An original amino acid formula favours in vitro corneal epithelial wound healing by promoting Fn1, ITGB1, and PGC-1α expression

Mechanisms and therapeutic opportunities in metabolic aberrations of diabetic wounds: a narrative review

Metabolic aberrations are fundamental to the complex pathophysiology and challenges associated with diabetic wound healing. These alterations, induced by the diabetic environment, trigger a cascade of events that disrupt the normal wound-healing process. Key factors in this metabolic alternation include chronic hyperglycemia, insulin resistance, and dysregulated lipid and amino acid metabolism. In this review, we summarize the underlying mechanisms driving these metabolic changes in diabetic wounds, while emphasizing the broad implications of these disturbances. Additionally, we discuss therapeutic approaches that target these metabolic anomalies and how their integration with existing wound-healing treatments may yield synergistic effects, offering promising avenues for innovative therapies.

Exploration of Pharmacological Mechanisms of Dapagliflozin against Type 2 Diabetes Mellitus through PI3K-Akt Signaling Pathway based on Network Pharmacology Analysis and Deep Learning Technology

BACKGROUND

Dapagliflozin is commonly used to treat type 2 diabetes mellitus (T2DM). However, research into the specific anti-T2DM mechanisms of dapagliflozin remains scarce.

OBJECTIVE

This study aimed to explore the underlying mechanisms of dapagliflozin against T2DM.

METHODS

Dapagliflozin-associated targets were acquired from CTD, SwissTargetPrediction, and SuperPred. T2DM-associated targets were obtained from GeneCards and DigSee. VennDiagram was used to obtain the overlapping targets of dapagliflozin and T2DM. GO and KEGG analyses were performed using clusterProfiler. A PPI network was built by STRING database and Cytoscape, and the top 30 targets were screened using the degree, maximal clique centrality (MCC), and edge percolated component (EPC) algorithms of CytoHubba. The top 30 targets screened by the three algorithms were intersected with the core pathway-related targets to obtain the key targets. DeepPurpose was used to evaluate the binding affinity of dapagliflozin with the key targets.

RESULTS

In total, 155 overlapping targets of dapagliflozin and T2DM were obtained. GO and KEGG analyses revealed that the targets were primarily enriched in response to peptide, membrane microdomain, protein serine/threonine/tyrosine kinase activity, PI3K-Akt signaling pathway, MAPK signaling pathway, and AGE-RAGE signaling pathway in diabetic complications. AKT1, PIK3CA, NOS3, EGFR, MAPK1, MAPK3, HSP90AA1, MTOR, RELA, NFKB1, IKBKB, ITGB1, and TP53 were the key targets, mainly related to oxidative stress, endothelial function, and autophagy. Through the DeepPurpose algorithm, AKT1, HSP90AA1, RELA, ITGB1, and TP53 were identified as the top 5 anti-targets of dapagliflozin.

CONCLUSION

Dapagliflozin might treat T2DM mainly by targeting AKT1, HSP90AA1, RELA, ITGB1, and TP53 through PI3K-Akt signaling.

Mineralocorticoid receptor expression and the effects of the mineralocorticoid receptor antagonist spironolactone in a murine model of graft-versus-host disease

PURPOSE

The topical administration of spironolactone, a mineralocorticoid receptor antagonist (MRA) improves dry eye symptoms in patients with ocular graft-versus-host disease (GVHD); however, the detailed mechanism remains unclear. This study aimed to investigate the effects of spironolactone eyedrops on the ocular surface using a chronic GVHD (cGVHD) mouse model and to determine the expression of the mineralocorticoid receptor (MR).

METHODS

A cGVHD mouse model was established by allogeneic bone marrow transplantation (BMT) from B10.D2 mice to BALB/c mice. Subsequently, cGVHD mice were treated with either 0.005 % spironolactone or vehicle eyedrops. The eyelids, cornea and conjunctiva of the recipients were analyzed at 4-week intervals post-BMT in both groups.

RESULTS

Signs of ocular GVHD, such as corneal epithelial damage, depletion of meibomian glands, and inflammatory cell infiltration onto the ocular surface, were significantly decreased in cGVHD mice treated with spironolactone eyedrops. The expression of the MR NR3C2 in the corneal and conjunctival epithelia was significantly increased in cGVHD mice. HSP47+NR3C2+ MR-expressing fibroblasts, CD45+NR3C2+ MR-expressing leukocytes, and CD4+NR3C2+ MR-expressing T cells infiltrated the ocular surface tissue of cGVHD mice significantly more than that of syngeneic controls.

CONCLUSIONS

MR expression is increased in epithelial cells, fibroblasts, and T cells in a murine cGVHD model, whereas MRA and spironolactone eyedrops could attenuate the severity of ocular GVHD. These findings suggest that MR signaling partially contributes to the development of ocular GVHD in this mouse model.

Shared and Compartment-Specific Processes in Nucleus Pulposus and Annulus Fibrosus During Intervertebral Disc Degeneration

Elucidating how cell populations promote onset and progression of intervertebral disc degeneration (IDD) has the potential to enable more precise therapeutic targeting of cells and mechanisms. Single-cell RNA-sequencing (scRNA-seq) is performed on surgically separated annulus fibrosus (AF) (19,978; 26,983 cells) and nucleus pulposus (NP) (20,884; 24,489 cells) from healthy and diseased human intervertebral discs (IVD). In both tissue types, depletion of cell subsets involved in maintenance of healthy IVD is observed, specifically the immature cell subsets - fibroblast progenitors and stem cells - indicative of an impairment of normal tissue self-renewal. Tissue-specific changes are also identified. In NP, several fibrotic populations are increased in degenerated IVD, indicating tissue-remodeling. In degenerated AF, a novel disease-associated subset is identified, which expresses disease-promoting genes. It is associated with pathogenic biological processes and the main gene regulatory networks include thrombospondin signaling and FOXO1 transcription factor. In NP and AF cells thrombospondin protein promoted expression of genes associated with TGFβ/fibrosis signaling, angiogenesis, and nervous system development. The data reveal new insights of both shared and tissue-specific changes in specific cell populations in AF and NP during IVD degeneration. These identified mechanisms and molecules are novel and more precise targets for IDD prevention and treatment.

Endothelium-specific deletion of p62 causes organ fibrosis and cardiac dysfunction

BACKGROUND

The autophagy adapter SQSTM1/p62 is crucial for maintaining homeostasis in various organs and cells due to its protein-protein interaction domains and involvement in diverse physiological and pathological processes. Vascular endothelium cells play a unique role in vascular biology and contribute to vascular health.

METHODS

Using the Cre-loxP system, we generated mice with endothelium cell-specific knockout of p62 mediated by Tek (Tek receptor tyrosine kinase)-cre to investigate the essential role of p62 in the endothelium. In vitro, we employed protein mass spectrometry and IPA to identify differentially expressed proteins upon knockdown of p62. Immunoprecipitation assays were conducted to demonstrate the interaction between p62 and FN1 or LAMC2 in human umbilical vein endothelium cells (HUVECs). Additionally, we identified the degradation pathway of FN1 and LAMC2 using the autophagy inhibitor 3-methyladenine (3-MA) or proteasome inhibitor MG132. Finally, the results of immunoprecipitation demonstrated that the interaction between p62 and LAMC2 was abolished in the PB1 truncation group of p62, while the interaction between p62 and FN1 was abolished in the UBA truncation group of p62.

RESULTS

Our findings revealed that p62 Endo mice exhibited heart, lung, and kidney fibrosis compared to littermate controls, accompanied by severe cardiac dysfunction. Immunoprecipitation assays provided evidence of p62 acting as an autophagy adapter in the autophagy-lysosome pathway for FN1 and LAMC2 degradation respectively through PB1 and UBA domain with these proteins rather than proteasome system.

CONCLUSIONS

Our study demonstrates that defects in p62 within endothelium cells induce multi-organ fibrosis and cardiac dysfunction in mice. Our findings indicate that FN1 and LAMC2, as markers of (EndoMT), have detrimental effects on HUVECs and elucidate the autophagy-lysosome degradation mechanism of FN1 and LAMC2.

Liraglutide intervention improves high-glucose-induced reactive gliosis of Müller cells and ECM dysregulation

Reactive gliosis of Müller cells plays an important role in the pathogenesis of diabetic retinopathy (DR). Liraglutide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been shown to improve DR by inhibiting reactive gliosis. However, the mechanism of inhibition has yet to be elucidated. This study investigated the effects of liraglutide on Müller glia reactivity in the early stages of DR and the underlying mechanisms. Proteomics combined with bioinformatics analysis, HE staining, and immunofluorescence staining revealed ganglion cell loss, reactive gliosis of Müller cells, and extracellular matrix (ECM) imbalance in rats with early stages of DR. High glucose (HG) exposure up-regulated GFAP and TNF-α expression and down-regulated ITGB1 expression and FN1 content in extracellular fluid in rMC1 cells, thereby promoting reactive gliosis. GLP-1R knockdown and HG+DAPT inhibition experiments show that liraglutide balances ECM levels by inhibiting activation of the Notch1/Hes1 pathway and ameliorates high-glucose-induced Müller glia reactivity. Thus, the study provides new targets and ideas for improvement of DR in early stages.

Collagen Crosslinking for Keratoconus: Cellular Signaling Mechanisms

Collagen crosslinking (CXL) is a widely used treatment to halt the progression of keratoconus (KC). Unfortunately, a significant number of patients with progressive KC will not qualify for CXL, including those with corneas thinner than 400 µm. The present study aimed to investigate the molecular effects of CXL using in vitro models, mirroring the normal, as well as thinner corneal stroma seen in KCs. Primary human corneal stromal cells were isolated from healthy (HCFs) and keratoconus (HKCs) donors. Cells were cultured and stimulated with stable Vitamin C resulting in 3D self-assembled extracellular matrix (ECM), cell-embedded, constructs. CXL was performed on (a) thin ECM with CXL performed at week 2 and (b) normal ECM with CXL performed at week 4. Constructs without CXL served as controls. All constructs were processed for protein analysis. The results showed modulation of Wnt signaling, following CXL treatment, as measured by the protein levels of Wnt7b and Wnt10a, correlated to the expression of α-smooth muscle actin (SMA). Further, the expression of a recently identified KC biomarker candidate, prolactin-induced protein (PIP), was positively impacted by CXL in HKCs. CXL-driven upregulation of PGC-1 and the downregulation of SRC and Cyclin D1 in HKCs were also noted. Although the cellular/molecular impacts of CXL are largely understudied, our studies provide an approximation to the complex mechanisms of KC and CXL. Further studies are warranted to determine factors influencing CXL outcomes.