CaMKII, 'jack of all trades' in inflammation during cardiac ischemia/reperfusion injury

Phytochemical regulation of CaMKII in Alzheimer's disease: A review of molecular mechanisms and therapeutic potential

Alzheimer's disease (AD) is a common neurodegenerative disorder that leads to cognitive decline. CaMKII is a calcium-regulated kinase that is crucial for synaptic plasticity and memory. Phytochemicals with diverse origins, safety, and biological activity have attracted considerable attention in AD research. This systematic analysis of phytochemicals targeting CaMKII reveals their neuroprotective mechanisms against AD pathogenesis, highlighting CaMKII as a promising therapeutic target that warrants further preclinical investigation and drug development. We conducted a comprehensive review of the literature of phytochemicals that target CaMKII as a protective mechanism against AD. The search was conducted across multiple databases, including PubMed, Web of Science, China National Knowledge Internet, and Google Scholar, and covered the period from January 2000 to October 2024. A total of 301 articles were retrieved, of which 22 articles were included. The results showed that flavonoid, glycoside, terpene, and polyphenol analogs positively regulated CaMKII expression, whereas alkaloid analogs negatively regulated CaMKII expression. Different components of traditional Chinese medicine played different roles in CaMKII expression. Flavonoid compounds upregulated the expression of SYN, PSD-95, MAP2, and GluR1 to exert neuroprotective effects. Alkaloid and glycoside analogs inhibited Aβ deposition and tau hyperphosphorylation. Terpene analogs upregulated the SYN, PSD-95, NMDAR, BDNF, and PI3K/Akt signaling pathways to exert neuroprotection. Polyphenol analogs upregulated PSD-95, Munc18-1, SNAP25, SYN, and BDNF to exert neuroprotective effects. Emerging evidence demonstrates that select phytochemicals and traditional Chinese medicine compounds exert neuroprotective effects in AD by modulating CaMKII activity, thereby reducing Aβ accumulation, attenuating tau hyperphosphorylation, and enhancing synaptic plasticity, suggesting promising therapeutic potential.

Intracellular L-PGDS-Derived 15d-PGJ2 Inhibits CaMKII Through Lipoxidation to Alleviate Cardiac Ischemia/Reperfusion Injury

BACKGROUND

Myocardial ischemia/reperfusion (I/R) injury is a substantial challenge to the management of ischemic heart disease, the leading cause of mortality worldwide. Arachidonic acid (AA) is a prominent polyunsaturated fatty acid in the human body and plays an important role in various physiological and pathological conditions. AA metabolic enzymes determine AA levels; however, currently there is no comprehensive analysis of AA enzymes in cardiac I/R injury.

METHODS

The profiling of AA metabolic enzymes was analyzed with the RNA sequencing transcriptome data from the mouse heart tissues with I/R injury. Cultured neonatal and adult rat ventricular myocytes, human embryonic stem cell-derived cardiomyocytes, and in vivo mouse I/R models were used to confirm the role of L-PGDS (lipocalin-type prostaglandin D2 synthase)/15d-PGJ2 in I/R injury. A biotin-tagged 15d-PGJ2 analog combined with liquid chromatography-tandem mass spectrometry was used to identify the downstream signaling of L-PGDS/15d-PGJ2.

RESULTS

Based on the transcriptome data and experimental validations, L-PGDS, together with its downstream metabolite 15d-PGJ2, was downregulated in cardiac tissue with I/R injury. Functionally, L-PGDS overexpression mitigates myocardial I/R injury, whereas knockdown exacerbates the damage. Supplementation of 15d-PGJ2 alleviated I/R injury. Mechanistically, 15d-PGJ2 covalently bound to the Ca2+/CaMKII (calmodulin protein kinase II) and induced lipoxidation of its cysteine 495 (CaMKII-δ9) to dampen the formation of CaMKII oligomers and alleviate its overactivation, consequently ameliorating cardiomyocyte death and cardiac injury.

CONCLUSIONS

Our study uncovered L-PGDS/15d-PGJ2/CaMKII signaling as a new mechanism underlying I/R-induced cardiomyocyte death. This provides new mechanistic insights and therapeutic targets for myocardial I/R injury and subsequent heart failure. We also showed that lipoxidation is a new post-translational modification type for CaMKII, deepening our understanding of the regulation of its activity.

Ca2+/calmodulin-dependent protein kinase II regulates the inflammatory hDPSCs dentino-differentiation via BDNF/TrkB receptor signaling

CaMKII is a serine/threonine-specific protein kinase that plays a crucial role in normal and pathological conditions. However, limited information is available regarding the roles of CaMKII in dentinogenesis, particularly in an inflammatory context. Previously, we demonstrated the pivotal role of TrkB in inflammation-induced differentiation of hDPSCs into odontoblast-like cells. Here, we investigate the interaction between CaMKII and TrkB during hDPSCs odontogenic differentiation. hDPSCs were cultured and subjected to CaMKII knockdown using siRNA, followed by treatment with dentinogenic media. TNFα-stimulated cells were treated with CaMKII- inhibitor, -protein, or TrkB antagonist, CTX-B. Immunocytochemistry and ARS were used to visualize targeted proteins and calcium deposits. Real-time PCR detected expression levels of odontogenic and mineralization markers such as DSPP and DMP-1. Our data indicate that CaMKII inhibition enhances TrkB protein levels and promotes TNFα-induced transcriptional activation of genes associated with odontogenic differentiation. CaMKII knockdown via siRNA and pharmacological inhibition elevated DSPP and DMP-1 protein levels, whereas CaMKII overexpression suppressed their expression. Notably, treatment with TNF-α and a CaMKII inhibitor upregulated DSPP and DMP-1 expression, while co-treatment with CTX-B abolished this effect. Similarly, mRNA expression of DSPP and DMP-1 was reduced at day 10. Mineralization activity exhibited a similar pattern to the expression of these markers. Our findings unveil a novel mechanism underlying the role of CaMKII via TrkB in dentinogenesis, which is vital for the success of hDPSCs engineering strategies.

PRMT1 alleviates isoprenaline-induced myocardial hypertrophy by methylating SRSF1

Myocardial hypertrophy (MH) is an important factor contributing to severe cardiovascular disease. Previous studies have demonstrated that specific deletion of the protein arginine methyltransferase 1 (PRMT1) leads to MH, but the exact mechanism remains unclear. Serine/arginine-rich splicing factor 1 (SRSF1) affects the development and progression of cardiovascular disease by selectively splicing downstream signaling proteins. The present study is designed to determine whether PRMT1 is involved in MH by regulating SRSF1 and, if so, to explore the underlying mechanisms. Adult male mice and H9C2 cardiomyocytes are treated with isoprenaline (ISO) to establish MH models. The expression levels of PRMT1 are significantly decreased in the ISO-induced MH models, and inhibiting PRMT1 worsens MH, whereas overexpression of PRMT1 ameliorates MH. SRSF1 serves as the downstream target of PRMT1, and its expression is markedly elevated in MH. Moreover, SRSF1 increases the mRNA expressions of CaMKIIδ A and CaMKIIδ B, decreases the mRNA expression of CaMKIIδ C by altering the selective splicing of CaMKIIδ, and further participates in MH. In addition, there is an interaction between PRMT1 and SRSF1, whereby PRMT1 reduces the phosphorylation level of SRSF1 via methylation, thus further altering its functional activity and eventually improving MH. Our present study demonstrates that PRMT1 relieves MH by methylating SRSF1, which is expected to provide a new theoretical basis for the pathogenic mechanism of MH and potential drug targets for reducing MH and associated cardiovascular disease.

Oxidative Stress and Inflammation in Myocardial Ischemia-Reperfusion Injury: Protective Effects of Plant-Derived Natural Active Compounds

Acute myocardial infarction (AMI) remains a leading cause of death among patients with cardiovascular diseases. Percutaneous coronary intervention (PCI) has been the preferred clinical treatment for AMI due to its safety and efficiency. However, research indicates that the rapid restoration of myocardial oxygen supply following PCI can lead to secondary myocardial injury, termed myocardial ischemia-reperfusion injury (MIRI), posing a grave threat to patient survival. Despite ongoing efforts, the mechanisms underlying MIRI are not yet fully elucidated. Among them, oxidative stress and inflammation stand out as critical pathophysiological mechanisms, playing significant roles in MIRI. Natural compounds have shown strong clinical therapeutic potential due to their high efficacy, availability, and low side effects. Many current studies indicate that natural compounds can mitigate MIRI by reducing oxidative stress and inflammatory responses. Therefore, this paper reviews the mechanisms of oxidative stress and inflammation during MIRI and the role of natural compounds in intervening in these processes, aiming to provide a basis and reference for future research and development of drugs for treating MIRI.

Multi-faceted potential of sophoridine compound's anti-arrhythmic and antioxidant effects through ROS/CaMKII pathway

Cardiac arrhythmias remain a significant cause of mortality and morbidity, for novel antiarrhythmic therapies. This study states that the first report of sophoridine (SPN), a quinolizidine alkaloid derived from traditional Chinese herbs, shows promise as a potential candidate due to its anti-arrhythmic and antioxidant properties. The study found that cell viability in H9C2 rat cardiomyocytes remained stable even when treated with SPN at a higher dosage of 100 μg/ml. This phenomenon was accompanied by increases in mitochondria-derived reactive oxygen species (ROS) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling, at 50 and 100 μg/ml. Glucose fluctuations regulate ventricular arrhythmias caused by SPN by activating the ROS/CaMKII pathway. Experimental models using zebrafish provided additional evidence supporting the regulatory effects of SPN on heart rate. In addition, the administration of SPN resulted in substantial deregulation of crucial genes involved in heart development (nppa, nppb, tnnt2a) at the transcriptional level in zebrafish. These findings provide insight into the various pharmacological properties of SPN and this opens up new possibilities for anti-arrhythmic treatment strategies.

CaMK II in Cardiovascular Diseases, Especially CaMK II-δ: Friends or Enemies

Cardiovascular diseases (CVDs) tend to affect the young population and are associated with a significant economic burden and psychological distress to the society and families. The physiological and pathological processes underlying CVDs are complex. Ca2+/calmodulin-dependent kinase II (CaMK II), a protein kinase, has multiple biological functions. It participates in multiple pathological processes and plays a central role in the development of CVDs. Based on this, this paper analyzes the structural characteristics and distribution of CaMK II, the mechanism of action of CaMK II, and the relationship between CaMK II and CVDs, including ion channels, ischemia-reperfusion injury, arrhythmias, myocardial hypertrophy, cardiotoxicity, hypertension, and dilated cardiomyopathy. Given the different regulatory mechanisms of different isoforms of CaMK II, the clinical use of specific targeted inhibitors or novel compounds should be evaluated in future research to provide new directions.

The CaMK Family Differentially Promotes Necroptosis and Mouse Cardiac Graft Injury and Rejection

Organ transplantation is associated with various forms of programmed cell death which can accelerate transplant injury and rejection. Targeting cell death in donor organs may represent a novel strategy for preventing allograft injury. We have previously demonstrated that necroptosis plays a key role in promoting transplant injury. Recently, we have found that mitochondria function is linked to necroptosis. However, it remains unknown how necroptosis signaling pathways regulate mitochondrial function during necroptosis. In this study, we investigated the receptor-interacting protein kinase 3 (RIPK3) mediated mitochondrial dysfunction and necroptosis. We demonstrate that the calmodulin-dependent protein kinase (CaMK) family members CaMK1, 2, and 4 form a complex with RIPK3 in mouse cardiac endothelial cells, to promote trans-phosphorylation during necroptosis. CaMK1 and 4 directly activated the dynamin-related protein-1 (Drp1), while CaMK2 indirectly activated Drp1 via the phosphoglycerate mutase 5 (PGAM5). The inhibition of CaMKs restored mitochondrial function and effectively prevented endothelial cell death. CaMKs inhibition inhibited activation of CaMKs and Drp1, and cell death and heart tissue injury (n = 6/group, p < 0.01) in a murine model of cardiac transplantation. Importantly, the inhibition of CaMKs greatly prolonged heart graft survival (n = 8/group, p < 0.01). In conclusion, CaMK family members orchestrate cell death in two different pathways and may be potential therapeutic targets in preventing cell death and transplant injury.

Stem Cell Therapy against Ischemic Heart Disease

Ischemic heart disease, which is one of the top killers worldwide, encompasses a series of heart problems stemming from a compromised coronary blood supply to the myocardium. The severity of the disease ranges from an unstable manifestation of ischemic symptoms, such as unstable angina, to myocardial death, that is, the immediate life-threatening condition of myocardial infarction. Even though patients may survive myocardial infarction, the resulting ischemia-reperfusion injury triggers a cascade of inflammatory reactions and oxidative stress that poses a significant threat to myocardial function following successful revascularization. Moreover, despite evidence suggesting the presence of cardiac stem cells, the fact that cardiomyocytes are terminally differentiated and cannot significantly regenerate after injury accounts for the subsequent progression to ischemic cardiomyopathy and ischemic heart failure, despite the current advancements in cardiac medicine. In the last two decades, researchers have realized the possibility of utilizing stem cell plasticity for therapeutic purposes. Indeed, stem cells of different origin, such as bone-marrow- and adipose-derived mesenchymal stem cells, circulation-derived progenitor cells, and induced pluripotent stem cells, have all been shown to play therapeutic roles in ischemic heart disease. In addition, the discovery of stem-cell-associated paracrine effects has triggered intense investigations into the actions of exosomes. Notwithstanding the seemingly promising outcomes from both experimental and clinical studies regarding the therapeutic use of stem cells against ischemic heart disease, positive results from fraud or false data interpretation need to be taken into consideration. The current review is aimed at overviewing the therapeutic application of stem cells in different categories of ischemic heart disease, including relevant experimental and clinical outcomes, as well as the proposed mechanisms underpinning such observations.