Signaling Molecules Research Articles

Level of tryptophan signaling molecules in children with different dynamics of obesity development

The high incidence of obesity in children is an extremely pressing problem in the modern health care system of many countries. There is an increase in the incidence of obesity in children in Russia, which is dangerous not only due to the development of somatic concomitant pathologies, but also to a violation of the social adaptation of children. Without a doubt, the search for early biochemical indicators of stabilization and progress of obesity in older age is very important for the formation of a risk group and timely prevention of the development of obesity and its complications. Our study showed that when assessing the various dynamics of obesity development, it is necessary to take into account the gender of the child, which is ignored in many cases. A decrease in serum serotonin concentrations may be considered as an indicator associated with the stabilization or progression of obesity in girls. Whereas in boys prone to stabilization and/or progression of obesity, a reduced serum level of indole-3-acrylate may act as a predictor marker.

Abstract B038: Establishing a screening platform to identify key signaling molecules regulating cold tumor formation through immune evasion and exclusion

Abstract Many trial data have shown that cancer immunotherapy can successfully induce long lasting anti-cancer immune responses and increased the survival rate of cancer patients. One of the key challenges facing cancer immunotherapy is the low response rate of cancer patients to immunotherapy, suggesting that these cancer patients may have acquired resistance toward immunotherapy before treatments. Therefore, there is an unmet need for identifying the underlying mechanisms that promote resistance. One important hypothesis is that immune-excluded tumors (so called cold tumors) that lack of functional T cells have been often found in cancer patients who cannot respond well to cancer immunotherapy. To address this, we have successfully established a preclinical model for cold lung tumors, conducted RNA-seq, performed hallmark gene set enrichment analysis (GSEA) on cold tumor cells sorted in vivo, and identified several candidates associated with epithelial-mesenchymal transition, Wnt signaling, type I and II interferon (IFN) signaling, and p53 signaling. We hypothesize that their roles may either promote or inhibit the formation of cold tumors. One of the molecular candidates we identified, a molecule designated as IRC001, represents a crucial proof of concept for our experimental tumor model. We have unveiled a novel role for IRC001 in enhancing anti-tumor immunity, leading to the transformation of cold tumors into hot tumors and facilitating swift tumor regression through pathways reliant on T cells and type I IFN signaling. Our mechanistic studies have shown that IRC001 can trigger type I IFN signaling by engaging STING/TBK-1/IRF3-dependent pathways. To delve deeper into the spatial and molecular distinctions in mouse tumors (± IRC001), we initiated a preliminary study utilizing 10x Genomics/Visium to examine the spatial variations between these tumor types. Significantly, our spatial transcriptomic analysis revealed consistent immune-excluded and immune-enriched characteristics compared to traditional RNA sequencing methods. We conducted an analysis of TCGA datasets (The Cancer Genome Atlas) and observed that elevated IRC001 expression is associated with improved prognosis in SKCM (Skin Cutaneous Melanoma). Furthermore, our bioinformatics analysis revealed that melanoma patients exhibiting heightened IRC001 expression displayed positive responses to immune checkpoint blockade therapies. Therefore, we believe that our experimental tumor model can provide vital insights into the cold tumor microenvironment, shaping future therapeutic strategies, and pinpointing molecular candidates that can assist in selecting patients for successful immunotherapy. Citation Format: Yi-Ting Liao, Li-Mei Chen, Wen-Jye Lin. Establishing a screening platform to identify key signaling molecules regulating cold tumor formation through immune evasion and exclusion [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B038.

Comparison of retinol binding protein 1 with cone specific G-protein as putative effector molecules in cryptochrome signalling.

Vision and magnetoreception in navigating songbirds are strongly connected as recent findings link a light dependent radical-pair mechanism in cryptochrome proteins to signalling pathways in cone photoreceptor cells. A previous yeast-two-hybrid screening approach identified six putative candidate proteins showing binding to cryptochrome type 4a. So far, only the interaction of the cone specific G-protein transducin α-subunit was investigated in more detail. In the present study, we compare the binding features of the G-protein α-subunit with those of another candidate from the yeast-two-hybrid screen, cellular retinol binding protein. Purified recombinant European robin retinol binding protein bound retinol with high affinity, displaying an EC50 of less than 5nM, thereby demonstrating its functional state. We applied surface plasmon resonance and a Förster resonance transfer analysis to test for interactions between retinol binding protein and cryptochrome 4a. In the absence of retinol, we observed no robust binding events, which contrasts the strong interaction we observed between cryptochrome 4a and the G-protein α-subunit. We conclude that retinol binding protein is unlikely to be involved in the primary magnetosensory signalling cascade.

Integrated proteome and metabolome analysis of the penultimate internodes revealing remobilization efficiency in contrasting barley genotypes under water stress.

The remobilization of stored assimilates from stems to seeds plays a pivotal role in augmenting barley yield, particularly under water stress conditions. This study examines the molecular mechanisms underlying stem reserve utilization by conducting a comparative analysis of the proteome and metabolome across three barley contrasting genotypes: Yousef, Morocco, and PBYT17. Evaluations were performed at 21 and 28 days after anthesis (DAA) under both water stress and control conditions. The results indicate that the Yousef genotype exhibits superior remobilization of stem reserves, thereby demonstrating its potential to thrive even in adverse environmental conditions. Utilizing advanced quantitative proteomics and targeted metabolomics, this investigation identified a significant number of metabolites and proteins exhibiting differential accumulation across the genotypes. Specifically, 17 metabolites and 1580 proteins were catalogued, highlighting the intricate biochemical responses to water stress. Noteworthy enzymes such as sucrose synthase, inositol monophosphatase 3, and galactokinase were found to be closely associated with remobilization efficiency. In the drought-tolerant genotype, these enzymes maintained stable levels, in stark contrast to the decline observed in the susceptible genotype. This stability is crucial for promoting seed development through ascorbic acid synthesis and for mitigating oxidative stress, which is exacerbated by drought conditions. The elevated levels of certain metabolites, including glucose 6-phosphate, and UDP-glucose, in the drought-tolerant genotype suggest a robust mechanism for maintaining signalling molecules for carbon availability, which is then instrumental in regulating plant growth and seed size development. The findings from this study strongly imply that the drought-tolerant genotype, through enhanced antioxidant capacity, can effectively produce energy-rich storage compounds, thereby optimizing carbon allocation under water stress. Such insights are invaluable for future breeding strategies aimed at improving barley resilience in the face of climate variability.

Regulatory Effects of Copper on Ghrelin Secretion in Rat Fundic Glands.

Copper (Cu) is an effective additive in feed for promoting growth. Growth dan axis comprising growth hormone (GH), somatostatin (SS) and GH-releasing hormone (GHRH), with ghrelin regulating their release. The growth-promoting effects of Cu are closely related to ghrelin, but the specific mechanism behind the relationship remains unknown. We investigated the adjustment of ghrelin synthesis and secretion by Cu. Sprague-Dawley rats were fed basal diets with an addition of 0, 120 or 240 mg/kg Cu sulfate for 28 day to establish a growth-promoting model. Signalling molecules relevant to ghrelin synthesis and secretion were detected and mechanistically explored using enzyme-linked immunosorbent assay, quantitative reverse-transcription polymerase chain reaction and Western blot analysis. The 120 mg/kg supplement improved growth performance; significantly increased the serum levels of ghrelin, ghrelin O-acyltransferase (GOAT), acylated ghrelin (AG), GH, and reactive oxygen species (ROS) and decreased those of SS; significantly increased the mRNA and protein expression of ghrelin, GOAT, ghrelin receptor (GHS-R1α), and activator protein 1 (AP-1); increased the phosphorylation ratio of JNK and p38 MAPK; and inhibited the mRNA and protein expression of SS and SS receptor subtype 2 (SSTR2) in gastric fundic gland tissues. Thus, Cu may affect gastric ghrelin synthesis at the transcriptional level by activating the JNK/p38 MAPK pathway through increased ROS levels and regulating the activation of the downstream redox-sensitive transcription factor AP-1. SS plays a crucial determinant role in ghrelin regulation via intragastric Cu. Cu promotes GOAT activity and ghrelin secretion by inhibiting SS secretion, affecting AG levels, and promoting ghrelin acylation through ghrelin/GOAT/GHS-R1α system, modulating ghrelin secretion.

Enhanced activity of mixed-culture electroactive biofilms and sulfamethoxazole removal efficiency by adding N-acyl-homoserine lactones in bio-electrochemical system

ABSTRACT The addition of exogenous quorum sensing signaling molecules significantly enhanced the degradation efficiency of antibiotics, such as chloramphenicol in bio-electrochemical systems (BESs). However, the effects and mechanisms by which AHLs addition in BES facilitated the removal of sulfamethoxazole (SMX) remained inadequately explored. This study systematically compared the electrochemical performance and SMX removal efficiency in BES under two conditions: with and without the addition of N-acyl-homoserine lactones (AHLs) signaling molecules. In comparison to the control group, the AHL-treated group exhibited an increase in maximum output voltage from 340 to 489.67 mV, alongside a notable enhancement in SMX removal efficiency over 120 h ranging from 14.65% to 15.76%. Analyses of the live and dead cells and extracellular polymeric substances (EPS) composition revealed that following AHLs addition, both the ratio of live to dead cells and protein content within EPS increased by 12.66% and 74.37%, respectively. Furthermore, microbial community structure analysis indicated that after AHLs supplementation, there was a marked increase in the abundance of electroactive microorganisms as well as antibiotic-degrading and nitrogen-removing bacteria. Notably, Klebsiella – characterised by its electroactivity along with antibiotic degradation and nitrogen removal capabilities – exhibited a relative abundance reaching 56.84% in AHL, reflecting an increase of 28.31% compared to Blank; additionally, electroactive bacteria Dysgonomonas showed a relative abundance rise of 2.49%. Collectively, these findings suggested that enhancements in SMX removal efficiency upon AHLs addition were primarily driven by improvements in electrochemical performance coupled with alterations in microbial community structure.

SPOP-mediated RIPK3 destabilization desensitizes LPS/sMAC/zVAD-induced necroptotic cell death.

RIPK1/RIPK3-MLKL signaling molecules are fundamental in initiating necroptotic cell death, but their roles in the development of colon cancer are unclear. This study reports that RIPK3 interacted with SPOP, a component of the E3 ligase within the Cul3 complex. This interaction leads to K48-linked ubiquitination and subsequent proteasomal degradation of RIPK3. Two distinct degron motifs, PETST and SPTST, were identified within the linker domain of RIPK3 for SPOP. RIPK3 phosphorylations at Thr403 by PIM2 and at Thr412/Ser413 by ERK2 are essential to facilitate its interaction with SPOP. Computational docking studies and immunoprecipitation analyses showed that these PIM2 and ERK2 phosphorylations bolster the stability of the RIPK3-SPOP interaction. In particular, mutations of RIPK3 at the degron motifs extended the half-life of RIPK3 by preventing its phosphorylation and subsequent ubiquitination. The deletion of SPOP, which led to increased stability of the RIPK3 protein, intensified LPS/sMAC/zVAD-induced necroptotic cell death in colon cancer cells. These findings underscore the critical role of the SPOP-mediated RIPK3 stability regulation pathway in controlling necroptotic cell death.

Ulinastatin attenuates renal fibrosis by regulating AMPK/HIF-1α signaling pathway-mediated glycolysis.

Renal fibrosis is a common outcome of chronic kidney diseases and glycolysis drives the development of renal fibrosis in damaged kidneys. Ulinastatin (UTI) is a broad-spectrum protease inhibitor with anti-inflammatory and antioxidant properties with anti-fibrosis effects. In this study, we aimed to verify whether UTI could exert anti-renal fibrosis effects by inhibiting glycolysis and explored the potential mechanisms. Renal fibrosis was induced in mice via unilateral ureteral obstruction (UUO). Transforming growth factor-β1 stimulates human kidney proximal tubular epithelial cells to undergo fibrotic changes. Histopathological staining was used to observe the pathological changes in the kidneys. The levels of fibrosis biomarkers, glycolytic enzymes, and key signaling molecules were determined using gene and protein assays. Cellular energy metabolism was measured using Seahorse XF24 analyzer. Modulated the activity of adenylate-activated protein kinase (AMPK) and hypoxia-inducible factor-1α (HIF-1α) to confirm that AMPK can regulate HIF-1α-mediated glycolysis. Furthermore, UTI and AMPK knockdown were combined to verify whether UTI could attenuate glycolysis via the AMPK pathway. UTI pretreatment improved UUO-induced renal injury and fibrosis. The expression of fibrosis biomarkers and glycolytic enzymes was reduced by UTI at both mRNA and protein levels. UTI treatment decreased the rate of glycolysis and the production of glycolytic intermediates in fibrotic cells and tissues. Furthermore, AMPK can regulate HIF-1α-mediated glycolysis in renal tubular epithelial cells. Finally, the attenuation of glycolysis by UTI was related to AMPK/HIF-1α pathway, and this effect was inhibited by knockdown AMPK. UTI can effectively alleviate renal fibrosis, which may be partly attributed to the reduction of glycolysis by regulating AMPK/HIF-1α pathway.

A signaling pathway map of plasminogen activator inhibitor-1 (PAI-1/SERPINE-1): a review of an innovative frontier in molecular aging and cellular senescence.

Plasminogen activator inhibitor-1 (PAI-1) is a vital regulator of the fibrinolytic mechanism and has beenintricately involved in various physiological and clinical processes, including cancer, thrombosis, and wound healing. The PAI-1 signaling pathway is multifaceted, encompassing numerous signaling molecules and nodes. Recent studies haverevealeda novel contribution of PAI-1 during cellular senescence. This review introduces a pathway resource detailing the signaling network events mediated by PAI-1. The literature curated on the PAI-1 system was manually compiled from variouspublished studies,our analysis presents a signaling pathway network of PAI-1, which includes various events like enzyme catalysis, molecular association, gene regulation, protein expression, and protein translocation. This signaling network aims to provide a detailed analysis of the existing understanding of the PAI-1 signaling pathway in the context of cellular senescence across various research models. By developing this pathway, we aspire to deepen our understanding of aging and senescence research, ultimately contributing to the pursuit of effective therapeutic approaches for these complex chronic diseases.

"Elucidating the immunomodulatory role of endocannabinoids in intervertebral disc degeneration".

The endocannabinoid system (ECS) has been well-established to play a crucial role in the regulation of several physiological processes as well as many inflammatory disease conditions. However, its role in intervertebral disc degeneration has been least explored. We aim to investigate the immunomodulatory role of endocannabinoids in regulating IVD health. The study population included 20 healthy volunteers (controls) and 40 patients with disc degeneration (disease group) (20 Modic and 20 Non Modic). 16S metagenome sequencing of the V3-V4 region was performed for the DNA extracted from NP tissue samples of both control and disease groups. Sequencing was carried out using the Novaseq 6000 platform using 250bp paired-end chemistry. A global metabolic profile was obtained using the uHPLC system coupled with Q Exactive Plus Hybrid Quadrupole-Orbitrap mass spectrometer. Our study revealed a higher prevalence of gram-negative bacteria, particularly opportunistic pathogens like Pseudomonas, in diseased discs (71-81%) compared to healthy controls (54%). Further investigation using metabolomics identified significant changes in the lipid profiles of diseased discs. We found that the signalling molecules of the ECS, 2-arachidonylglycerol (2-AG) and N-arachidonoylethanolamine (AEA), were significantly lower in diseased discs compared to controls (Log2FC -2.62 for 2-AG and -3.15 for AEA). Conversely, pro-inflammatory metabolites like LTA4, HPETE, HETE, and Prostaglandin G2 were elevated in diseased discs, with a Log2 fold increase greater than 2.5. The study reveals that the endocannabinoid metabolites (2-AG and AEA) of the ECS could be a significant molecule influencing susceptibility to infection and inflammation within the intervertebral discs, which could be a potential target for improving disc health. Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Mechanosensitive release of ATP in the urinary bladder mucosa.

The urinary bladder mucosa (urothelium and suburothelium/lamina propria) functions as a barrier between the content of the urine and the underlying bladder tissue. The bladder mucosa is also a mechanosensitive tissue that releases signaling molecules that affect functions of cells in the bladder wall interconnecting the mucosa with the detrusor muscle and the CNS. Adenosine 5'-triphosphate (ATP) is a primary mechanotransduction signal that is released from cells in the bladder mucosa in response to bladder wall distention and activates cell membrane-localized P2X and P2Y purine receptors on urothelial cells, sensory and efferent neurons, interstitial cells, and detrusor smooth muscle cells. The amounts of ATP at active receptor sites depend significantly on the amounts of extracellularly released ATP. Spontaneous and distention-induced release of ATP appear to be under differential control. This review is focused on mechanisms underlying urothelial release of ATP in response to mechanical stimulation. First, we present a brief overview of studies that report mechanosensitive ATP release in bladder cells or tissues. Then, we discuss experimental evidence for mechanosensitive release of urothelial ATP by vesicular and non-vesicular mechanisms and roles of the stretch-activated channels PIEZO channels, transient receptor potential vanilloid type 4, and pannexin 1. This is followed by brief discussion of possible involvement of calcium homeostasis modulator 1, acid-sensing channels, and connexins in the release of urothelial ATP. We conclude with brief discussion of limitations of current research and of needs for further studies to increase our understanding of mechanotransduction in the bladder wall and of purinergic regulation of bladder function.

Drought-tolerant wheat for enhancing global food security.

Wheat is among the most produced grain crops of the world and alone provides a fifth of the world's calories and protein. Wheat has played a key role in food security since the crop served as a Neolithic founder crop for the establishment of world agriculture. Projections showing a decline in global wheat yields in changing climates imply that food security targets could be jeopardized. Increased frequency and intensity of drought occurrence is evident in major wheat-producing regions worldwide, and notably, the wheat-producing area under drought is projected to swell globally by 60% by the end of the 21st century. Wheat yields are significantly reduced due to changes in plant morphological, physiological, biochemical, and molecular activities in response to drought stress. Advances in wheat genetics, multi-omics technologies and plant phenotyping have enhanced the understanding of crop responses to drought conditions. Research has elucidated key genomic regions, candidate genes, signalling molecules and associated networks that orchestrate tolerance mechanisms under drought stress. Robust and low-cost selection tools are now available in wheat for screening genetic variations for drought tolerance traits. New breeding techniques and selection tools open a unique opportunity to tailor future wheat crop with optimal trait combinations that help withstand extreme drought. Adoption of the new wheat varieties will increase crop diversity in rain-fed agriculture and ensure sustainable improvements in crop yields to safeguard the world's food security in drier environments.

Early-Life Stress Influences the Transcriptional Activation of Alpha-2A Adrenergic Receptor and Associated Protein Kinase A Signaling Molecules in the Frontal Cortex of Rats.

Early life is a highly sensitive period associated with profound changes in brain structure and function. Adverse experiences of early-life stress (ELS) are prominent risk factors for the precipitation of major depressive disorder (MDD). In recent years, dysfunction of the central noradrenergic (NA) system and subsequent deficits in norepinephrine (NE) signaling have gained increasing attention in the pathophysiology of MDD. However, the role of the α-2A adrenergic receptor and its downstream second messenger signaling system has not been investigated in connection to early-life stress-induced depression, limiting valuable insights into neurobiological mechanisms underlying this disorder. In this study, we used maternal separation (MS) as a rodent model of ELS to investigate whether ELS-induced depressive behavior is related to the α-2A adrenergic receptor and its associated second messenger signaling cascade. To do so, we studied expression levels of the α-2A adrenergic receptor (Adra2a), G alpha proteins (stimulatory subunit-Gαs [Gnas] and inhibitory subunit-Gαi [Gnai1 and Gnai2]), and downstream protein kinase A (PKA) catalytic [Prkarcα and Prkarcβ] and regulatory subunits [Prkar1α, Prkar1β, Prkar2α, and Prkar2β]) in the frontal cortex (FC) of MS rats. We found reduced sucrose preference in MS animals, along with reduced transcript levels of Adra2a, Gnai2, Prkar1β, and Prkarcβ. These findings suggest that ELS exposure may contribute to depression symptomatology via alterations in the expression of key genes involved in the NA system, highlighting potential mechanisms underlying ELS-induced depressive behavior.

Hydrogen peroxide mediates melatonin-induced chilling tolerance in cucumber seedlings.

MT mitigates chilling damage by enhancing antioxidant system and photosystem activities, and cold-responsive genes expression in cucumbers. H2O2 may act as a downstream signaling molecule in the MT-induced chilling tolerance. Melatonin (MT) and hydrogen peroxide (H2O2) are important endogenous signaling molecules that play multifaceted roles in plant responses to abiotic stress. However, the interactive mechanism by which MT and H2O2 regulate chilling tolerance remains unclear. Here we found that MT exhibited a positive regulatory effect on the chilling tolerance of cucumbers, with an optimum concentration of 100µM. MT markedly enhanced RBOH1 mRNA expression, activity and endogenous H2O2 accumulation in cucumber seedlings. However, 1.0mM H2O2 had no significant effect on mRNA levels of TDC and ASMT, the key genes for MT synthesis, and endogenous MT content. Both MT and H2O2 significantly decreased malondialdehyde (MDA), electrolyte leakage (EL) and chilling injury index (CI) by activating the antioxidant system, thereby alleviating chilling damage in cucumber seedlings. MT and H2O2 improved photosynthetic carbon assimilation, which was primarily attributed to an increase in activity, mRNA expression, and protein levels of RuBPCase and RCA. Meanwhile, MT and H2O2 induced the photoprotection for both PSII and PSI by enhancing the QA's electron transport capacity and elevating protein levels of the photosystems. Moreover, MT and H2O2 significantly upregulated the expression of cold response genes. MT-induced chilling tolerance was attenuated by N', N'-dimethylthiourea (DMTU), a H2O2 specific scavenger. Whereas, the MT synthesis inhibitor (p-chlorophenylalanine, p-CPA) did not influence H2O2-induced chilling tolerance. The positive regulation of MT on the antioxidant system, photosynthesis and cold response gene levels were significantly attenuated in RBOH1-RNAi plants compared with WT plants. These findings suggest that H2O2 may functions as a downstream signaling molecule in MT-induced chilling tolerance in cucumber plants.

Copper homeostasis and neurodegenerative diseases

Copper, one of the most prolific transition metals in the body, required for normal brain physiological activity and allows various functions to work normally through its range of concentrations. Copper homeostasis is meticulously maintained through a complex network of copper-dependent proteins, including copper transporters (CTR1 and CTR2), the two copper ion transporters the Cu -transporting ATPase 1 (ATP7A) and Cu-transporting beta (ATP7B), and the three copper chaperones ATOX1, CCS, and COX17. Disruptions in copper homeostasis can lead to either the deficiency or accumulation of copper in brain tissue. Emerging evidence suggests that abnormal copper metabolism or copper binding to various proteins, including ceruloplasmin and metallothionein, is involved in the pathogenesis of neurodegenerative disorders. However, the exact mechanisms underlying these processes are not known. Copper is a potent oxidant that increases reactive oxygen species production and promotes oxidative stress. Elevated reactive oxygen species levels may further compromise mitochondrial integrity and cause mitochondrial dysfunction. Reactive oxygen species serve as key signaling molecules in copper-induced neuroinflammation, with elevated levels activating several critical inflammatory pathways. Additionally, copper can bind aberrantly to several neuronal proteins, including alpha-synuclein, tau, superoxide dismutase 1, and huntingtin, thereby inducing neurotoxicity and ultimately cell death. This study focuses on the latest literature evaluating the role of copper in neurodegenerative diseases, with a particular focus on copper-containing metalloenzymes and copper-binding proteins in the regulation of copper homeostasis and their involvement in neurodegenerative disease pathogenesis. By synthesizing the current findings on the functions of copper in oxidative stress, neuroinflammation, mitochondrial dysfunction, and protein misfolding, we aim to elucidate the mechanisms by which copper contributes to a wide range of hereditary and neuronal disorders, such as Wilson's disease, Menkes' disease, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis. Potential clinically significant therapeutic targets, including superoxide dismutase 1, D-penicillamine (DPA), and 5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline (PBT2), along with their associated therapeutic agents, are further discussed. Ultimately, we collate evidence that copper homeostasis may function in the underlying etiology of several neurodegenerative diseases and offer novel insights into the potential prevention and treatment of these diseases based on copper homeostasis.

Exogenous Sodium Nitroprusside Exhibits Multiple Positive Roles in Alleviating Cadmium Toxicity in Tobacco (Nicotiana tabacum L.).

As a donor of the gaseous signaling molecule nitric oxide (NO), sodium nitroprusside (SNP) has been shown to play a positive role in enhancing plant resistance to abiotic stress. However, its role in alleviating cadmium (Cd) toxicity in tobacco (Nicotiana tabacum L.) is not fully understood. This study found that Cd stress significantly inhibited tobacco growth. At the same time, 150 μM SNP was the most effective concentration in alleviating Cd toxicity in seedlings, restoring three stress tolerance indicators-MDA, H2O2, and proline-to control levels. Exogenous SNP mitigated Cd-induced oxidative stress by promoting the accumulation of non-enzymatic antioxidants (total phenolics and flavonoids) and activating key antioxidant enzymes (SOD, CAT, POD, APX, and GR) along with their gene expression. SNP also facilitated Cd accumulation in the root cell wall and prevented Cd translocation from roots to shoots. Additionally, SNP altered Cd's subcellular distribution, promoting its sequestration in vacuoles and cell walls, which may be related to the NO-mediated upregulation of the metallothionein gene NtMT2F and the phytochelatin gene NtPCS2. The addition of SNP significantly increased the proportion of Cd in less toxic chemical forms, with the residual Cd fraction in the Cd + SNP group reaching 7.30%, higher than the 4.86% in the Cd-only group. Furthermore, exogenous SNP counteracted Cd's inhibition of nitrate reductase (NR) activity, promoting endogenous NO production. This study systematically reveals the positive roles of exogenous SNP in mitigating Cd toxicity in tobacco, offering valuable insights for producing low-Cd tobacco.

Porcine decellularized nerve matrix hydrogel attenuates neuroinflammation after peripheral nerve injury by inhibiting the TLR4/MyD88/NF-κB axis

Peripheral nerve injury causes severe neuroinflammation and has become a global medical challenge. Previous research has demonstrated that porcine decellularized nerve matrix hydrogel exhibits excellent biological properties and tissue specificity, highlighting its potential as a biomedical material for the repair of severe peripheral nerve injury; however, its role in modulating neuroinflammation post–peripheral nerve injury remains unknown. Here, we aimed to characterize the anti-inflammatory properties of porcine decellularized nerve matrix hydrogel and their underlying molecular mechanisms. Using peripheral nerve injury model rats treated with porcine decellularized nerve matrix hydrogel, we evaluated structural and functional recovery, macrophage phenotype alteration, specific cytokine expression, and changes in related signaling molecules in vivo. Similar parameters were evaluated in vitro using monocyte/macrophage cell lines stimulated with lipopolysaccharide and cultured on porcine decellularized nerve matrix hydrogel–coated plates in complete medium. These comprehensive analyses revealed that porcine decellularized nerve matrix hydrogel attenuated the activation of excessive inflammation at the early stage of peripheral nerve injury and increased the proportion of the M2 subtype in monocytes/macrophages. Additionally, porcine decellularized nerve matrix hydrogel negatively regulated the Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB axis both in vivo and in vitro. Our findings suggest that the efficacious anti-inflammatory properties of porcine decellularized nerve matrix hydrogel induce M2 macrophage polarization via suppression of the Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-?B pathway, providing new insights into the therapeutic mechanism of porcine decellularized nerve matrix hydrogel in peripheral nerve injury.

The Effect of Prenatal Stress on the Level of NO-Metabolites in the Central Nervous System

Nitric oxide performs a number of essential functions in the central nervous system. This neurotransmitter regulates apoptotic processes, differentiation and proliferation of neurons, synaptic activity, plasticity. Prenatal stress may be a factor affecting the NO level in different parts of the central nervous system (CNS). The aim of the work was to study the level of NO metabolites in phylogenetically different parts of the central nervous system in prenatally stressed mature male and female rats, depending on the stage of the estrous cycle. Pregnant female rats (n = 12) were subjected to stress from the 16th to the 19th days of pregnancy for 3 hours in the morning. The NO level was assessed in adult (4-month-old) offspring of both sexes. In males, there was a decrease in the level of NO metabolites in the cerebellum and hypothalamus and an increase in the spinal cord. The level of NO metabolites within the studied parts of the CNS of females in the control was higher, after undergoing prenatal stress it changed less compared to males: significant changes were noted in the spinal cord regardless of the estrus cycle stage and in the cerebellum at the stage of estrus. Thus, regardless of gender, the phylogenetically younger structure, the cerebral cortex, turned out to be the most resistant to prenatal stress; the most pronounced changes were noted in the phylogenetically ancient part of the CNS, the spinal cord. Given the importance of NO in the CNS as a key signaling molecule, any changes in its level under the influence of prenatal stress can both have a significant adaptive value and have negative consequences for the functional state of the tissue.

Abstract A059: Serum EphA2 proteolytic fragment is a potent biomarker for diagnosing a very early stage of ductal pancreatic carcinoma

Abstract Erythropoietin-producing hepatocellular receptor A2 (EphA2) is a receptor tyrosine kinase, and its expression increases with malignant progression of cancer. Therefore, EphA2 is believed to be a candidate for molecular cancer therapy and many candidate drugs targeting EphA2 have been developed, but their effects are limited. The reason is its complex signaling functions. In fact, EphA2 has a tumor suppressor function regulated by the stimulation of the Ephrin-A ligand, while in the absence of ligand stimulation, it has a prooncogenic function in collaboration with EGFR and its downstream signaling molecules. The opposite functions of EphA2 make it difficult to develop it as a cancer drug target. We have previously demonstrated that a type-1 matrix membrane metalloprotease (MT1-MMP) at cancer cell surface interacted with EphA2 and selectively cleaved its N-terminal ligand binding site, converting it into a prooncogenic signaling transmitter (Koshikawa N et al., Cancer Research, 2015). We also found that the N- terminal fragment of EphA2 (termed EphA2-NF) released by MT1-MMP cleavage increased in sera from patients with gastric cancer and ductal pancreatic carcinoma (PDC) (Koshikawa N et al., Cell Death & Disease, 2017). In this study, we compare the expression of EphA2-NF in serum from a healthy donor (HD: 150 cases), patients with chronic pancreatic disease (87 cases), and PDC (578 cases) by automated chemiluminescence immunoassay with a specific EphA2-NF monoclonal antibody. As a result, PDC cases, including stage I/II PDC, show significantly higher levels of EphA2-NF than HD (Sato et al. Cancer Research Communications, 2023). Furthermore, PDC occurred in the intraductal papillary mucinous neoplasm (IPMN) cases with high levels of EphA2-NF during follow-up observation. Therefore, to verify that the EphA2 proteolytic cleavage occurred in the PDC onset, we analyzed 50 surgical resected tissues from patients with PDC and IPMN to detect the N and C-terminal regions of EphA2 by immunohistochemical staining. Interestingly, PDC, including early stage PDC cases, lacked the N-terminus of EphA2. Furthermore, the deletion of N-terminus of EphA2 was observed in all tested cases pathologically diagnosed as intraductal papillary mucinous adenocarcinoma (IPMC) (Sato S et al., Cancer Research Communications, 2023). These results suggest that serum EphA2-NF has the potential to revolutionize the early detection and management of PDC, providing a valuable tool to diagnose the disease in very early stages when treatment results may be more favorable. Collaborators: Masatoshi Nakagawa, Eisaku Yoshida and Toru Yoshimura (Research and Development, Abbott Japan LLC) Citation Format: Naohiko Koshikawa, Shinya Sato, Kouki Nio, Takeshi Terashima, Makoto Ueno, Taro Yamashita. Serum EphA2 proteolytic fragment is a potent biomarker for diagnosing a very early stage of ductal pancreatic carcinoma [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A059.

Quorum sensing regulation of Psl polysaccharide production by Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a common opportunistic pathogen and a model organism for studying bacterial sociality. A social behavior of P. aeruginosa that is critical for its success as a pathogen is its ability to form protective biofilms. Many of P. aeruginosa's social phenotypes are regulated by quorum sensing-a type of cell-cell communication that allows bacteria to respond to population density. Although biofilm formation is known to be affected by quorum sensing, evidence for direct regulation of biofilm production by quorum regulators has remained elusive. In this work, we show that production of the major biofilm matrix polysaccharide Psl in P. aeruginosa PAO1 is regulated by the quorum regulators LasR and RhlR in stationary-phase cultures. Secretion of Psl into the culture medium requires LasR, RhlR, and the quorum signal molecules N-3-oxo-dodecanoyl-homoserine lactone and N-butanoyl homoserine lactone. Psl production in strains unable to synthesize the homoserine lactone signals can be restored by exogenous introduction of the signal molecules. We found that LasR and RhlR perform different roles in the regulation of Psl production: LasR acts at the promoter of the psl operon and activates transcription of the Psl biosynthetic genes, while RhlR activates translation of the psl transcripts. This work contributes to our understanding of the overlapping but distinct functions of the Las and Rhl quorum-sensing systems and implicates both in the direct regulation of biofilm matrix production.IMPORTANCEPseudomonas aeruginosa biofilms are responsible for many treatment-resistant infections in humans. Many cooperative behaviors in P. aeruginosa are controlled by quorum sensing, but evidence for a direct role of quorum sensing in the regulation of biofilm matrix production has been scant. In this work, we show that the Las and Rhl quorum-sensing systems have distinct roles in regulating production of the matrix polysaccharide Psl and that this regulation happens at the level of transcription (Las) and translation (Rhl) of the psl operon. These findings deepen our understanding of overlapping functions of Las and Rhl quorum sensing and the complex regulation of biofilm development in P. aeruginosa.