Protein Kinase Research Articles

Illuminating the dark kinome: utilizing multiplex peptide activity arrays to functionally annotate understudied kinases

Protein kinases are critical components of a myriad biological processes and strongly associated with various diseases. While kinase research has been a point of focus in biomedical research for several decades, a large portion of the kinome is still considered understudied or “dark,” because prior research is targeted towards a subset of kinases with well-established roles in cellular processes. We present an empirical and in-silico hybrid workflow to extend the functional knowledge of understudied kinases. Utilizing multiplex peptide activity arrays and robust in-silico analyses, we extended the functional knowledge of five dark tyrosine kinases (AATK, EPHA6, INSRR, LTK, TNK1) and explored their roles in schizophrenia, Alzheimer’s dementia (AD), and major depressive disorder (MDD). Using this hybrid approach, we identified 195 novel kinase-substrate interactions with variable degrees of affinity and linked extended functional networks for these kinases to biological processes that are impaired in psychiatric and neurological disorders. Biochemical assays and mass spectrometry were used to confirm a putative substrate of EPHA6, an understudied dark tyrosine kinase. We examined the EPHA6 network and knowledgebase in schizophrenia using reporter peptides identified and validated from the multi-plex array with high affinity for phosphorylation by EPHA6. Identification and confirmation of putative substrates for understudied kinases provides a wealth of actionable information for the development of new drug treatments as well as exploration of the pathophysiology of disease states using signaling network approaches.

Protein kinase 2 of the giant sarcomeric protein UNC-89 regulates mitochondrial morphology and function

UNC-89 is a giant sarcomeric M-line protein required for sarcomere organization and optimal muscle function. UNC-89 contains two protein kinase domains, PK1 and PK2, separated by an elastic region. Here we show that PK2 is a canonical kinase expected to be catalytically active. C. elegans expressing UNC-89 with a lysine to alanine (KtoA) mutation to inactivate PK2 have normally organized sarcomeres and SR, and normal muscle function. PK2 KtoA mutants have fragmented mitochondria, correlated with more mitochondrially-associated DRP-1. PK2 KtoA mutants have increased ATP levels, increased glycolysis and altered levels of electron transport chain complexes. Muscle mitochondria show increased complex I and decreased complex II basal respiration, each of which cannot be uncoupled. This suggests that mutant mitochondria are already uncoupled, possibly resulting from an increased level of the uncoupling protein, UCP-4. Our results suggest signaling from sarcomeres to mitochondria, to help match energy requirements with energy production.

Maternal Broccoli Powder Intake Ameliorates Insulin Resistance and Inflammation via AMPK/mTOR Pathway in the Livers of High-Fructose-Fed Male Rat Offspring Exposed to Maternal Protein Restriction.

Sub-optimal prenatal conditions such as maternal undernutrition during pregnancy and lactation posit high risks of adult metabolic diseases. High fructose intake causes insulin resistance and liver inflammation contributing to metabolic diseases. However, food-based preventive measure for these metabolic diseases in the offspring is under-researched. This study aims to investigate the effect of maternal broccoli powder (BP) intake during lactation on insulin resistance and liver inflammation in high-fructose-diet-fed adult male offspring exposed to maternal protein restriction. Pregnant Wistar rats are provided normal protein (NP) or low protein (LP) diets and 0% or 0.74% BP-containing NP diets and 0% or 0.74% BP-containing LP diet during lactation. At weaning, offspring receiving water (W) or 10% fructose solution (Fr) are assigned into six groups: NP/NP/W, NP/NP/Fr, NP/NPBP/Fr, LP/LP/W, LP/LP/Fr, and LP/LPBP/Fr. At week 13, plasma insulin, macrophage infiltration, activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) phosphorylation, and autophagy flux markers are examined. LP/LPBP/Fr shows lower insulin levels and Homeostatic model assessment for insulin resistance (HOMA-IR) values than LP/LP/Fr. Liver macrophage infiltration are decreased in LP/LPBP/Fr. LP/LPBP/Fr exhibits upregulated AMPK phosphorylation, downregulated mTOR phosphorylation, and increased Microtubule-associated protein1A/1B-light chain 3B-II (LC3B-II) levels. Maternal BP intake during lactation ameliorates insulin resistance and inflammation in the livers of adult offspring on a high-fructose diet from LP mothers.

Transcriptome wide changes in long noncoding RNAs in diabetic ischemic heart disease

More than 10% of adults in the United States have type 2 diabetes mellitus (DM) with a 2–4 times higher prevalence of ischemic heart disease than the non-diabetics. Despite extensive research approaches to limit this life-threatening condition have proven unsuccessful, highlighting the need for understanding underlying molecular mechanisms. Long noncoding RNAs (lncRNAs), which regulate gene expression by acting as signals, decoys, guides, or scaffolds have been implicated in diverse cardiovascular conditions. However, their role in ischemic heart disease in DM remains poorly understood. We provide new insights into the lncRNA expression profile after ischemic heart disease in DM mice. We performed unbiased RNA sequencing of well-characterized type 2 DM model db/db mice or its control db/+ subjected to sham or MI surgery. Computational analysis of the RNA sequencing of these LV tissues identified several differentially expressed lncRNAs between (db/db sham vs. db/db MI) including Gm19522 and Gm8075. lncRNA Gm-19522 may regulate DNA replication via DNA protein kinases, while lncRNA Gm-8075 is associated with cancer gene dysregulation and PI3K/Akt pathways. Thus, the downregulation of lncRNAs Gm19522 and Gm8075 post-MI may serve as potential biomarkers or novel therapeutic targets to improve cardiac repair/recovery in diabetic ischemic heart disease.

Population-wide DNA methylation polymorphisms at single-nucleotide resolution in 207 cotton accessions reveal epigenomic contributions to complex traits.

DNA methylation plays multiple regulatory roles in crop development. However, the relationships of methylation polymorphisms with genetic polymorphisms, gene expression, and phenotypic variation in natural crop populations remain largely unknown. Here, we surveyed high-quality methylomes, transcriptomes, and genomes obtained from the 20-days-post-anthesis (DPA) cotton fibers of 207 accessions and extended the classical framework of population genetics to epigenetics. Over 287 million single methylation polymorphisms (SMPs) were identified, 100 times more than the number of single nucleotide polymorphisms (SNPs). These SMPs were significantly enriched in intragenic regions while depleted in transposable elements. Association analysis further identified a total of 5,426,782 cis-methylation quantitative trait loci (cis-meQTLs), 5078 cis-expression quantitative trait methylation (cis-eQTMs), and 9157 expression quantitative trait loci (eQTLs). Notably, 36.39% of cis-eQTM genes were not associated with genetic variation, indicating that a large number of SMPs associated with gene expression variation are independent of SNPs. In addition, out of the 1715 epigenetic loci associated with yield and fiber quality traits, only 36 (2.10%) were shared with genome-wide association study (GWAS) loci. The construction of multi-omics regulatory networks revealed 43 cis-eQTM genes potentially involved in fiber development, which cannot be identified by GWAS alone. Among these genes, the role of one encoding CBL-interacting protein kinase 10 in fiber length regulation was successfully validated through gene editing. Taken together, our findings prove that DNA methylation data can serve as an additional resource for breeding purposes and can offer opportunities to enhance and expedite the crop improvement process.

AIBP Protects Müller Glial Cells Against Oxidative Stress-Induced Mitochondrial Dysfunction and Reduces Retinal Neuroinflammation.

Glaucoma, an optic neuropathy with the loss of retinal ganglion cells (RGCs), is a leading cause of irreversible vision loss. Oxidative stress and mitochondrial dysfunction have a significant role in triggering glia-driven neuroinflammation and subsequent glaucomatous RGC degeneration in the context of glaucoma. It has previously been shown that apolipoprotein A-I binding protein (APOA1BP or AIBP) has an anti-inflammatory function. Moreover, Apoa1bp-/- mice are characterized by retinal neuroinflammation and RGC loss. In this study, we found that AIBP deficiency exacerbated the oxidative stress-induced disruption of mitochondrial dynamics and function in the retina, leading to a further decline in visual function. Mechanistically, AIBP deficiency-induced oxidative stress triggered a reduction in glycogen synthase kinase 3β and dynamin-related protein 1 phosphorylation, optic atrophy type 1 and mitofusin 1 and 2 expression, and oxidative phosphorylation, as well as the activation of mitogen-activated protein kinase (MAPK) in Müller glia dysfunction, leading to cell death and inflammatory responses. In vivo, the administration of recombinant AIBP (rAIBP) effectively protected the structural and functional integrity of retinal mitochondria under oxidative stress conditions and prevented vision loss. In vitro, incubation with rAIBP safeguarded the structural integrity and bioenergetic performance of mitochondria and concurrently suppressed MAPK activation, apoptotic cell death, and inflammatory response in Müller glia. These findings support the possibility that AIBP promotes RGC survival and restores visual function in glaucomatous mice by ameliorating glia-driven mitochondrial dysfunction and neuroinflammation.

SUMOylation of Warts kinase promotes neural stem cell reactivation

A delicate balance between neural stem cell (NSC) quiescence and proliferation is important for adult neurogenesis and homeostasis. Small ubiquitin-related modifier (SUMO)-dependent post-translational modifications cause rapid and reversible changes in protein functions. However, the role of the SUMO pathway during NSC reactivation and brain development is not established. Here, we show that the key components of the SUMO pathway play an important role in NSC reactivation and brain development in Drosophila. Depletion of SUMO/Smt3 or SUMO conjugating enzyme Ubc9 results in notable defects in NSC reactivation and brain development, while their overexpression leads to premature NSC reactivation. Smt3 protein levels increase with NSC reactivation, which is promoted by the Ser/Thr kinase Akt. Warts/Lats, the core protein kinase of the Hippo pathway, can undergo SUMO- and Ubc9-dependent SUMOylation at Lys766. This modification attenuates Wts phosphorylation by Hippo, leading to the inhibition of the Hippo pathway, and consequently, initiation of NSC reactivation. Moreover, inhibiting Hippo pathway effectively restores the NSC reactivation defects induced by SUMO pathway inhibition. Overall, our study uncovered an important role for the SUMO-Hippo pathway during Drosophila NSC reactivation and brain development.

SESN2 Ameliorates Dihydrotestosterone-induced Human Ovarian Granulosa Cell Damage by Activating AMPK/ULK1-mediated Mitophagy.

Sestrin 2 (SESN2) has been reported to participate in the regulation of granulosa cell function in ovarian tissues. However, the role of SESN2 in polycystic ovarian syndrome (PCOS) is still incompletely understood. Here, we investigated the functional role and mechanism of SESN2 in dihydrotestosterone (DHT)-induced granulosa cells. In this study, DHT was utilized to induce PCOS cell model and the AMP-activated protein kinase (AMPK) inhibitor Compound C (CC) was utilized to inhibit the AMPK pathway. qRT-PCR was performed to detect the expression of SESN2 in HGLS cells. Cell apoptosis was evaluated by flow cytometry. Oxidative stress was detected by DCFH-DA staining, superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) kits. The expression of SESN2, cell apoptosis, oxidative stress, mitophagy and AMPK/ULK1 signaling-related proteins were measured by western blot. The results showed that SESN2 was downregulated in DHT-induced granulosa cells. Overexpression of SESN2 inhibited the DHT-induced apoptosis and oxidative stress of HGLS cells. DHT induction aggravated HGLS cell apoptosis and oxidative stress. SESN2 overexpression inhibited the DHT-induced apoptosis and oxidative stress of HGLS cells. In addition, overexpression of SESN2 activated the AMPK/ULK1 signaling pathway and promoted mitophagy. Treatment of CC reversed the regulatory effect of SESN2 on mitophagy. CC also reversed the influences of SESN2 overexpression on apoptosis and oxidative stress in DHT-induced HGLS cells. Overall, SESN2 suppressed DHT-induced apoptosis and oxidative stress in PCOS through AMPK/ULK1-mediated mitophagy.

The Effects of Warm Acupuncture on the Expression of AMPK in High-Fat Diet-Induced MAFLD Rats.

This study investigated the effects of acupuncture and warm acupuncture on the expression and mechanism of the AMP-activated protein kinase (AMPK) signalling pathway associated with lipid accumulation in the liver tissue of rats with metabolic dysfunction-associated fatty liver disease (MAFLD) induced by a high-fat diet. Sprague-Dawley rats were categorised into four groups: control (CON), untreated MAFLD (MAFLD), and two MAFLD groups treated with acupuncture (ACU) and warm acupuncture (WA). The treatment groups underwent 16 application sessions over 8 weeks at the SP9 and BL18 acupoints. We measured the expression levels of AMPK, sterol regulatory element-binding protein1 (SREBP1), acetyl-coenzyme A carboxylase (ACC), peroxisome proliferator-activated receptorα (PPARα), carnitine palmitoyltransferase1 (CPT1), and CPT2. AMPK was activated in both ACU and WA groups. WA downregulated both SREBP1 and ACC expression at the protein level, whereas the acupuncture treatment downregulated SREBP1 expression. Additionally, WA selectively induced the activation of signalling pathways related to AMPK, PPARα, CPT1, and CPT2 at the mRNA level. Histological observations confirmed that fat accumulation was reduced in both the ACU and the WA groups compared to the MAFLD group. The WA treatment-promoted amelioration of HFD-induced MAFLD may be related to the activation of the AMPK/SREBP1/ACC pathway in the liver.

Proteomic analysis of giant panda testicular tissue of different age groups

Background The reproductive ability of male giant pandas has been a major complicating factor in the ex-situ conservation of the species. While it is well known that the testis produces sperm and secretes androgens, a process that requires precise regulation of various proteins, at present, there has been no systematic study on the composition of proteins in the testis of the giant pandas. Therefore, this study aims to apply proteomics to explore the regulation of proteins in the testes of giant pandas. Methods Samples from the testes of three giant pandas (22 years, 18 years, 8 days) were studied to assess the protein’s function. A label-free quantitative method was used to isolate testicular proteins from each male, 139,039 peptides and 11,435 proteins were obtained. Results Gene Ontology (GO) annotates most of the proteins involved in the processes of protein phosphorylation, oxidation-reduction, proteolysis, and signal transduction. KEGG pathway indicated that most of the proteins were involved in the pathway of signal transduction, transport, and catabolism. The protein kinase and WD40 repeats were involved in protein-protein interaction, which in turn regulates gene expression in the testicular tissue of giant pandas. Conclusions This study is the first to conduct an in-depth proteomic analysis of testicular tissue in giant pandas. The results revealed the important role of proteins in testicular tissue on spermatogenesis, testosterone production, and testicular microenvironment, providing clues for further research on male giant panda reproduction.

Molecular mechanism of ectopic lipid accumulation induced by methylglyoxal via activation of the NRF2/PI3K/AKT pathway implicates renal lipotoxicity caused by diabetes mellitus.

Patients with chronic kidney disease (CKD) have a high incidence of dyslipidemia comprising high triglyceride (TG) and low high-density lipoprotein (HDL)-cholesterol levels. An abnormal increase of TGs within cells can lead to intracellular lipid accumulation. In addition to dyslipidemia, hyperglycemia in diabetes may elicit ectopic lipid deposition in non-adipose tissues. Hyperglycemia increases intracellular levels of methylglyoxal (MG) leading to cellular dysfunction. A deficit of glyoxalase I (GLO1) contributes to dicarbonyl stress. Whether dicarbonyl stress induced by MG causes renal lipotoxicity through alteration of lipid metabolism signaling is still unknown. In this study, mice with high fat diet-induced diabetes were used to investigate the renal pathology induced by MG. NRK52E cells treated with MG were further used in vitro to delineate the involvement of lipogenic signaling. After treatment with MG for 12 weeks, plasma TG levels, renal fatty changes, and tubular injuries were aggravated in diabetic mice. In NRK52E cells, MG activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and sterol regulatory element-binding protein 1 (SREBP1), resulting in stimulation of fatty acid synthase. The intracellular accumulation of lipid droplets was mainly contributed by TGs, which increased the oxidative stress accompanied by high Nrf2 expression. In addition, MG time-dependently activated cyclin D, cyclin-dependent kinase 4 (CDK4), and cleaved caspase-3, evidencing that G0/G1 arrest was associated with apoptosis of NRK52E cells. In conclusion, our studies revealed the mechanism of lipotoxicity caused by MG. The target of such dicarbonyl stress may become a promising therapy for diabetic CKD.

Baicalein Ameliorates Insulin Resistance of HFD/STZ Mice Through Activating PI3K/AKT Signal Pathway of Liver and Skeletal Muscle in a GLP-1R-Dependent Manner.

Insulin resistance (IR) is the principal pathophysiological change occurring in diabetes mellitus (DM). Baicalein, a bioactive flavonoid primarily extracted from the medicinal plant Scutellaria baicalensis Georgi, has been shown in our previous research to be a potential natural glucagon-like peptide-1 receptor (GLP-1R) agonist. However, the exact therapeutic effect of baicalein on DM and its underlying mechanisms remain elusive. In this study, we investigated the therapeutic effects of baicalein on diabetes and sought to clarify its underlying molecular mechanisms. Our results demonstrated that baicalein improves hyperglycemic, hyperinsulinemic, and glucometabolic disorders in mice with induced diabetes via GLP-1R. This was confirmed by the finding that baicalein's effects on improving IR were largely diminished in mice with whole-body Glp1r ablation. Complementarily, network pharmacology analysis highlighted the pivotal involvement of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) insulin signaling pathway in the therapeutic actions of baicalein on IR. Our mechanism research significantly confirmed that baicalein mitigates hepatic and muscular IR through the PI3K/AKT signal pathway, both in vitro and in vivo. Furthermore, we demonstrated that baicalein enhances glucose uptake in skeletal muscle cells under IR conditions through the Ca2+/calmodulin-dependent protein kinase II (CaMKII)-adenosine 5'-monophosphate-activated protein kinase (AMPK)-glucose transporter 4 (GLUT4) signaling pathway in a GLP-1R-dependent manner. In conclusion, our findings confirm the therapeutic effects of baicalein on IR and reveal that it improves IR in liver and muscle tissues through the PI3K/AKT insulin signaling pathway in a GLP-1R dependent manner. Moreover, we clarified that baicalein enhances the glucose uptake in skeletal muscle tissue through the Ca2+/CaMKII-AMPK-GLUT4 signal pathway.

Follistatin drives neuropathic pain in mice through IGF1R signaling in nociceptive neurons.

Neuropathic pain is a debilitating chronic condition that lacks effective treatment. The role of cytokine- and chemokine-mediated neuroinflammation in its pathogenesis has been well documented. Follistatin (FST) is a secreted protein known to antagonize the biological activity of cytokines in the transforming growth factor-β (TGF-β) superfamily. The involvement of FST in neuropathic pain and the underlying mechanism remain largely unknown. Here, we report that FST was up-regulated in A-fiber sensory neurons after spinal nerve ligation (SNL) in mice. Inhibition or deletion of FST alleviated neuropathic pain and reduced the nociceptive neuron hyperexcitability induced by SNL. Conversely, intrathecal or intraplantar injection of recombinant FST, or overexpression of FST in the dorsal root ganglion (DRG) neurons, induced pain hypersensitivity. Furthermore, exogenous FST increased neuronal excitability in nociceptive neurons. The biolayer interferometry (BLI) assay and coimmunoprecipitation (co-IP) demonstrated direct binding of FST to the insulin-like growth factor-1 receptor (IGF1R), and IGF1R inhibition reduced FST-induced activation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT), as well as neuronal hyperexcitability. Further co-IP analysis revealed that the N-terminal domain of FST exhibits the highest affinity for IGF1R, and blocking this interaction with a peptide derived from FST attenuated Nav1.7-mediated neuronal hyperexcitability and neuropathic pain after SNL. In addition, FST enhanced neuronal excitability in human DRG neurons through IGF1R. Collectively, our findings suggest that FST, released from A-fiber neurons, enhances Nav1.7-mediated hyperexcitability of nociceptive neurons by binding to IGF1R, making it a potential target for neuropathic pain treatment.

Mycobacterium avium inhibits protein kinase C and MARCKS phosphorylation in human cystic fibrosis and non-cystic fibrosis cells.

In cystic fibrosis (CF), there is abnormal translocation and function of the cystic fibrosis transmembrane conductance regulator (CFTR) and an upregulation of the epithelial sodium channel (ENaC). This leads to hyperabsorption of sodium and fluid from the airway, dehydrated mucus, and an increased risk of respiratory infections. In this study, we performed a proteomic assessment of differentially regulated proteins from CF and non-CF small airway epithelial cells (SAEC) that are sensitive to Mycobacterium avium. CF SAEC and normal non-CF SAEC were infected with M. avium before the cells were harvested for protein. Protein kinase C (PKC) activity was greater in the CF cells compared to the non-CF cells, but the activity was significantly attenuated in both cell types after infection with M. avium compared to vehicle. Western blot and densitometric analysis showed a significant increase in cathepsin B protein expression in M. avium infected CF cells. Myristoylated alanine rich C-kinase substrate (MARCKS) protein was one of several differentially expressed proteins between the groups that was identified by mass spectrometry-based proteomics. Total MARCKS protein expression was greater in CF cells compared to non-CF cells. Phosphorylation of MARCKS at serine 163 was also greater in CF cells compared to non-CF cells after treating both groups of cells with M. avium. Taken together, MARCKS protein is upregulated in CF cells and there is decreased phosphorylation of the protein due to a decrease in PKC activity and presumably increased cathepsin B mediated proteolysis of the protein after M. avium infection.

Cryoprotective Potential of Theobromine in the Improvement of the Post-Thaw Quality of Bovine Spermatozoa.

Theobromine (TBR) is a methylxanthine known for its bronchodilatory and stimulatory effects. This research evaluated the vitality, capacitation patterns, oxidative characteristics, microbial profile and expression of capacitation-associated proteins (CatSper1/2, sodium bicarbonate cotransporter [NBC], protein kinases A [PKA] and C [PKC] and adenylate cyclase 10 [ADCY10]) in cryopreserved bovine spermatozoa (n = 30) in the absence (cryopreserved control [CtrlC]) or presence of different TBR concentrations (12.5, 25, and 50 µM) in egg yolk extender. Fresh ejaculate served as a negative control (CtrlN). Significant post-thaw maintenance of the sperm motility, membrane and DNA integrity and mitochondrial activity (p < 0.001) were recorded following the administration of 25 μM and 50 μM TBR, then compared to CtrlC. All groups supplemented with TBR exhibited a significantly lower percentage of prematurely capacitated spermatozoa (p < 0.001) than CtrlC. Significantly decreased levels of global reactive oxygen species (ROS), hydrogen peroxide and hydroxyl radicals were observed in the presence of 25 μM and 50 μM TBR (p < 0.01). Western blot analysis revealed that supplementation with 50 μM TBR significantly prevented the loss of NBC and ADCY10 (p < 0.01), while all TBR doses stabilized the levels of PKC (p < 0.05 at 50 μM TBR; p < 0.001 at 12.5 μM and 25 μM TBR). In summary, we suggest that TBR is effective in protecting the spermatozoa during the cryopreservation process through its potential to stimulate energy synthesis while preventing ROS overproduction and the loss of proteins involved in the sperm activation process.

Role of SIK1 in tumors: Emerging players and therapeutic potentials (Review).

Salt‑induced kinase 1 (SIK1) is a serine/threonine protein kinase that is a member of the AMP‑activated protein kinase family. SIK is catalytically activated through its phosphorylation by the upstream kinase LKB1. SIK1 has been reported to be associated with numerous types of cancer. The present review summarizes the structure, regulatory factors and inhibitors of SIK1, and also describes how SIK1 is a signal regulatory factor that fulfills connecting roles in various signal regulatory pathways. Furthermore, the anti‑inflammatory effects of SIK1 during the early stage of tumor occurrence and its different regulatory effects following tumor occurrence, are summarized, and through collating the tumor signal regulatory mechanisms in which SIK1 participates, it has been demonstrated that SIK1 acts as a necessary node in cancer signal transduction. In conclusion, SIK1 is discussed independent of the SIKs family, its research results and recent progress in oncology are summarized in detail with a focus on SIK1, and its potential as a therapeutic target is highlighted, underscoring the need for SIK1‑targeted regulatory strategies in future cancer therapy.

Hypoxia activates FGF-23-ERK / MAPK signaling pathway in ischemia-reperfusion induced acute kidney injury.

Both hypoxia and fibroblast growth factor-23 (FGF-23) are key factors in ischemia-reperfusion (I/R)-induced acute kidney injury (AKI). This study aimed to explore the relationship between hypoxia and FGF-23 in AKI. An I/R-AKI animal model was established using male BALB/c mice. HK-2 cells, a part of the human proximal tubular epithelial cell line, were subjected to hypoxia/reoxygenation (H/R). qPCR was used to measure FGF-23 and HIF-1α, ELISA was used to measure inflammatory and oxidative stress cytokines. Western blotting used to measure the phosphorylation of ERK level. In I/R mice, the levels of interleukin-6 (IL-6), tumor necrosis factor (TNF-α), malondialdehyde (MDA), and the phosphorylation of extracellular signal-regulated kinase (ERK) were increased, whereas the levels of interleukin-10 (IL-10), superoxide dismutase (SOD), glutathione peroxidase (GPx), and klotho were decreased, compared to the sham operated mice. Silencing the FGF-23 expression in I/R mice normalized the levels of IL-6, IL-10, TNF-α, MDA, SOD, Gpx, and ERK phosphorylation (p-ERK). In HK-2 cells, hypoxia-reperfusion (H/R) elevated the levels of IL-6, TNF-α, MDA, and ERK phosphorylation, but reduced IL-10, SOD, GPx, and klotho levels. Hypoxia induced apoptosis in HK-2 cells but silencing of FGF-23 expression blocked the effects of hypoxia on cell apoptosis, proinflammatory factors levels, oxidative stress response, and p-ERK levels. FGF-23 is a key molecule in AKI, and hypoxia plays a crucial role in AKI by inducing cell apoptosis; however, its role is regulated by FGF-23. FGF-23 affects oxidative stress and the inflammatory response of kidney tissues by activating the ERK/mitogen-activated protein kinase (MAPK) signaling pathway.

Anti-Inflammatory Potential of Costus speciosus rhizome Bioactive Phytochemicals: A Combined GC-MS and Computational Approach Targeting TLR-4 Signaling.

Plants represent a rich reservoir of bioactive compounds with established therapeutic value in diverse diseases. Notably, the Toll-like receptor-4 (TLR-4) signaling pathway plays a pivotal role in inflammation. Upon engagement with pro-inflammatory ligands like lipopolysaccharide, TLR-4 triggers downstream cascades involving nuclear factor ĸappa B and mitogen- activated protein kinases. This signaling cascade ultimately dictates the onset and progression of inflammatory diseases. Therefore, targeting TLR-4 signaling offers a promising therapeutic approach for managing inflammatory disorders. This study investigated the potential of Costus speciosus rhizome phytocompounds, a traditional medicinal plant, as novel as modulators of TLR-4 signaling, highlighting their mechanisms of action and potential clinical applications. In the present study, 18 phytocompounds isolated from the rhizome of Costus speciosus, were studied against TLR-4/AP-1 signaling, which is implicated in the inflammatory process using a computational approach. The compounds exhibited binding affinities ranging from -4.087 to -8.93 kcal/mol with the TLR-4 protein due to the formation of multiple intermolecular interactions. Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, methyl ester (compound 7) exhibited exceptional binding energy (-8.93 kcal/mol), indicating strong affinity for the TLR-4 protein. Additionally, compound 7 displayed favorable ADMET properties, suggesting promising drug development potential. Molecular dynamics simulations confirmed the stability of the compound 7-TLR4 complex, further supporting its ability to modulate TLR-4 signaling. These findings highlight the therapeutic potential of Costus speciosus phytocompounds, particularly compound 7, as potent anti-inflammatory modulators. Further research is warranted to validate their anti-inflammatory and neuroprotective effects in pre-clinical models, paving the way for their development as novel therapeutic agents for inflammatory diseases.

Negative regulation of APC/C activation by MAPK-mediated attenuation of Cdc20Slp1 under stress

Mitotic anaphase onset is a key cellular process tightly regulated by multiple kinases. The involvement of mitogen-activated protein kinases (MAPKs) in this process has been established in Xenopus egg extracts. However, the detailed regulatory cascade remains elusive, and it is also unknown whether the MAPK-dependent mitotic regulation is evolutionarily conserved in the single-cell eukaryotic organisms such as fission yeast (Schizosaccharomyces pombe). Here, we show that two MAPKs in S. pombe indeed act in concert to restrain anaphase-promoting complex/cyclosome (APC/C) activity upon activation of the spindle assembly checkpoint (SAC). One MAPK, Pmk1, binds to and phosphorylates Slp1Cdc20, the co-activator of APC/C. Phosphorylation of Slp1Cdc20 by Pmk1, but not by Cdk1, promotes its subsequent ubiquitylation and degradation. Intriguingly, Pmk1-mediated phosphorylation event is also required to sustain SAC under environmental stress. Thus, our study establishes a new underlying molecular mechanism of negative regulation of APC/C by MAPK upon stress stimuli, and provides a previously unappreciated framework for regulation of anaphase entry in eukaryotic cells.

Inspecting the potential of thymol as a therapeutic agent for treating Alzheimer's disease

Thymol (2-isopropyl-5-methylphenol) is the main monoterpene phenol occurring in essential oils isolated from plants, like thyme, belonging to the Lemnaceae family.1 Due to its antioxidant, free radical scavenging, anti-inflammatory, analgesic, antispasmodic, antibacterial, antifungal and antiseptic properties, thymol has been used since ancient times for therapeutic purposes.2 This letter specifically focuses on using thymol in treating Alzheimer’s disease. Alzheimer’s disease is a neurodegenerative disorder which is caused due to the extracellular accumulation of amyloid B (AB) plaques and intracellular aggregations of neurofibrillary tangles (NFTs) formed due to hyperphosphorylation of microtubule associated t (tau) protein. The accumulation of these substances in various parts of the brain causes neuronal damage and death.3 Due to its free radical scavenging and antioxidant capabilities, thymol is able to scavenge the reactive oxygen species produced by the amyloid aggregates, thus attenuating the potential oxidative damage that they would cause. Thymol can also alleviate protein kinase C activity as a memory-related protein.4 thymol has proved to reduce the cognitive defects and was also found to alleviate learning and memory impairment in rat models.5,6 Although thymol has a lot of beneficial effects against cognitive impairment caused by Alzheimer’s, all of the experiments have been done on rat models; hence thymol’s therapeutic potentials in modulating and preventing Alzheimer in humans need to be fully explored.