Signaling Molecules Research Articles

Exploring the role of Cdk5 on striatal synaptic plasticity in a 3-NP-induced model of early stages of Huntington’s disease

Impaired mitochondrial function has been associated with the onset of neurodegenerative diseases. Specifically, certain mitochondrial toxins, such as 3-nitropropionic acid (3-NP), initiate cellular changes within the striatum that closely resemble the pathology observed in Huntington’s disease (HD). Among the pivotal signaling molecules contributing to neurodegeneration, cyclin-dependent kinase 5 (Cdk5) stands out. In particular, Cdk5 has been implicated not only in cellular pathology but also in the modulation of synaptic plasticity. Given its widespread presence in the striatum, this study seeks to elucidate the potential role of Cdk5 in the induction of corticostriatal synaptic plasticity in murine striatal cells subjected to subchronic doses of 3-NP in vivo, aiming to mimic the early stages of HD. Immunostaining analyses revealed an increase in Cdk5 in tissues from animals treated with 3-NP, without a significant change in protein levels. Regarding striatal plasticity, long-term depression (LTD) was induced in both control and 3-NP cells when recorded in voltage clamp mode. The Cdk5 inhibitor roscovitine-reduced LTD in most cells. A minority subset of cells exhibited long-term potentiation (LTP) generation in the presence of roscovitine. The inhibitor of D1 receptors SCH23390 prevented LTP in three of nine cells, implying that MSN cells lacking D1/PKA activation were capable of LTP induction when Cdk5 was also blocked. Nevertheless, the co-administration of H89, a PKA inhibitor, along with roscovitine, prevented the generation of any type of plasticity in all recorded cells. These findings show the impact of 3-NP treatment on striatal plasticity and suggest that Cdk5 during early neurodegeneration may attenuate signaling pathways that lead neurons to increase their activity.

CAP superfamily proteins in human: a new target for cancer therapy.

The CAP (Cysteine-rich secretory protein, Antigen 5, and Pathogenesis-related protein 1) superfamily proteins (CAP proteins) are found in all kingdoms of life. The cysteine-rich secreted proteins are prevalent in human organs and tissues and serve as critical signaling molecules within cells, regulating a wide range of biochemical processes in the human body. Due to their involvement in numerous biological processes, CAP proteins have recently attracted significant attention, particularly in the context of tumorigenesis and cancer therapy. This review summarizes the expression patterns and roles of CAP proteins in various cancers. Additionally, it analyzes the mechanisms by which CAP proteins affect cancer cell proliferation and survival, regulate epithelial-mesenchymal transition, influence drug resistance, and regulate epigenetics. The review reveals that CAP proteins play distinct roles in various signaling pathways, such as the MAPK, PI3K-Akt, and p53 pathways, which are crucial for tumor progression. Furthermore, this review summarizes the tumor-inhibiting function of CAP proteins and their potential as cancer biomarkers. These findings suggest that CAP proteins represent a promising new target for innovative cancer diagnosis and treatment.

ABI3 regulates ABI1 function to control cell length in primary root elongation zone.

Post-embryonic primary root growth is effectively an interplay of several hormone signalling pathways. Here, we show that the ABA-responsive transcription factor ABI3 controls primary root growth through the regulation of JA signalling molecule JAZ1 along with ABA-responsive factor ABI1. In the absence of ABI3, the primary root elongation zone is shortened with significantly reduced cell length. Expression analyses and ChIP-based assays indicate that ABI3 negatively regulates JAZ1 expression by occupying its upstream regulatory sequence and enriching repressive histone modification mark H3K27 trimethylation, thereby occluding RNAPII occupancy. Previous studies have shown that JAZ1 interacts with ABI1, the protein phosphatase 2C, that works during ABA signalling. Our results indicate that in the absence of ABI3, when JAZ1 expression levels are high, the ABI1 protein shows increased stability, compared to when JAZ1 is absent, or ABI3 is overexpressed. Consequently, in the abi3-6 mutant, due to the higher stability of ABI1, reduced phosphorylation of plasma membrane H+-ATPase (AHA2) occurs. HPTS staining further indicated that abi3-6 root cell apoplasts show reduced protonation, compared to wild-type and ABI3 overexpressing seedlings. Such impeded proton extrusion negatively affects cell length in the primary root elongation zone. ABI3 therefore controls cell elongation in the primary root by affecting the ABI1-dependent protonation of root cell apoplasts. In summary, ABI3 controls the expression of JAZ1 and in turn modulates the function of ABI1 to regulate cell length in the elongation zone during primary root growth.

ROS as Signaling Molecules to Initiate the Process of Plant Acclimatization to Abiotic Stress.

During their life cycle, plants constantly respond to environmental changes. Abiotic stressors affect the photosynthetic and respiratory processes of plants. Reactive oxygen species (ROS) are produced during aerobic metabolism and play an important role as regulatory mediators in signaling processes, activating the plant's protective response to abiotic stress and restoring "oxidation-reduction homeostasis". Cells develop normally if the rates of ROS production and the ability to neutralize them are balanced. To implement oxidation-reduction signaling, this balance must be disrupted either by an increase in ROS concentration or a decrease in the activity of one or more antioxidant systems. Under abiotic stress, plants accumulate excessive amounts of ROS, and if the ROS content exceeds the threshold amount dangerous for living organisms, it can lead to damage to all major cellular components. Adaptive resistance of plants to abiotic stressors depends on a set of mechanisms of adaptation to them. The accumulation of ROS in the cell depends on the type of abiotic stress, the strength of its impact on the plant, the duration of its impact, and the recovery period. The aim of this review is to provide a general understanding of the processes occurring during ROS homeostasis in plants, oxidation-reduction processes in cellular compartments in response to abiotic stress, and the participation of ROS in signaling processes activating adaptation processes to abiotic stress.

Bone morphogenetic protein 4 induces hematopoietic stem cell development from murine hemogenic endothelial cells in culture.

Hematopoietic stem cells (HSCs) develop from hemogenic endothelial cells (HECs) during mouse embryogenesis. Understanding the signaling molecules required for HSC development is crucial for the invitro derivation of HSCs. We previously induced HSCs from embryonic HECs, isolated at embryonic day 10.5 (E10.5), in serum-free culture conditions with stem cell factor, thrombopoietin, and an endothelial feeder layer. Here, we aimed to elucidate signal requirements for inducing HSCs from earlier-stage HECs. Single-cell RNA sequencing (RNA-seq) analysis detected bone morphogenetic protein (BMP) signaling activation in E9.5 HECs. Adding BMP4 to the culture conditions led to the induction of HSCs from E9.5 HECs. Furthermore, isolating BMP4 receptor-expressing HECs from E9.5 embryos enriched progenitors with HSC-forming ability. This study identified BMP4 as an essential factor promoting the differentiation of early HECs into HSCs, opening up new possibilities for the invitro derivation of HSCs.

Pathogenetic relationship of microbiome and metabolic disorders on the background of hypertension and gout: Potential targets of pharmacotherapy

Cardiometabolic diseases are one of the urgent problems of modern medicine. Currently, much attention is being paid to the study of the common pathogenesis of diabetes mellitus, gout and hypertension. One of the pharmacological targets is the correction of the intestinal microbiome and dysbiosis, as an integral link in the development of systemic inflammation and endotoxinemia, leading to the development of these pathologies. The article presents the results of scientific research devoted to the study of the effect of the intestinal microbiome on the development of cardiometabolic diseases. The main goal of the research is to find a rational pharmacological therapy of intestinal dysbiosis for the treatment of comorbid patients. It has been proved that, together with standard drug therapy, taking into account the pathogenetic features of the development of cardiometabolic diseases, it is advisable to use drugs that affect the intestinal microbiome. The main classical approach is the use of probiotic drugs containing live bacteria. The use of probiotics in combination with probiotic drugs to support the growth of intestinal normoflora has become a promising direction. However, this approach requires a long period of correction of the microflora, which prompted the idea of using postbiotics – signaling molecules – products of the vital activity of the microflora for a more targeted and rapid effect on pathological processes, both in the intestine and on the organ system as a whole. This approach promotes the beginning of the development of synbiotics, a complex of microorganisms, growth factors and metabolites that made it possible to more effectively influence on dysbiotic processes in various pathologies, including dyslipidemia and cardiovascular diseases. Correction of intestinal barrier permeability disorders will help prevent the development of systemic complications associated with chronic pathologies. The article also presents the author’s scheme of the pathogenesis of cardiometabolic diseases, based on the study of current scientific research.

Polyamines: pleiotropic molecules regulating plant development and enhancing crop yield and quality.

Polyamines (PAs) are pleiotropic bioorganic molecules. Cellular PA contents are determined by a balance between PA synthesis and degradation. PAs have been extensively demonstrated to play vital roles in the modulation of plant developmental processes and adaptation to various environmental stresses. In this review, the latest advances on the diverse roles of PAs in a range of developmental processes, such as morphogenesis, organogenesis, growth and development, and fruit ripening, are summarized and discussed. Besides, the crosstalk between PAs and phytohormones or other signalling molecules, including H2O2 and NO, involved in these processes is dwelled on. In addition, the attempts made to improve the yield and quality of grain and vegetable crops through altering the PA catabolism are enumerated. Finally, several other vital questions that remain unanswered are proposed and discussed. These include the mechanisms underlying the cooperative regulation of developmental processes by PAs and their interplaying partners like phytohormones, H2O2 and NO; PA transport for maintaining homeostasis; and utilization of PA anabolism/catabolism for generating high-yield and good-quality crops. This review aims to gain new insights into the pleiotropic role of PAs in the modulation of plant growth and development, which provides an alternative approach for manipulating and engineering valuable crop varieties that can be used in the future.

Activation of receptor-independent fluid-phase pinocytosis promotes foamy monocyte formation in atherosclerotic mice

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death worldwide. Clinical and experimental data demonstrated that circulating monocytes internalize plasma lipoproteins and become lipid-laden foamy cells in hypercholesterolemic subjects. This study was designed to identify the endocytic mechanisms responsible for foamy monocyte formation, perform functional and transcriptomic analysis of foamy and non-foamy monocytes relevant to ASCVD, and characterize specific monocyte subsets isolated from the circulation of normocholesterolemic controls and hypercholesterolemic patients. We hypothesized that activation of fluid-phase macropinocytosis contributes to foamy monocyte formation in vitro and in hypercholesterolemic mice in vivo. High resolution scanning electron microscopy (SEM) and quantification of FITC/TRITC-dextran internalization demonstrated macropinocytosis stimulation in human (THP-1) and wild type murine monocytes. Stimulation of macropinocytosis induced foamy monocyte formation in the presence of unmodified, native LDL (nLDL) and oxidized LDL (ox-LDL) in vitro. Genetic blockade of macropinocytosis (LysMCre+Nhe1f/f) inhibited foamy monocyte formation in hypercholesterolemic mice in vivo and attenuated monocyte adhesion to atherosclerotic aortas ex vivo. Mechanistic studies identified NADPH oxidase 2 (Nox2)-derived superoxide (O2⋅−) as an important downstream signaling molecule stimulating macropinocytosis in monocytes. qRT-PCR identified CD36 as a major SR that increases in response to lipid loading in monocytes and deletion of CD36 (Cd36-/-) inhibited foamy monocyte formation in hypercholesterolemic mice. Bulk RNA-sequencing characterized transcriptional differences between non-foamy and foamy monocytes versus macrophages. Finally, flow cytometry analysis of CD14 and CD16 expression demonstrated a significant increase in intermediate monocytes in hypercholesterolemic patients compared to normocholesterolemic controls. These results provide novel insights into the mechanisms of foamy monocyte formation and potentially identify new therapeutic targets for the treatment of atherosclerosis.

Thio-ProTide strategy: a novel H2S donor–drug conjugate (DDC) alleviates hepatic injury via innate lysosomal targeting

Hydrogen sulfide (H2S) is a gas signaling molecule with versatile bioactivities; however, its exploitation for disease treatment appears challenging. This study describes the design and characterization of a novel type of H2S donor–drug conjugate (DDC) based on the thio-ProTide scaffold, an evolution of the ProTide strategy successfully used in drug discovery. The new H2S DDCs achieved hepatic co-delivery of H2S and an anti-fibrotic drug candidate named hydronidone, which synergistically attenuated liver injury and resulted in more sufficient intracellular drug exposure. The potent hepatoprotective effects were also attributed to the H2S-mediated multipronged intervention in lipid peroxidation both at the whole cellular and lysosomal levels. Lysosomal H2S accumulation and H2S DDC activation were facilitated by the hydrolysis through the specific lysosomal hydrolase, representing a distinct mechanism for lysosomal targeting independent of the classical basic moieties. These findings provided a novel pattern for the design of optimally therapeutic H2S DDC and organelle-targeting functional molecules.

Programmed DNA tile response system enabled accurate detection of ATP for clinical diagnosis

Adenosine triphosphate (ATP), as a crucial signaling molecule, is of high potential diagnosis value for multiple diseases. However, current technologies for ATP detection struggle to satisfy the harsh conditions required for biospecimen tests, existing several limitations for clinical practical application. In this study, the DNA tile response system was designed and constructed by integrating nucleic acid aptamer, hybrid chain reaction (HCR), and DNA tile self-assembly technology to achieve accurate detection of ATP in body fluid specimens. The DNA tile response system, possessing high-order structure characteristic, could remove HCR false-positive products and conquer the high noise background to enhance the detection sensitivity. Under the optimal reaction parameters, this system achieved the low limit of detection (LOD) of 189.23 nM over a wide linear range and splendid detection specificity faced with multiple interference terms. Furthermore, this system, possessing simple storage conditions, long-term detection stability, and superior anti-interference performance, was sufficient to satisfy the detection requirements for complicated biological specimens in multi-scenarios. Ultimately, the DNA tile response system showed excellent diagnostic efficiency that could easily distinguish urinary tract infection patients and healthy controls through ATP quantification, as well as hypertension patients and healthy ones. This system provides a high-potential rapid detection tool for early diagnosis and dynamic monitoring of urinary tract infections and hypertension, holding enormous potential for clinical translation due to the superiorities of simple operation, general applicability, and low instrument requirements.

Efficient nitrogen removal and stable operation of a dynamic membrane bioreactor (DMBR) for landfill leachate treatment

This study proposed a novel anoxic/4-stage aerobic/self-forming dynamic membrane bioreactor (DMBR) process for treating landfill leachate with low carbon-to-nitrogen ratio (COD/N). When the influent COD and NH4+-N were 3689 ± 425 and 1042 ± 96 mg/L, high removal efficiencies of 87 % for COD and 79 % for TN can be achieved. The mature dynamic membrane (DM) was rapidly established within 1 h, allowing one operational cycle to last over 20 days with the permeate turbidity below 5 NTU. The primary cause of biofouling was identified as the accumulation of small particles, proteins, polysaccharides, and inorganic components such as Ca2+ and Mg2+ in the DM layer. In addition, significant up-regulation of genes associated with quorum sensing signaling molecules (such as pac, trpE, dgcB), extracellular polymeric substances secretion (exoP, exoQ, algA), and biofilm formation (lasA) were observed in the DM layer, while some genus, like Thauera, Anaerolinea and Caldilinea were highly enriched in DM layer. These findings indicate that DMBR offers cost-effective and technically advantageous operations, making it a promising candidate for the treatment of high-strength landfill leachate.

The SlbHLH92 transcription factor enhances salt stress resilience by fine-tuning hydrogen sulfide biosynthesis in tomato

Ongoing soil salinization severely hampers plant growth and the sustainability of global crops production. Hydrogen sulfide (H2S), acting as a critical gaseous signaling molecule, plays a vital role in plant response to various environmental cues such as salt stress. Nonetheless, it is not well understood how the transcriptional network regulates H2S production in response to salt stress in tomato. Herein, we determine that the bHLH transcription factor SlbHLH92 functions as a transcriptional activator in tomato (Solanum lycopersicum L.), upregulating the expression of the L-CYSTEINE DESULFHYDRASE 1 (SlLCD1) gene involved in H2S biosynthesis, thereby enhancing the plants' tolerance to salt stress. When exposed to salt stress, overexpression of SlbHLH92 in tomato leads to enhanced salt tolerance compared to wild-type plants. In contrast, suppression of SlbHLH92 expression with RNAi silencing results in increased sensitivity to salt stress. Subsequent molecular and biochemical investigations confirm that the salt-induced SlbHLH92 upregulates the expression of SlLCD1, leading to an increase in H₂S levels, as well as other salt-responsive genes (SlCBL10 and SlVQ16), by directly binding to specific cis-elements in their promoter regions. Furthermore, the VQ-motif containing protein SlVQ16 physically interacts with SlbHLH92, thereby promoting an increase in its transcriptional activity. Taken together, our study reveals an emerging mechanism in which the SlbHLH92-SlVQ16-H2S signaling cascade contributes to enhancing salt tolerance in tomato, presenting potential genetic targets for breeding salt-tolerant tomato cultivars.

Melatonin application enhances salt stress-induced decreases in minerals, betalains, and phenolic acids in beet (Beta vulgaris L.) cultivars.

Melatonin is a potentially active signaling molecule and plays a crucial role in regulating the growth and development of plants under stress conditions, alleviating oxidative damage, enhancing antioxidant defence mechanisms and regulating ion homeostasis. This study examined the effects of exogenous melatonin application on leaf biomass, ion concentrations, betalains, phenolic acid and endogenous melatonin contents comparing red beet (Beta vulgaris L. 'Ruby Queen' and 'Scarlet Supreme') and white beet ('Rodeo' and 'Ansa') cultivars under increasing salinity levels of 50, 150, and 250 mM NaCl. Exogenous melatonin increased salinity-induced reductions in fresh and dry weights and osmotic potential in leaves. Na+ concentrations rose significantly with increasing salinity, but cultivar-specific decreases were observed in K+ and Ca2+ concentrations. Additionally, melatonin application improved betalain, betanin and neobetanin contents induced by salt stress. Furthermore, melatonin application caused salt stress and cultivar-specific changes in phenolic acid contents e.g., ferulic acid, sinapic acid, or m-coumaric acid, in soluble free, ester- and glycoside-conjugated and cell wall-bound forms. In addition, antioxidant enzyme activities and compound contents increased significantly in the beets and were subsequently lowered in a cultivar-specific manner by salt stress + melatonin treatment. The current findings indicate that exogenous melatonin improved plant stress tolerance suppressing reactive oxygen species levels, increasing the antioxidant enzyme activities and compound contents and reducing the levels of Na+, maintaining an ionic homeostasis in the selected red and white sugar beet cultivars. It appears that melatonin application may help improve cultivar-specific salt tolerance by enhancing ion homeostasis and betalain and phenolic acid production levels in beets.

The vital role of melatonin in the intestinal mucosal barrier integrity in chick

BackgroundThe intestinal tract, as the main place for nutrient digestion and absorption, is closely related to the health of livestock and poultry. Melatonin secreted by the pineal gland acts as an endocrine transport signaling molecule to regulate intestinal function. However, the effect on intestinal function after pineal removal is unclear. MethodsWe raised 24 chicks under 400-700 nm white light with or without pinealectomy for 21 days. We used electron microscopy, HE staining, PAS staining, immunohistochemistry, immunofluorescence staining and western blot to detect intestinal physical and to explore the effect of melatonin secreted by the pineal gland on the intestinal mucosa barrier function. ResultsThe results showed that after pineal gland removal, the structure of the intestinal villi is severely damaged. Moreover, there was an obviously down-regulation in the villi length, the number of goblet cells and and its secretion of MUC2 protein, the expression level of tight junction proteins (Occludin and ZO-1) and lysozyme secreted by paneth cells, number of PCNA positive cells and macrophage, and an up-regualtion in crypt depth and apoptosis level after pinealectomy, suggesting pinealectomy-mediated melatonin level decrease damaged the intestinal physical, chemical and immune barriers. ConclusionOur findings provide new theoretical support for the future use of melatonin in intestinal development and new ideas about the relationship between endocrine hormone and intestinal physiology.

Bile Acid Nanoparticles - An Emerging Approach for Site Specific Drug Targeting

Abstract: Bile acids, a group of steroidal acids present in the bile act as biological surfactants and ligands for bile acid transporter proteins for signalling molecules to perform various paracrine and endocrine functions. The enterohepatic circulation of bile acids can be exploited to develop at-tractive drug delivery approaches with improved targetability of facial amphiphiles and enhanced drug bioavailability by improving absorption and metabolic stability. The effectiveness, safety and targetability of nanoparticles conjugated with bile acids and salts have been discussed in the present review. Various modifications of bile acids promoting absorption and oral bioavailability of drugs for treatment of various disease conditions such as cancer, diabetes and psychosis has al-so been discussed. Additionally, neuroprotective effect of bile acids and salts has demonstrated utility in various neurodegenerative disorders. Nanoparticles based on bile acids and salts repre-sent an area of emergent interest due to their unique and modifiable properties for improving ef-fectiveness of drugs.

Role of local angiotensin II signaling in bladder function.

Angiotensin II signaling plays a crucial role in many different diseases. Although it has been known for several decades that local angiotensin II signaling molecules are present in the bladder, the understanding of their functions there is still limited, especially compared with other organ systems such as cardiovascular and respiratory systems. This article reviews current literature regarding local angiotensin II signaling in the urinary bladder. By reviewing several decades of literature, the field has provided strong evidence to support the presence of local angiotensin II signaling in the bladder, including the expression of angiotensin type 1 receptor and angiotensin type 2 receptor in both human and animal tissues. In addition, evidence suggests a functional role of angiotensin type 1 receptor in mediating bladder contractions. In bladder disease models, angiotensin II signaling can be upregulated, and angiotensin type 1 receptor activity is associated with increases in inflammation, fibrosis, and oxidative stress. We also address the gaps in knowledge that remain in understanding local angiotensin II signaling in the bladder, including limitations on clinical translatability. Although there is a strong foundation regarding the local presence and role of angiotensin II signaling in the bladder, further research is needed to support translational applications.

Role of the PGAM5-CypD mitochondrial pathway in methylglyoxal-induced bone loss in diabetic osteoporosis

Diabetic osteoporosis (DOP) is a skeletal complication with a high rate of disability. It results in a great burden to the patient's family and society. Methylglyoxal (MG) is a toxic by-product of the glycolytic process that occurs during diabetic conditions. It causes osteoblastic injury and con-tributes to the initiation and development of DOP. Disruption of mitochondrial homeostasis has been implicated as a cause of dysregulated osteo-blastogenesis, an essential step in bone formation. It is unclear whether mitochondrial dysfunction is involved in MG-induced osteoblast dysfunction. In this study, we showed that mitochondrial dysfunction contributes to MG-induced MC3T3-E1 cell apoptosis and impaired differentiation. A significant reduction of mitochondrial membrane potential (MMP) and ATP production occurred in MG-induced osteoblasts as well as increasing mitochondrial reactive oxygen species (mtROS) and intracellular Ca2+. Classical antioxidant N-Acetylcysteine (NAC) significantly attenuated mitochondrial dysfunction as well as osteoblast apoptosis and osteogenic differentiation damage induced by MG. More importantly, we found that activating phosphoglycerate mutase family member 5 (PGAM5) and cyclophilin D (CypD), which contributes to mitochondrial homeostasis, is involved in MG-induced osteoblast injury. Both PGAM5 and CypD knockdown effectively reversed osteoblast viability and function, whereas PGAM5 or CypD overexpression aggravated osteoblast injury caused by MG. Moreover, the result of co-transfection revealed that PGAM5 is an upstream signaling molecule of CypD. By constructing type I diabetes mouse models, we further found that the expression of PGAM5 and CypD were both increased in the femur along with a reduction of ATP and increased TUNEL-positive cells. These results, for the first time, suggest that MG-induced mitochondrial dysfunction induces osteoblast injury through the PGAM5-CypD pathway. This study provides insight into the prevention and treatment of DOP. Lay summaryThis study highlights the role of mitochondria in regulating osteoblast viability and function under conditions of diabetic osteoporosis (DOP). We found that the PGAM5-CypD mitochondrial pathway is activated following glycolytic by-product methylglyoxal (MG) treatment, which contributes to mitochondrial dysfunction and osteogenic dysfunction. This mechanism implicates mitochondria as a potential therapeutic target for osteoporosis.

T Regulatory Cell Subsets Do Not Restore for One Year After Acute COVID-19.

COVID-19, caused by SARS-CoV-2, triggers a complex immune response, with T regulatory cells (Tregs) playing a crucial role in maintaining immune homeostasis and preventing excessive inflammation. The current study investigates the function of T regulatory cells during COVID-19 infection and the subsequent recovery period, emphasizing their impact on immune regulation and inflammation control. We conducted a comprehensive analysis of Treg subpopulations in peripheral blood samples from COVID-19 patients at different stages: acute infection, early convalescence, and long-term recovery. Flow cytometry was employed to quantify Tregs including "naïve", central memory (CM), effector memory (EM), and terminally differentiated CD45RA+ effector cells (TEMRA). Additionally, the functional state of the Tregs was assessed by the expression of purinergic signaling molecules (CD39, CD73). Cytokine profiles were assessed through multiplex analysis. Our findings indicate a significant decrease in the number of Tregs during the acute phase of COVID-19, which correlates with heightened inflammatory markers and increased disease severity. Specifically, we found a decrease in the relative numbers of "naïve" and an increase in EM Tregs, as well as a decrease in the absolute numbers of "naïve" and CM Tregs. During the early convalescent period, the absolute counts of all Treg populations tended to increase, accompanied by a reduction in pro-inflammatory cytokines. Despite this, one year after recovery, the decreased subpopulations of regulatory T cells had not yet reached the levels observed in healthy donors. Finally, we observed the re-establishment of CD39 expression in all Treg subsets; however, there was no change in CD73 expression among Tregs. Understanding these immunological changes across different T regulatory subsets and adenosine signaling pathways offers important insights into the disease's pathogenesis and provides a broader view of immune system dynamics during recovery.

RIPK2 Is Crucial for the Microglial Inflammatory Response to Bacterial Muramyl Dipeptide but Not to Lipopolysaccharide.

Receptor-interacting serine/threonine protein kinase 2 (RIPK2) is a kinase that is essential in modulating innate and adaptive immune responses. As a downstream signaling molecule for nucleotide-binding oligomerization domain 1 (NOD1), NOD2, and Toll-like receptors (TLRs), it is implicated in the signaling triggered by recognition of microbe-associated molecular patterns by NOD1/2 and TLRs. Upon activation of these innate immune receptors, RIPK2 mediates the release of pro-inflammatory factors by activating mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB). However, whether RIPK2 is essential for downstream inflammatory signaling following the activation of NOD1/2, TLRs, or both remains controversial. In this study, we examined the role of RIPK2 in NOD2- and TLR4-dependent signaling cascades following stimulation of microglial cells with bacterial muramyl dipeptide (MDP), a NOD2 agonist, or lipopolysaccharide (LPS), a TLR4 agonist. We utilized a highly specific proteolysis targeting chimera (PROTAC) molecule, GSK3728857A, and found dramatic degradation of RIPK2 in a concentration- and time-dependent manner. Importantly, the PROTAC completely abolished MDP-induced increases in iNOS and COX-2 protein levels and pro-inflammatory gene transcription of Nos2, Ptgs2, Il-1β, Tnfα, Il6, Ccl2, and Mmp9. However, increases in iNOS and COX-2 proteins and pro-inflammatory gene transcription induced by the TLR4 agonist, LPS, were only slightly attenuated with the GSK3728857A pretreatment. Further findings revealed that the RIPK2 PROTAC completely blocked the phosphorylation and activation of p65 NF-κB and p38 MAPK induced by MDP, but it had no effects on the phosphorylation of these two mediators triggered by LPS. Collectively, our findings strongly suggest that RIPK2 plays an essential role in the inflammatory responses of microglia to bacterial MDP but not to LPS.

The Arabidopsis splicing factor PORCUPINE/SmE1 orchestrates temperature-dependent root development via auxin homeostasis maintenance.

Appropriate abiotic stress response is pivotal for plant survival and makes use of multiple signaling molecules and phytohormones to achieve specific and fast molecular adjustments. A multitude of studies has highlighted the role of alternative splicing in response to abiotic stress, including temperature, emphasizing the role of transcriptional regulation for stress response. Here we investigated the role of the core-splicing factor PORCUPINE (PCP) on temperature-dependent root development. We used marker lines and transcriptomic analyses to study the expression profiles of meristematic regulators and mitotic markers, and chemical treatments, as well as root hormone profiling to assess the effect of auxin signaling. The loss of PCP significantly alters RAM architecture in a temperature-dependent manner. Our results indicate that PCP modulates the expression of central meristematic regulators and is required to maintain appropriate levels of auxin in the RAM. We conclude that alternative pre-mRNA splicing is sensitive to moderate temperature fluctuations and contributes to root meristem maintenance, possibly through the regulation of phytohormone homeostasis and meristematic activity.