Lysyl oxidases expression and histopathological changes of the diabetic rat nephron

Di-PEGylated insulin: A long-acting insulin conjugate with superior safety in reducing hypoglycemic events

Although the discovery of insulin 100 years ago revolutionized the treatment of diabetes, its therapeutic potential is compromised by its short half-life and narrow therapeutic index. Current long-acting insulin analogs, such as insulin-polymer conjugates, are mainly used to improve pharmacokinetics by reducing renal clearance. However, these conjugates are synthesized without sacrificing the bioactivity of insulin, thus retaining the narrow therapeutic index of native insulin, and exceeding the efficacious dose still leads to hypoglycemia. Here, we report a kind of di-PEGylated insulin that can simultaneously reduce renal clearance and receptor-mediated clearance. By impairing the binding affinity to the receptor and the activation of the receptor, di-PEGylated insulin not only further prolongs the half-life of insulin compared to classical mono-PEGylated insulin but most importantly, increases its maximum tolerated dose 10-fold. The target of long-term glycemic management in vivo has been achieved through improved pharmacokinetics and a high dose. This work represents an essential step towards long-acting insulin medication with superior safety in reducing hypoglycemic events.

Integrative analysis of potential diagnostic markers and therapeutic targets for glomerulus-associated diabetic nephropathy based on cellular senescence

Introduction

Diabetic nephropathy (DN), distinguished by detrimental changes in the renal glomeruli, is regarded as the leading cause of death from end-stage renal disease among diabetics. Cellular senescence plays a paramount role, profoundly affecting the onset and progression of chronic kidney disease (CKD) and acute kidney injuries. This study was designed to delve deeply into the pathological mechanisms between glomerulus-associated DN and cellular senescence.

Methods

Glomerulus-associated DN datasets and cellular senescence-related genes were acquired from the Gene Expression Omnibus (GEO) and CellAge database respectively. By integrating bioinformatics and machine learning methodologies including the LASSO regression analysis and Random Forest, we screened out four signature genes. The receiver operating characteristic (ROC) curve was performed to evaluate the diagnostic performance of the selected genes. Rigorous experimental validations were subsequently conducted in the mouse model to corroborate the identification of three signature genes, namely LOX, FOXD1 and GJA1. Molecular docking with chlorogenic acids (CGA) was further established not only to validate LOX, FOXD1 and GJA1 as diagnostic markers but also reveal their potential therapeutic effects.

Results and discussion

In conclusion, our findings pinpointed three diagnostic markers of glomerulus-associated DN on the basis of cellular senescence. These markers could not only predict an increased risk of DN progression but also present promising therapeutic targets, potentially ushering in innovative treatments for DN in the elderly population.

Lysyl oxidase like-2 in fibrosis and cardiovascular disease

Fibrosis is an important and essential reparative response to injury that, if left uncontrolled, results in the excessive synthesis, deposition, remodeling, and stiffening of the extracellular matrix, which is deleterious to organ function. Thus, the sustained activation of enzymes that catalyze matrix remodeling and cross linking is a fundamental step in the pathology of fibrotic diseases. Recent studies have implicated the amine oxidase lysyl oxidase like-2 (LOXL2) in this process and established significantly elevated expression of LOXL2 as a key component of profibrotic conditions in several organ systems. Understanding the relationship between LOXL2 and fibrosis as well as the mechanisms behind these relationships can offer significant insights for developing novel therapies. Here, we summarize the key findings that demonstrate the link between LOXL2 and fibrosis and inflammation, examine current therapeutics targeting LOXL2 for the treatment of fibrosis, and discuss future directions for experiments and biomedical engineering.

Paraquat induced oxidative stress, DNA damage, and cytotoxicity in lymphocytes

Paraquat (PQ) is a herbicide belonging to the group of bipyridylium salts. The objective of this study was to evaluate oxidative stress, DNA damage, and cytotoxicity induced by paraquat in peripheral lymphocyte cells in vivo as well as pathological changes in various tissues. For this purpose, 28 male Wistar rats in 6 different groups were poisoned by paraquat gavage and blood samples were taken from the hearts of rats after during the poisoning period. Oxidative stress, DNA damage, cell membrane integrity, serum lactate dehydrogenase, and cytotoxicity, were investigated by Ferric Reducing Antioxidant Potential (FRAP) test, alkaline comet assay, measuring serum lactate dehydrogenase (LDH), Hoechst staining and flow cytometry with propidium iodide (PI) respectively. The lung, kidney, and liver tissues were also examined pathologically. Paraquat caused dose-dependent DNA damage in peripheral lymphocyte cells and significant oxidative cell membrane damage. The most damage was caused by a single dose of 200 mg/kg b.w of paraquat by gavage. The gradual exposure to a dose of 300 mg/kg b.w of paraquat showed less damage, which could be due to the activation of the antioxidant defense mechanism.

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Paraquat induced oxidative stress.

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Paraquat increases serum lactate dehydrogenase.

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Oxidative stress Inducted by exposure to paraquat Inducted DNA damage.

Gene Networks of Hyperglycemia, Diabetic Complications, and Human Proteins Targeted by SARS-CoV-2: What Is the Molecular Basis for Comorbidity?

People with diabetes are more likely to have severe COVID-19 compared to the general population. Moreover, diabetes and COVID-19 demonstrate a certain parallelism in the mechanisms and organ damage. In this work, we applied bioinformatics analysis of associative molecular networks to identify key molecules and pathophysiological processes that determine SARS-CoV-2-induced disorders in patients with diabetes. Using text-mining-based approaches and ANDSystem as a bioinformatics tool, we reconstructed and matched networks related to hyperglycemia, diabetic complications, insulin resistance, and beta cell dysfunction with networks of SARS-CoV-2-targeted proteins. The latter included SARS-CoV-2 entry receptors (ACE2 and DPP4), SARS-CoV-2 entry associated proteases (TMPRSS2, CTSB, and CTSL), and 332 human intracellular proteins interacting with SARS-CoV-2. A number of genes/proteins targeted by SARS-CoV-2 (ACE2, BRD2, COMT, CTSB, CTSL, DNMT1, DPP4, ERP44, F2RL1, GDF15, GPX1, HDAC2, HMOX1, HYOU1, IDE, LOX, NUTF2, PCNT, PLAT, RAB10, RHOA, SCARB1, and SELENOS) were found in the networks of vascular diabetic complications and insulin resistance. According to the Gene Ontology enrichment analysis, the defined molecules are involved in the response to hypoxia, reactive oxygen species metabolism, immune and inflammatory response, regulation of angiogenesis, platelet degranulation, and other processes. The results expand the understanding of the molecular basis of diabetes and COVID-19 comorbidity.

Promising Antifungal Activity of Encephalartos laurentianus de Wild against Candida albicans Clinical Isolates: In Vitro and In Vivo Effects on Renal Cortex of Adult Albino Rats

Candida albicans can cause various infections, especially in immunocompromised patients. Its ability to develop resistance to the current antifungal drugs as well as its multiple virulence factors have rendered the problem even more complicated. Thus, in the present investigation, we elucidated an in vitro and in vivo antifungal activity of Encephalartos laurentianus methanol extract (ELME) against C. albicans clinical isolates for the first time. A phytochemical identification of 64 compounds was conducted in ELME using LC-MS/MS. Interestingly, ELME exhibited antifungal activity with MIC values that ranged from 32–256 µg/mL. Furthermore, we investigated the antibiofilm activity of ELME against the biofilms formed by C. albicans isolates. ELME displayed antibiofilm activity using a crystal violet assay as it decreased the percentages of cells, moderately and strongly forming biofilms from 62.5% to 25%. Moreover, the antibiofilm impact of ELME was elucidated using SEM and fluorescent microscope. A significant reduction in the biofilm formation by C. albicans isolates was observed. In addition, we observed that ELME resulted in the downregulation of the biofilm-related tested genes (ALS1, BCR1, PLB2, and SAP5) in 37.5% of the isolates using qRT-PCR. Besides, the in vivo antifungal activity of ELME on the kidney tissues of rats infected with C. albicans was investigated using histological and immunohistochemical studies. ELME was found to protect against C. albicans induced renal damage, decrease desmin and inducible nitric oxide synthase, increase alkaline phosphatase, and increase infected rats’ survival rate. Additionally, the cytotoxicity of ELME was elucidated on Human Skin Fibroblast normal cells using MTT assay. ELME had an IC50 of 31.26 µg/mL. Thus, we can conclude that ELME might be a promising future source for antifungal compounds.

Corneal biomechanical properties in patients with kidney transplant

PURPOSE

The purpose of the study was to evaluate the corneal biomechanical properties in patients post kidney transplant and to compare them with healthy age-matched control.

MATERIALS AND METHODS

In this cross-sectional study, 68 patients with kidney transplant (study group) and 68 healthy individuals (control group) were analyzed with ocular response analyzer measurements. Only the right eye of each participant was assessed for corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOP_cc), and Goldmann-correlated intraocular pressure (IOP_g).

RESULTS

The mean CH in the study group was 9.70 ± 1.62 mmHg which was significantly lower than the control group with the mean CH of 10.60 ± 1.49 mmHg (P = 0.001). The mean IOP_cc was 18.17 ± 4.00 mmHg and 16.00 ± 3.94 mmHg in the study and control groups, respectively (P = 0.002). CRF and IOP_g were not significantly different between groups.

CONCLUSION

CH and IOP_ccare altered in kidney transplant patients.

Ameliorating Fibrotic Phenotypes of Keloid Dermal Fibroblasts through an Epidermal Growth Factor-Mediated Extracellular Matrix Remodeling

Keloid and hypertrophic scars are skin fibrosis-associated disorders that exhibit an uncontrollable proliferation of fibroblasts and their subsequent contribution to the excessive accumulation of extracellular matrix (ECM) in the dermis. In this study, to elucidate the underlying mechanisms, we investigated the pivotal roles of epidermal growth factor (EGF) in modulating fibrotic phenotypes of keloid and hypertrophic dermal fibroblasts. Our initial findings revealed the molecular signatures of keloid dermal fibroblasts and showed the highest degree of skin fibrosis markers, ECM remodeling, anabolic collagen-cross-linking enzymes, such as lysyl oxidase (LOX) and four LOX-like family enzymes, migration ability, and cell–matrix traction force, at cell–matrix interfaces. Furthermore, we observed significant EGF-mediated downregulation of anabolic collagen-cross-linking enzymes, resulting in amelioration of fibrotic phenotypes and a decrease in cell motility measured according to the cell–matrix traction force. These findings offer insight into the important roles of EGF-mediated cell–matrix interactions at the cell–matrix interface, as well as ECM remodeling. Furthermore, the results suggest their contribution to the reduction of fibrotic phenotypes in keloid dermal fibroblasts, which could lead to the development of therapeutic modalities to prevent or reduce scar tissue formation.

Mapping the genetic basis of diabetes mellitus in the Australian Burmese cat (Felis catus)

Diabetes mellitus, a common endocrinopathy affecting domestic cats, shares many clinical and pathologic features with type 2 diabetes in humans. In Australia and Europe, diabetes mellitus is almost four times more common among Burmese cats than in other breeds. As a genetically isolated population, the diabetic Australian Burmese cat provides a spontaneous genetic model for studying diabetes mellitus in humans. Studying complex diseases in pedigreed breeds facilitates tighter control of confounding factors including population stratification, allelic frequencies and environmental heterogeneity. We used the feline SNV array and whole genome sequence data to undertake a genome wide-association study and runs of homozygosity analysis, of a case–control cohort of Australian and European Burmese cats. Our results identified diabetes-associated haplotypes across chromosomes A3, B1 and E1 and selective sweeps across the Burmese breed on chromosomes B1, B3, D1 and D4. The locus on chromosome B1, common to both analyses, revealed coding and splice region variants in candidate genes, ANK1, EPHX2 and LOX2, implicated in diabetes mellitus and lipid dysregulation. Mapping this condition in Burmese cats has revealed a polygenic spectrum, implicating loci linked to pancreatic beta cell dysfunction, lipid dysregulation and insulin resistance in the pathogenesis of diabetes mellitus in the Burmese cat.

Recent advances in understanding the role of hypoxia-inducible factor 1α in renal fibrosis

Renal fibrosis is the most common pathological manifestation of chronic kidney disease (CKD), and with numerous influencing factors, its pathogenesis is complex. Epithelial-mesenchymal transition (EMT) is known to promote the progression of renal fibrosis via alterations in the secreted proteome. Moreover, blocking or even reversing EMT can effectively reduce the degree of fibrosis. As such, targeting the key molecules responsible for promoting EMT may be an effective strategy for inhibiting renal fibrosis. Research in recent years has demonstrated that hypoxia-inducible factor 1α (HIF-1α) acts to promote renal fibrosis through regulation of EMT. However, the relationship between HIF-1α and EMT remains incompletely understood. In the present review, the underlying mechanism of the interaction between HIF-1α and EMT is explored to provide novel insight into the pathogenesis of renal fibrosis and new ideas for early targeted intervention.

Upregulation of Lysyl Oxidase Expression in Vitreous of Diabetic Subjects: Implications for Diabetic Retinopathy

Animal studies have shown diabetes-induced lysyl oxidase (LOX) upregulation promotes blood-retinal-barrier breakdown and retinal vascular cell loss associated with diabetic retinopathy (DR). However, it is unclear whether changes in LOX expression contribute to the development and progression of DR. To determine if vitreous LOX levels are altered in patients with DR, 31 vitreous specimens from subjects with advanced proliferative DR (PDR), and 27 from non-diabetics were examined. The two groups were age- and gender-matched (57 ± 12 yrs vs. 53 ± 18 yrs; 19 males and 12 females vs. 17 males and 10 females). Vitreous samples obtained during vitrectomy were assessed for LOX levels using ELISA. LOX was detected in a larger number of PDR subjects (58%) than in non-diabetic subjects (15%). Additionally, ELISA measurements showed a significant increase in LOX levels in the diabetic subjects with PDR, compared to those of non-diabetic subjects (68.3 ± 112 ng/mL vs. 2.1 ± 8.2 ng/mL; p < 0.01). No gender difference in vitreous LOX levels was observed in either the diabetic or non-diabetic groups. Findings support previous reports of increased LOX levels in retinas of diabetic animals and in retinal vascular cells in high glucose condition, raising the prospect of targeting LOX overexpression as a potential target for PDR treatment.

Emerging Factors Implicated in Fibrotic Organ-Associated Thrombosis: The Case of Two Organs

Thrombosis is at the heart of cardiovascular complications observed in specific diseases. A heightened thrombosis risk above that in general population in diseases such as myelofibrosis and chronic kidney disease implicates disease-specific mediators of thrombosis. This relative lack of information regarding the mechanisms of thrombosis in specific organ pathologies hitherto has remained limited. Evolving literature implicates some soluble factors in the blood of patients with discrete disorders, inflicting fundamental changes in the components of thrombosis. In this era of precision medicine, integrating these disease-specific factors in a comprehensive thrombotic risk assessment of patients is imperative in guiding therapeutic decisions. A complex network of mechanisms regulates each organ pathology and resultant thrombotic phenotypes. This review surveys different effectors of thrombogenicity associated with two pathologically fibrotic organs used as model systems, the bone marrow and kidney, as well as focuses attention to a common inducer of fibrosis and thrombosis, lysyl oxidase.

Decreased lysyl oxidase level protects against development of retinal vascular lesions in diabetic retinopathy

Retinal capillary basement membrane (BM) thickening is closely associated with the development of vascular lesions in diabetic retinopathy. Thickened capillary BM can compromise blood-retinal-barrier characteristics and contribute to retinal vascular permeability, a significant clinical manifestation of diabetic retinopathy. We have previously shown that high glucose increases the expression and activity of lysyl oxidase (LOX), a crosslinking enzyme, in retinal endothelial cells. Additionally, concomitant with overexpression of LOX, increased vascular permeability was observed in diabetic rat retinas. However, it is unknown whether decreasing LOX overexpression may have protective effects against development of retinal vascular lesions in diabetes. To investigate whether reduced LOX level protects against diabetes-induced development of retinal vascular lesions characteristic of diabetic retinopathy, four groups of mice: wild type (WT) control mice, streptozotocin (STZ)-induced diabetic mice, LOX +/- mice, and STZ-induced diabetic LOX +/- mice were used for this study. Diabetes was maintained for 16 weeks; at the end of the study, retinas were assessed for LOX protein level by Western Blot (WB) analysis, and retinal capillary networks were isolated using retinal trypsin digestion and stained with hematoxylin and periodic acid Schiff to identify the number of acellular capillaries (AC) and pericyte loss (PL). In parallel, TUNEL assay was performed on retinal trypsin digests (RTDs) to detect cells undergoing apoptosis in the retinal capillary networks. Retinal vascular permeability was analyzed following FITC-dextran injection in retinal whole mounts. A significant increase in LOX expression was detected in the diabetic retinas compared to those of the WT control retinas, and as expected, a significant decrease in LOX expression in the diabetic LOX +/- retinas was observed compared to those of the diabetic retinas. RTD images showed significantly increased AC and PL counts in the retinas of diabetic mice compared to those of the WT control mice. Importantly, the number of AC and PL was significantly decreased, as was retinal vascular permeability in the retinas of the diabetic LOX +/- mice compared to those of the diabetic mice. Results suggest that decreasing diabetes-induced LOX overexpression may have protective effects against the development of vascular lesions characteristic of diabetic retinopathy. Therefore, LOX overexpression may be a potential target in preventing retinal vascular cell loss and excess permeability associated with diabetic retinopathy.