Netrin as a Novel Biomarker and Its Therapeutic Implications in Diabetes Mellitus and Diabetes-Associated Complications

Transient renal tubular injury among children and adolescents during diabetic ketoacidosis: severity, renal perfusion, and urinary netrin- 1 interplay

Acute kidney injury (AKI) has been reported during diabetic ketoacidosis (DKA). Evidence regarding tubulopathy is less established, with its pathophysiology, risk determinants, and short-term outcome to be unraveled. Hence, this study aimed to assess renal tubular functions during DKA, its short-term outcome, and its relation with urinary Netrin-1, DKA severity, and renal perfusion indices. Forty children and adolescents (20 with moderate and 20 with severe DKA) were assessed for urine output (UOP), blood pressure, blood glucose, HbA1c, and urinary Netrin-1, with calculation of serum osmolality and estimated glomerular filtration rate (eGFR). Renal pulsatility and resistivity indices were assessed by renal duplex. Reevaluation was done on days 3 and 14. Sixteen children and adolescents had tubular proteinuria during DKA (40%). Their mean urine output (UOP) during DKA was 14.03 cc/kg/h, and their mean urinary Netrin-1 was 836.9 ng/ml. A significant improvement was observed in the UOP, protein/creatinine ratio, urinary netrin, and serum osmolality after the resolution of DKA accompanied by a significant decrease in renal resistivity and pulsatility indices (p < 0.05). A significant positive correlation was found between tubular proteinuria during DKA and urinary Netrin-1, renal pulsatility, and resistivity indices (p < 0.05). Multivariate regression analysis revealed that serum PH and urinary Netrin-1 were the most significant independent variables associated with tubular proteinuria among children and adolescents during DKA.

CONCLUSION

Transient renal tubulopathy occurs during DKA manifested by tubular proteinuria, polyuria, and hypokalemia; that is correlated with DKA severity, renal perfusion indices, and urinary Netrin-1 and reversible by day 14 post-DKA. Netrin-1 could serve as a potential therapeutic target for DKA-associated tubulopathy.

WHAT IS KNOWN

• Diabetic ketoacidosis (DKA) is a severe acute complication of diabetes mellitus, with negative effect on multiple body organs. • Studies increasingly suggest acute kidney injury during DKA, however, data about renal tubular injury during DKA, it's pathophysiology, risk determinants and short term outcomes are still unclear.

WHAT IS NEW

• Transient renal tubulopathy was reported in 40 % the studied children and adolescents during DKA manifested by proteinuria, polyurea, and hypokalemia. • This tubulopathy that was correlated with DKA severity, renal perfusion indices and urinary Netrin-1 and totally reversible by day 14 post DKA.

Microbiota and Inflammatory Markers: A Review of Their Interplay, Clinical Implications, and Metabolic Disorders

The human microbiota, a complex ecosystem of microorganisms, plays a pivotal role in regulating host immunity and metabolism. This review investigates the interplay between microbiota and inflammatory markers, emphasizing their impact on metabolic and autoimmune disorders. Key inflammatory biomarkers, such as C-reactive protein (CRP), interleukin-6 (IL-6), lipopolysaccharides (LPS), zonulin (ZO-1), and netrin-1 (Ntn1), are discussed in the context of intestinal barrier integrity and chronic inflammation. Dysbiosis, characterized by alterations in microbial composition and function, directly modulates the levels and activity of these biomarkers, exacerbating inflammatory responses and compromising epithelial barriers. The disruption of microbiota is further correlated with increased intestinal permeability and chronic inflammation, serving as a precursor to conditions like type 2 diabetes (T2D), obesity, and non-alcoholic fatty liver disease. Additionally, this review examines therapeutic strategies, including probiotics and prebiotics, designed to restore microbial balance, mitigate inflammation, and enhance metabolic homeostasis. Emerging evidence positions microbiota-targeted interventions as critical components in the advancement of precision medicine, offering promising avenues for diagnosing and treating inflammatory and metabolic disorders.

Identification, molecular characterization, and in silico structural analysis of larval salivary glands Netrin-A as a potent biomarker from Lucilia sericata (Diptera: Calliphoridae)

The greenbottle blowfly Lucilia sericata (L. sericata) is increasingly used in larval therapy of chronic wounds. Netrins as bifunctional proteins are in the superfamily of Laminins secreted from larval salivary glands. The Netrin protein has a significant instructive role in axon guidance, causing neuronal outgrowth, angiogenesis, and cell migration. It seems to be crucial in wound healing and acts as a potential biomarker in diagnosing some clinical diseases. This survey aimed to identify molecular features and analyze in silico structural configuration of Netrin-A in L. sericata larvae. The larvae were reared under standard maggotarium conditions. The nucleic acid sequence of L. sericata Netrin-A (LSN-A) was then identified using rapid amplification of circular DNA ends (RACE) and rapid amplification of genomic ends (RAGE). Parts of the Netrin-A gene, including the middle, 3'-, and 5'-ends, were identified, TA cloned in pTG19 plasmid, and transferred into DH5ɑ Escherichia coli. Each part was sequenced and assembled using SeqMan software. This gene structure was further subjected to in silico analysis. The DNA of LSN-A was identified to be 2407 bp, while its mRNA sequence was recognized as 2115 bp by Oligo0.7 software. It translated the Netrin-A protein with 704 amino acid residues. Its estimated molecular weight was 78.6 kDa. Sequencing of this fragment and its BLAST analysis revealed laminin-based high (95%) similarity with the mRNA sequence of Lucilia cuprina Netrin-A. The 3-D structure of Netrin-A drawn by SWISS-MODEL exhibited its partial resemblance to the reference molecule Netrin-1 of Homo sapiens. This study supports the molecular and structural analyses of LSN-A protein, which could lead to wound treatment. Ultimately, it can be an effective candidate to ameliorate injury. Our next attempt is to produce LSN-A recombinant protein for use in biomedical sciences.

Biomarkers in Diabetes Mellitus

Diabetes mellitus (DM) is a chronic metabolic disease characterized by hyperglycemia that occurs as a result of impaired insulin secretion and/or insulin effect, or both of these factors. The fact that the disease has both individual and social dimensions makes it important to detect as early as possible and make the necessary lifestyle changes. For this purpose, it becomes necessary to develop fast, effortless, cheap, and reliable methods for diagnosis. We discussed which biochemical markers should enter routine use according to their sensitivity and specificity among the biochemical markers that have been used and are still being studied. In this chapter, we explored some methods that may be used as biomarkers and discussed advantages and pitfalls for each.

Interleukin-34 promotes tumorigenic signals for colon cancer cells

Colorectal carcinoma (CRC) is one of the most common forms of malignancy in the Western world. Accumulating evidence indicates that colon carcinogenesis is tightly controlled by tumour-associated immune cells and stromal cells, which can either stimulate or suppress CRC cell growth and survival, mainly via the production of cytokines. Interleukin-34 (IL-34), a cytokine known to regulate mainly monocyte/macrophage survival and function, is highly produced within the CRC microenvironment by several cell types, including cancer cells, tumour-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs), and regulates the pro-tumoural functions of such cells. In this article, we summarize the available data supporting the multiple effects of IL-34 in human CRC.

Serum netrin and VCAM-1 as biomarker for Egyptian patients with type IΙ diabetes mellitus

OBJECTIVE

This study aimed to evaluate the serum level of netrin and soluble vascular cell adhesion molecule 1 (VCAM-I) in patients with type IΙ diabetes mellitus (T2DM) and evaluate the association of their levels with the development of a diabetic complication.

PATIENTS AND METHODS

This study was carried out on type II diabetic patients with and without complications and healthy individuals served as controls. All subjects were submitted to the estimation of serum lipid profile, serum creatinine, urinary albumin/creatinine ratio (ACR), fasting blood glucose (FBG), glycated hemoglobin (HbA1c), visceral adiposity index (VAI), atherogenic index of plasma (AIP), lipid accumulation product (LAP) and detection of serum level of netrin1 and VCAM1.

RESULTS

Diabetic patients with complications had significantly higher serum levels of creatinine, ACR, cholesterol, Triglyceride, low-density lipoprotein, netrin1, and VCAM1 than diabetic patients without complications. Likewise, the level of VAI and LAP as markers of excessive body fat were significantly higher in diabetic patients with complications than diabetic patients without complications. The netrin1 and VCAM1 were a significant discriminator of T2DM renal complications with a sensitivity of 96%, 90%, and specificity of 82.7%, 91.3% respectively.

CONCLUSION

It can be concluded that serum netrin1 and VCAM1 correlated significantly with markers of excessive body fat, a renal complication in the patient with type 2 diabetes mellitus.

Emerging Diabetic Novel Biomarkers of the 21st Century

Diabetes is a growing epidemic with estimated prevalence of infected to reach ~592 million by the year 2035. An effective way to approach is to detect the disease at a very early stage to reduce the complications and improve lifestyle management. Although several traditional biomarkers including glucated hemoglobin, glucated albumin, fructosamine, and 1,5-anhydroglucitol have helped in ease of diagnosis, there is lack of sensitivity and specificity and are inaccurate in certain clinical settings. Thus, search for new and effective biomarkers is a continuous process with an aim of accurate and timely diagnosis. Several novel biomarkers have surged in the present century that are helpful in timely detection of the disease condition. Although it is accepted that a single biomarker will have its inherent limitations, combining several markers will help to identify individuals at high risk of developing prediabetes and eventually its progression to frank diabetes. This review describes the novel biomarkers of the 21st century, both in type 1 and type 2 diabetes mellitus, and their present potential for assessing risk stratification due to insulin resistance that will pave the way for improved clinical outcome.

Netrin-1 functions as a suppressor of bone morphogenetic protein (BMP) signaling

Netrin-1 is a secreted protein that is well known for its involvement in axonal guidance during embryonic development and as an enhancer of cancer cell metastasis. Despite extensive efforts, the molecular mechanisms behind many of the physiological functions of netrin-1 have remained elusive. Here, we show that netrin-1 functions as a suppressor of bone morphogenetic protein (BMP) signaling in various cellular systems, including a mutually inhibitory interaction with the BMP-promoting function of leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins. The BMP inhibitory function of netrin-1 in mouse embryonic fibroblasts was dependent on the netrin receptor neogenin, with the expression level regulated by both netrin-1 and LRIG proteins. Our results reveal a previously unrecognized function of netrin-1 that may help to explain several of the developmental, physiological, and cancer-promoting functions of netrins at the signal transduction level.

Prominent and emerging anti-diabetic molecular targets

Diabetes is on the rise across the globe affecting more than 463 million people and crucially increasing morbidities of diabetes-associated diseases. Urgent and immense actions are needed to improve diabetes prevention and treatment. Regarding the correlation of diabetes with many associated diseases, inhibition of the disease progression is more crucial than controlling symptoms. Currently, anti-diabetic drugs are accompanied by undesirable side-effects and target confined types of biomolecules. Thus, extensive research is demanding to identify novel disease mechanisms and molecular targets as probable candidates for effective treatment of diabetes. This review discusses the conventional molecule targets that have been applied for their therapeutic rationale in treatment of diabetes. Further, the emerging and prospective molecular targets for the future focus of library screenings are presented.

Interleukin-34 Enhances the Tumor Promoting Function of Colorectal Cancer-Associated Fibroblasts

The stromal compartment of colorectal cancer (CRC) is marked by the presence of large numbers of fibroblasts, termed cancer-associated fibroblasts (CAFs), which promote CRC growth and progression through the synthesis of various molecules targeting the neoplastic cells. Interleukin (IL)-34, a cytokine over-produced by CRC cells, stimulates CRC cell growth. Since IL-34 also regulates the function of inflammatory fibroblasts, we hypothesized that it could regulate the tumor promoting function of colorectal CAFs. By immunostaining and real-time PCR, we initially showed that IL-34 was highly produced by CAFs and to lesser extent by normal fibroblasts isolated from non-tumoral colonic mucosa of CRC patients. CAFs and normal fibroblasts expressed the functional receptors of IL-34. IL-34 induced normal fibroblasts to express α-SMA, vimentin and fibroblast activation protein and enhanced fibroblast growth, thus generating a cellular phenotype resembling that of CAFs. Consistently, knockdown of IL-34 in CAFs with an antisense oligonucleotide (AS) decreased expression of such markers and inhibited cell proliferation. Co-culture of CRC cells with IL-34 AS-treated CAFs supernatants resulted in less cancer cell proliferation and migration. Among CAF-derived molecules known to promote CRC cell growth/migration, only netrin-1 and basic-fibroblast growth factor were induced by IL-34. Data suggest a role for IL-34 in the control of colorectal CAF function.

Targeting Netrin-1 and -4 as a Novel Diagnostic Parameter and Treatment Option for Diabetic Retinopathy

Diabetic retinopathy (DR) is a retinal vascular disorder associated with both type 1 and type 2 diabetes mellitus (DM). It is characterized by specific loss of pericytes, which leads to an augmented blood vessel permeability, and development of new blood vessels (retinal neovascularization). Moreover, stiffening of eye membrane, inflammation, and apoptosis of endothelial cells also lead to damage of the blood-retinal barrier and blindness in most cases unless it's detected and managed early. Hence, this review was intended to assess the potential roles of Netrin-1 and -4 as new/alternative biomarkers and therapeutic options for DR. Netrin-1 and -4 have been the most known ligands and are well known for their role in neural guidance. DR has both neural and vascular components; therefore, biomarkers used for both neural and vascular retinal tissues are potentially important. According to different experimental and clinical studies, as compared to the normal groups, there was a significant increment in both retinal Netrin-1 and -4 mRNA and protein levels in the retinopathy groups. In addition, exogenous supplementation of these proteins is also used as a therapeutic agent for DR.

Plasma Adipsin as a Biomarker and Its Implication in Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is a worldwide health threat affecting millions of people, which is associated with different micro- and macro-vascular complications. Type 2 diabetes mellitus (T2DM) is one of the different types of DM caused by insulin resistance and/or reduced secretion of insulin from the pancreas. A validated novel biomarker is required to enhance the accuracy of disease prediction, provide novel insights into pathophysiology and contribute to future prevention of T2DM. Various newer diagnostic methods have been developed by targeting endogenous proteins among which Adipsin is one of the promising target. Therefore, this review discusses Adipsin as a potential biomarker and its implication in T2DM. Adipsin is one of the adipokines secreted by adipose tissues which is involved in maintaining adipose tissue homeostasis and increasing insulin secretion in response to glucose. According to different experimental and clinical studies, plasma Adipsin concentrations are low in animals and patients with DM which support its use as a biomarker in combination to the other diagnostic modalities for DM. Additionally, the existence of Adipsin could be important in improving hyperglycemia by preserving β-cell mass through improving β-cell survival and maintaining their transcriptional identity.

Potential Effect of Hydroxychloroquine in Diabetes Mellitus: A Systematic Review on Preclinical and Clinical Trial Studies

BACKGROUND

Diabetes mellitus is a chronic metabolic disorder characterized by persistent hyperglycemia. It affects millions of people globally. In spite of many antidiabetic drugs that are available, an adequate level of control remains challenging. Hydroxychloroquine is an immunomodulatory drug that has been used for the treatment of malaria and autoimmune diseases. There is an emerging evidence that suggests its beneficial effect against diabetes mellitus. Therefore, this systematic review is aimed at discoursing the role of hydroxychloroquine against diabetes mellitus and its potential mechanisms of actions.

METHODS

A systematic and manual searching was carried out to retrieve relevant articles (preclinical and clinical studies) published from January 2014 to July 2019. Electronic databases including PubMed and Scopus as well as clinicaltrials.gov have been searched using different searching terms: "hydroxychloroquine," "diabetes mellitus," "hyperglycemia," and "insulin resistance." The MeSH terms (PubMed) and text words were combined with "AND" or "OR." In addition, manual searching of Google Engine and Google Scholar was conducted. Quality assessment of all the included studies was performed using CAMARADES (preclinical studies) and the Newcastle-Ottawa Scale and Cochrane Collaboration's tools (clinical studies).

RESULTS

A total of eighteen studies (three experimental and fifteen clinical studies) were found to be eligible for the present systematic review. Among the included clinical studies (six randomized control trials, five observational studies, and four cohort studies), about 55,776 study participants were involved. Most of these studies showed significant improvement of lipid profile and insulin levels and substantial diminution of hemoglobin A1c, fasting plasma glucose, and postprandial blood glucose levels. Reduction in lysosomal degradation of the internal insulin-insulin receptor complex and enhancement in insulin sensitivity and adiponectin levels are some of the hypothesized mechanisms for the antidiabetic effect of hydroxychloroquine.

CONCLUSION

The current review provides preliminary evidence for potential antidiabetic properties of hydroxychloroquine. Though the provided available data were promising, further clinical trials and mechanistic studies are needed to determine its long-term effects.

Biomarkers in Stress Related Diseases/Disorders: Diagnostic, Prognostic, and Therapeutic Values

Various internal and external factors negatively affect the homeostatic equilibrium of organisms at the molecular to the whole-body level, inducing the so-called state of stress. Stress affects an organism's welfare status and induces energy-consuming mechanisms to combat the subsequent ill effects; thus, the individual may be immunocompromised, making them vulnerable to pathogens. The information presented here has been extensively reviewed, compiled, and analyzed from authenticated published resources available on Medline, PubMed, PubMed Central, Science Direct, and other scientific databases. Stress levels can be monitored by the quantitative and qualitative measurement of biomarkers. Potential markers of stress include thermal stress markers, such as heat shock proteins (HSPs), innate immune markers, such as Acute Phase Proteins (APPs), oxidative stress markers, and chemical secretions in the saliva and urine. In addition, stress biomarkers also play critical roles in the prognosis of stress-related diseases and disorders, and therapy guidance. Moreover, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be employed to evaluate these conditions precisely, but with stringent validation and specificity. Considerable scientific advances have been made in the detection, quantitation, and application of these biomarkers. The present review describes the current progress of identifying biomarkers, their prognostic, and therapeutic values.

Biomarkers in Stress Related Diseases/Disorders: Diagnostic, Prognostic, and Therapeutic Values

Various internal and external factors negatively affect the homeostatic equilibrium of organisms at the molecular to the whole-body level, inducing the so-called state of stress. Stress affects an organism's welfare status and induces energy-consuming mechanisms to combat the subsequent ill effects; thus, the individual may be immunocompromised, making them vulnerable to pathogens. The information presented here has been extensively reviewed, compiled, and analyzed from authenticated published resources available on Medline, PubMed, PubMed Central, Science Direct, and other scientific databases. Stress levels can be monitored by the quantitative and qualitative measurement of biomarkers. Potential markers of stress include thermal stress markers, such as heat shock proteins (HSPs), innate immune markers, such as Acute Phase Proteins (APPs), oxidative stress markers, and chemical secretions in the saliva and urine. In addition, stress biomarkers also play critical roles in the prognosis of stress-related diseases and disorders, and therapy guidance. Moreover, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be employed to evaluate these conditions precisely, but with stringent validation and specificity. Considerable scientific advances have been made in the detection, quantitation, and application of these biomarkers. The present review describes the current progress of identifying biomarkers, their prognostic, and therapeutic values.

Netrin Family: Role for Protein Isoforms in Cancer

Netrins form a family of secreted and membrane-associated proteins. Netrins are involved in processes for axonal guidance, morphogenesis, and angiogenesis by regulating cell migration and survival. These processes are of special interest in tumor biology. From the netrin genes various isoforms are translated and regulated by alternative splicing. We review here the diversity of isoforms of the netrin family members and their known and potential roles in cancer.