDC is necessary for DNA repair, we reported that partial inhibition blocks asthma in mice without causing SCID.MethodsWe investigated the central role of PRKDC in inflammation and its potential association with DNA repair. We also elucidated the relationship between inflammatory cytokines (e.g., TNF-α) and PRKDC by analyzing its connections to inflammatory kinases. Human cell lines, primary human endothelial cells, and mouse fibroblasts were used to conduct the in vitro studies. For animal studies, LPS- and oxazolone-induced mouse models of acute lung injury (ALI) and delayed-type hypersensitivity (DHT) were used. Wild-type, PRKDC+/−, or Ku70+/− mice used in this study.ResultsA ~ 50% reduction in PRKDC markedly blocked TNF-α-induced expression of inflammatory factors (e.g., ICAM-1/VCAM-1). PRKDC regulates Th1-mediated inflammation, such as DHT and ALI, and its role is highly sensitive to inhibition achieved by gene heterozygosity or pharmacologically. In endothelial or epithelial cells, TNF-α promoted rapid PRKDC phosphorylation in a fashion resembling that induced by, but independent of, DSBs. Ku70 heterozygosity exerted little to no effect on ALI in mice, and whatever effect it had was associated with a specific increase in MCP-1 in the lungs and systemically. While Ku70 knockout blocked VP-16-induced PRKDC phosphorylation, it did not prevent TNF-α − induced phosphorylation of the kinase, suggesting Ku70 dispensability. Immunoprecipitation studies revealed that PRKDC transiently interacts with p38MAPK. Inhibition of p38MAPK blocked TNF-α-induced PRKDC phosphorylation. Direct phosphorylation of PRKDC by p38MAPK was demonstrated using a cell-free system.ConclusionsThis study presents compelling evidence that PRKDC functions independently of the DNA-PK complex, emphasizing its central role in Th1-mediated inflammation. The distinct functionality of PRKDC as an individual enzyme, its remarkable sensitivity to inhibition, and its phosphorylation by p38MAPK offer promising therapeutic opportunities to mitigate inflammation while sparing DNA repair processes. These findings expand our understanding of PRKDC biology and open new avenues for targeted anti-inflammatory interventions.

EZH2 mutations in follicular lymphoma distort H3K27me3 profiles and alter transcriptional responses to PRC2 inhibition

Mutations in chromatin regulators are widespread in cancer. Among them, the histone H3 lysine 27 methyltransferase Polycomb Repressive Complex 2 (PRC2) shows distinct alterations according to tumor type. This specificity is poorly understood. Here, we model several PRC2 alterations in one isogenic system to reveal their comparative effects. Focusing then on lymphoma-associated EZH2 mutations, we show that Ezh2Y641F induces aberrant H3K27 methylation patterns even without wild-type Ezh2, which are alleviated by partial PRC2 inhibition. Remarkably, Ezh2Y641F rewires the response to PRC2 inhibition, leading to induction of antigen presentation genes. Using a unique longitudinal follicular lymphoma cohort, we further link EZH2 status to abnormal H3K27 methylation. We also uncover unexpected variability in the mutational landscape of successive biopsies, pointing to frequent co-existence of different clones and cautioning against stratifying patients based on single sampling. Our results clarify how oncogenic PRC2 mutations disrupt chromatin and transcription, and the therapeutic vulnerabilities this creates.

Investigating the role of itaconate in macrophage activation and oxidative stress injury in sepsis-associated acute kidney injury.

Sepsis may be linked to oxidative stress and can be controlled by itaconate, an activator of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Nevertheless, the itaconate impact on sepsis-associated acute kidney injury (SA-AKI) has yet to be definitively established. We employed SA-AKI mouse model through a cecal ligation and puncture (CLP) procedure for the in vivo investigation of the potential nephroprotective effect of itaconate in this study. A plasmid was transfected into RAW264.7 cells to examine the Nrf2 pathway function after itaconate administration. Finally, the immune-responsive gene 1-knockout (IRG1-/-) mice were used to study the itaconate impacts on oxidative stress-induced SA-AKI. We have shown that 4-octyl itaconate (OI) significantly reduced CD11b-positive macrophage aggregation and activated the Nrf2 pathway in the bone marrow-derived macrophages (BMDM). The impacts of Nrf2 inhibitor ML385 on the anti-inflammatory and antioxidant properties of itaconate were found to be partial. OI inhibited lipopolysaccharide-induced oxidative stress injury in RAW264.7 macrophages and activated Nrf2 in the nucleus to hinder the expression of nuclear factor kappa B p65, thereby suppressing oxidative stress injury in the macrophages. Additionally, the introduction of the transfected plasmid resulted in a partial inhibition of the anti-inflammatory impact of itaconate. The kidney injury caused by sepsis exhibited greater severity in the IRG1-/- mice than in the wild type mice. Exogenous OI partially attenuated the kidney injury induced by sepsis in the IRG1-/- mice and suppressed the oxidative stress injury in macrophages. This investigation offers new proof to support the itaconate function in the development and progression of SA-AKI and shows a new possible therapeutic agent for the SA-AKI treatment.

Energy Blocker Lonidamine Reverses Nimustine Resistance in Human Glioblastoma Cells through Energy Blockade, Redox Homeostasis Disruption, and O6-Methylguanine-DNA Methyltransferase Downregulation: In Vitro and In Vivo Validation.

Tumor resistance seriously hinders the clinical application of chloroethylnitrosoureas (CENUs), such as O6-methylguanine-DNA methylguanine (MGMT), which can repair O6-alkyl lesions, thereby inhibiting the formation of cytotoxic DNA interstrand cross-links (ICLs). Metabolic differences between tumor and normal cells provide a biochemical basis for novel therapeutic strategies aimed at selectively inhibiting tumor energy metabolism. In this study, the energy blocker lonidamine (LND) was selected as a chemo-sensitizer of nimustine (ACNU) to explore its potential effects and underlying mechanisms in human glioblastoma in vitro and in vivo. A series of cell-level studies showed that LND significantly increased the cytotoxic effects of ACNU on glioblastoma cells. Furthermore, LND plus ACNU enhanced the energy deficiency by inhibiting glycolysis and mitochondrial function. Notably, LND almost completely downregulated MGMT expression by inducing intracellular acidification. The number of lethal DNA ICLs produced by ACNU increased after the LND pretreatment. The combination of LND and ACNU aggravated cellular oxidative stress. In resistant SF763 mouse tumor xenografts, LND plus ACNU significantly inhibited tumor growth with fewer side effects than ACNU alone. Finally, we proposed a new "HMAGOMR" chemo-sensitizing mechanism through which LND may act as a potential chemo-sensitizer to reverse ACNU resistance in glioblastoma: moderate inhibition of hexokinase (HK) activity (H); mitochondrial dysfunction (M); suppressing adenosine triphosphate (ATP)-dependent drug efflux (A); changing redox homeostasis to inhibit GSH-mediated drug inactivation (G) and increasing intracellular oxidative stress (O); downregulating MGMT expression through intracellular acidification (M); and partial inhibition of energy-dependent DNA repair (R).

Contrasting consequences of podocyte insulin-like growth factor 1 receptor inhibition

Insulin signaling to the glomerular podocyte via the insulin receptor (IR) is critical for kidney function. In this study we show that near-complete knockout of the closely related insulin-like growth factor 1 receptor (IGF1R) in podocytes is detrimental, resulting in albuminuria invivo and podocyte cell death invitro. In contrast, partial podocyte IGF1R knockdown confers protection against doxorubicin-induced podocyte injury. Proteomic analysis of cultured podocytes revealed that while near-complete loss of podocyte IGF1R results in the downregulation of mitochondrial respiratory complex I and DNA damage repair proteins, partial IGF1R inhibition promotes respiratory complex expression. This suggests that altered mitochondrial function and resistance to podocyte stress depends on the level of IGF1R suppression, the latter determining whether receptor inhibition is protective or detrimental. Our work suggests that the partial suppression of podocyte IGF1R could have therapeutic benefits in treating albuminuric kidney disease.