A promising therapeutic peptide and preventive/diagnostic biomarker for age-related diseases: The Elabela/Apela/Toddler peptide

Structural insights into the regulation of monomeric and dimeric apelin receptor

The apelin receptor (APJR) emerges as a promising drug target for cardiovascular health and muscle regeneration. While prior research unveiled the structural versatility of APJR in coupling to Gi proteins as a monomer or dimer, the dynamic regulation within the APJR dimer during activation remains poorly understood. In this study, we present the structures of the APJR dimer and monomer complexed with its endogenous ligand apelin-13. In the dimeric structure, apelin-13 binds exclusively to one protomer that is coupled with Gi proteins, revealing a distinct ligand-binding behavior within APJR homodimers. Furthermore, binding of an antagonistic antibody induces a more compact dimerization by engaging both protomers. Notably, structural analyses of the APJR dimer complexed with an agonistic antibody, with or without Gi proteins, suggest that G protein coupling may promote the dissociation of the APJR dimer during activation. These findings underscore the intricate interplay between ligands, dimerization, and G protein coupling in regulating APJR signaling pathways.

The role of maternal blood elabela levels in the prediction of placenta previa and accreta

INTRODUCTION

Placenta previa and Placenta Accreta Spectrum are life-threatening obstetric conditions that are challenging to diagnose accurately. Currently, there is no biochemical parameter available for their diagnosis. The aim of our study is to investigate the potential of Elabela as a laboratory marker that could predict placenta previa and placenta accreta, both of which can lead to severe, life-threatening complications for the mother.

METHODS

In this study, which was conducted prospectively in two tertiary centers between 2020 and 2022, Elabela levels were examined in patient groups with placental insertion and invasion anomalies. SPSS program was used for comparative statistical analysis between groups.

RESULTS

Of the 67 analyzed patients, 32 were in the control group, 12 were in the previa group, and 23 were in the accreta group. There was no statistically significant difference between the groups regarding age, BMI, number of curettages, presence of previous cesarean section, and smoking status. The Elabela level was measured at 135.6 ± 72.1 in the control group, 988.3 ± 925.5 in the previa group, and 376 ± 364.6 in the accreta group, with a statistically significant difference between the groups. The cut-off value of Elabela levels in the previa group was determined to be 304, with a sensitivity of 83.30 % and a specificity of 83.60 % (AUC = 0.909). In the accreta group, the cut-off value was 195.5, with a sensitivity of 60.90 % and a specificity of 61.40 % (AUC = 0.658).

DISCUSSION

By showing that the prediction of placenta previa and placenta acreata can be made with a biochemical parameter in our study, young researchers will focus more on this subject and thus make many contributions to science.

Elabela alleviates cuproptosis and vascular calcification in vitaminD3- overloaded mice via regulation of the PPAR-γ /FDX1 signaling

BACKGROUND

Vascular calcification is a crucial pathophysiological process associated with age-related cardiovascular diseases. Elabela, a recently identified peptide, has emerged as a significant player in the regulation of cardiovascular function and homeostasis. However, the effects and underlying mechanisms of Elabela on age-related vascular calcification remain largely unexplored.

METHODS

In-vivo vascular calcifications of C57BL/6J mice (8-week-old) and young (8-week-old) or aged (72-week-old) SD rats were injected with vitamin D3 (VitD3) or saline, respectively. Furthermore, the VitD3-overloaded mice received Elabela (1 mg/kg/d), peroxisome proliferators-activated receptor-γ (PPAR-γ) activator Rosiglitazone (5 mg/kg/d) or copper-ionophore Elesclomol (20 mg/kg/d), respectively. As for in-vitro studies, primary rat vascular smooth muscle cells (VSMCs) were isolated from aortas and cultured for explore the role and underlying mechanism of Elabela in vascular calcification.

RESULTS

There were marked increases in FDX1 and Slc31a1 levels in both aortas and VSMCs during vascular calcification, coinciding with a rise in copper levels and a decrease in Elabela levels. Alizarin red and von-Kossa staining indicated that the administration of Elabela effectively hindered the progression of vascular cuproptosis and arterial calcification in VitD3-overloaded mice and rat arterial rings models. Moreover, Elabela significantly suppressed osteogenic differentiation and calcium deposition in VSMCs and strikingly reversed high phosphate-induced augmentation of FDX1 expression, DLAT aggregation as well as intracellular copper ion levels. More importantly, Elabela exhibited remarkable abilities to prevent mitochondrial dysfunctions in primary rat VSMCs by maintaining mitochondrial membrane potential, inhibiting mitochondrial division, reducing mitochondrial ROS production and increasing ATP levels. Interestingly, Elabela mitigated cellular senescence and production of pro-inflammatory cytokines including IL-1α, IL-1β, IL-6, IL-18 and TNF-α, respectively. Furthermore, Elabela upregulated the protein levels of PPAR-γ in VitD3-overloaded mice. Administrating PPAR-γ inhibitor GW9662 or blocking the efflux of intracellular copper abolished the protective effect of Elabela on vascular calcification by enhancing levels of FDX1, Slc31a1, Runx2, and BMP2.

CONCLUSION

Elabela plays a crucial role in protecting against vascular cuproptosis and arterial calcification by activating the PPAR-γ /FDX1 signaling. Elabela supplementation and cuproptosis suppression serve as effective therapeutic approaches for managing vascular calcification and related cardiovascular disorders.

Inflammatory Intracellular Signaling in Neurons Is Influenced by Glial Soluble Factors in iPSC-Based Cell Model of PARK2-Associated Parkinson's Disease

Neuroinflammation is considered to be one of the driving factors in Parkinson's disease (PD). This study was conducted using neuronal and glial cell cultures differentiated from induced pluripotent stem cells (iPSC) of healthy donors (HD) and PD patients with different PARK2 mutations (PD). Based on the results of RNA sequencing, qPCR and ELISA, we revealed transcriptional and post-transcriptional changes in HD and PD neurons cultivated in HD and PD glial-conditioned medium. We demonstrated that if one or both of the components of the system, neurons or glia, is Parkin-deficient, the interaction resulted in the down-regulation of a number of key genes related to inflammatory intracellular pathways and negative regulation of apoptosis in neurons, which might be neuroprotective. In PD neurons, the stress-induced up-regulation of APLNR was significantly stronger compared to HD neurons and was diminished by glial soluble factors, both HD and PD. PD neurons in PD glial conditioned medium increased APLN expression and also up-regulated apelin synthesis and release into intracellular fluid, which represented another compensatory action. Overall, the reported results indicate that neuronal self-defense mechanisms contribute to cell survival, which might be characteristic of PD patients with Parkin-deficiency.

Focus of endothelial glycocalyx dysfunction in ischemic stroke and Alzheimer's disease: Possible intervention strategies

The integrity of the endothelial glycocalyx (eGCX), a mixture of carbohydrates attached to proteins expressed on the surface of blood vessel endothelial cells (EC), is critical for the maintenance of homeostasis of the cardiovascular system and all systems of the human body, the endothelium being the critical component of the stroma of all tissues. Consequently, dysfunction of eGCX results in a dysfunctional cardiovascular wall and severe downstream cardiovascular events, which contribute to the onset of cardio- and cerebrovascular diseases and neurodegenerative disorders, as well as other age-related diseases (ARDs). The key role of eGCX dysfunction in the onset of ARDs is examined here, with a focus on the most prevalent neurological diseases: ischemic stroke and Alzheimer's disease. Furthermore, the advantages and limitations of some treatment strategies for anti-eGCX dysfunction are described, ranging from experimental drug therapies, which need to be better tested and explored not only in animal models but also in humans, as well as reprogramming, the use of nutraceuticals, which are emerging as regenerative and new approaches. The promotion of these strategies is essential to keep eGCX and endothelium healthy, as is the development of intravital (e.g., intravascular) tools to estimate eGCX health status and treatment efficacy, which could lead to advanced solutions to address ARDs.

Neuroinflammation and Neurodegenerative Diseases: How Much Do We Still Not Know?

The term "neuroinflammation" defines the typical inflammatory response of the brain closely related to the onset of many neurodegenerative diseases (NDs). Neuroinflammation is well known, but its mechanisms and pathways are not entirely comprehended. Some progresses have been achieved through many efforts and research. Consequently, new cellular and molecular mechanisms, diverse and conventional, are emerging. In listing some of those that will be the subject of our description and discussion, essential are the important roles of peripheral and infiltrated monocytes and clonotypic cells, alterations in the gut-brain axis, dysregulation of the apelinergic system, alterations in the endothelial glycocalyx of the endothelial component of neuronal vascular units, variations in expression of some genes and levels of the encoding molecules by the action of microRNAs (miRNAs), or other epigenetic factors and distinctive transcriptional factors, as well as the role of autophagy, ferroptosis, sex differences, and modifications in the circadian cycle. Such mechanisms can add significantly to understanding the complex etiological puzzle of neuroinflammation and ND. In addition, they could represent biomarkers and targets of ND, which is increasing in the elderly.