The role of progranulin in diabetes and kidney disease

Increased circulating progranulin is not sufficient to induce cardiac dysfunction or supraventricular arrhythmia

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, and the incidence of new-onset AF has been increasing over the past two decades. Several factors contribute to the risk of developing AF including age, preexisting cardiovascular disease, chronic kidney disease, and obesity. Concurrent with the rise in AF, obesity has followed the same two-decade trend. The contribution of circulating proteins to obesity-related AF is of particular interest in the field. In this study, we investigated the effects of increased circulating levels of the glycoprotein progranulin on the development of supraventricular arrhythmias and changes to cardiac function. AAV8-mediated overexpression of full-length mouse progranulin was used to increase plasma protein levels and determine susceptibility to supraventricular arrhythmias and changes in cardiac structure and function. C57Bl/6N mice were subjected to increased circulating levels of progranulin for 20 weeks. Cardiac conduction was evaluated by surface ECG with and without isoproterenol challenge, and cardiac structure and function were measured by echocardiography after 20 weeks of circulating progranulin overexpression. Increased circulating levels of progranulin were maintained throughout the 20-week study. The cardiac structure and function remained unchanged in mice with increased circulating progranulin. ECG indices (P wave duration, P amplitude, QRS interval) were unaffected by increased progranulin levels and no arrhythmogenic events were observed following the isoproterenol challenge. In our model, increased levels of circulating progranulin were not sufficient to induce changes in cardiac structure and function or elicit ECG abnormalities suggestive of susceptibility to supraventricular arrhythmias.

Immunological link between periodontitis and type 2 diabetes deciphered by single-cell RNA analysis

BACKGROUND

Type 2 diabetes mellitus (DM) is a complex metabolic disorder that causes various complications, including periodontitis (PD). Although a bidirectional relationship has been reported between DM and PD, their immunological relationship remains poorly understood. Therefore, this study aimed to compare the immune response in patients with PD alone and in those with both PD and DM (PDDM) to expand our knowledge of the complicated connection between PD and DM.

METHODS

Peripheral blood mononuclear cells were collected from 11 healthy controls, 10 patients with PD without DM, and six patients with PDDM, followed by analysis using single-cell RNA sequencing. The differences among groups were then compared based on intracellular and intercellular perspectives.

RESULTS

Compared to the healthy state, classical monocytes exhibited the highest degree of transcriptional change, with elevated levels of pro-inflammatory cytokines in both PD and PDDM. DM diminished the effector function of CD8+ T and natural killer (NK) cells as well as completely modified the differentiation direction of these cells. Interestingly, a prominent pathway, RESISTIN, which is known to increase insulin resistance and susceptibility to diabetes, was found to be activated under both PD and PDDM conditions. In particular, CAP1+ classical monocytes from patients with PD and PDDM showed elevated nuclear factor kappa B-inducing kinase activity.

CONCLUSIONS

Overall, this study elucidates how the presence of DM contributes to the deterioration of T/NK cell immunity and the immunological basis connecting PD to DM.

Progranulin is an FMRP target that influences macroorchidism but not behaviour in a mouse model of Fragile X Syndrome

A growing body of evidence has implicated progranulin in neurodevelopment and indicated that aberrant progranulin expression may be involved in neurodevelopmental disease. Specifically, increased progranulin expression in the prefrontal cortex has been suggested to be pathologically relevant in male Fmr1 knockout (Fmr1 KO) mice, a mouse model of Fragile X Syndrome (FXS). Further investigation into the role of progranulin in FXS is warranted to determine if therapies that reduce progranulin expression represent a viable strategy for treating patients with FXS. Several key knowledge gaps remain. The mechanism of increased progranulin expression in Fmr1 KO mice is poorly understood and the extent of progranulin's involvement in FXS-like phenotypes in Fmr1 KO mice has been incompletely explored. To this end, we have performed a thorough characterization of progranulin expression in Fmr1 KO mice. We find that the phenomenon of increased progranulin expression is post-translational and tissue-specific. We also demonstrate for the first time an association between progranulin mRNA and FMRP, suggesting that progranulin mRNA is an FMRP target. Subsequently, we show that progranulin over-expression in Fmr1 wild-type mice causes reduced repetitive behaviour engagement in females and mild hyperactivity in males but is largely insufficient to recapitulate FXS-associated behavioural, morphological, and electrophysiological abnormalities. Lastly, we determine that genetic reduction of progranulin expression on an Fmr1 KO background reduces macroorchidism but does not alter other FXS-associated behaviours or biochemical phenotypes.

Serum progranulin as a potential biomarker for frailty in Chinese older adults

BACKGROUND

Frailty can increase adverse health outcomes in older adults. Progranulin is a secreted glycoprotein involved in regulating various biological processes. Different perspectives exist on the relationship between progranulin and frailty.

AIMS

We aimed to evaluate the association of progranulin with frailty in older Chinese adults.

METHODS

We included 265 older in-patients who were divided into the robust (n = 31), pre-frail (n = 116) and frail (n = 118) groups according to the FRAIL scale. Serum IL-6, CXCL-10, progranulin, and CRP levels were assayed. Spearman's correlation and logistic regression models were used to analyze the association of serum biomarkers with frailty, and ROC was used to evaluate the diagnostic progranulin value for frailty.

RESULTS

The frail group was older and had lower BMI, higher prevalence of coronary heart disease, worse grip strength and walking speed, and higher IL-6, CXCL-10, progranulin, and CRP serum levels than the robust and pre-frail groups. Progranulin levels were negatively correlated with grip strength (r = - 0.152, p = 0.016) and positively correlated with IL-6 (r = 0.207, p = 0.001) and CXCL-10 (r = 0.160, p = 0.009) after adjusting for age and sex. Furthermore, progranulin remained associated with frailty after adjusting for age, sex, BMI, smoking, chronic diseases, and pro-inflammatory cytokines (OR = 1.003, 95% CI 1.001-1.006, p = 0.022). The AUC of serum progranulin levels for diagnostic frailty was 0.927 (95% CI 0.896-0.958, p < 0.001).

CONCLUSION

High serum progranulin levels were observed in frail older adults and were associated with worse physical function and increased chronic inflammation. Progranulin may be a potential biomarker for frailty.

Progranulin, a moderator of estrogen/estrogen receptor α binding, regulates bone homeostasis through PERK/p-eIF2 signaling pathway

Under normal conditions, the human body employs the synergistic action of osteoblasts and osteoclasts to maintain a dynamic balance between bone formation and resorption. Bone homeostasis plays a very important role in the process of bone formation. Various bone diseases can occur if bone homeostasis is disrupted. In this study, the serum estrogen levels were significantly increased in the granulin (GRN)-deficient mice and PGRN regulates the binding of estrogen and estrogen receptor α (ERα) and then affects estrogen's ability to regulate bone formation and resorption. In addition, this study also explored the role that PGRN plays in regulating bone homeostasis by affecting the binding of estrogen and estrogen receptors through the protein kinase R-like endoplasmic reticulum kinase/phosphorylation of the eukaryotic initiation factor 2 signaling pathway. In summary, we confirmed the important role of PGRN in regulating the estrogen (E2)/ERα signal in maintaining bone homeostasis. Our findings may provide a new strategy for the treatment of osteoporosis and maintaining bone homeostasis. KEY MESSAGES: PGRN is a molecular regulator of the binding of E2 and ERα signal in maintaining bone homeostasis. PGRN plays in regulating bone homeostasis through the PERK/p-eIF2α signaling pathway. The best therapeutic effect of PGRN in osteoporosis is associated with different concentration of E2.

Progranulin Preserves Autophagy Flux and Mitochondrial Function in Rat Cortical Neurons Under High Glucose Stress

Chronic hyperglycemia in type II diabetes results in impaired autophagy function, accumulation of protein aggregates, and neurodegeneration. However, little is known about how to preserve autophagy function under hyperglycemic conditions. In this study, we tested whether progranulin (PGRN), a neurotrophic factor required for proper lysosome function, can restore autophagy function in neurons under high-glucose stress. We cultured primary cortical neurons derived from E18 Sprague-Dawley rat pups to maturity at 10 days in vitro (DIV) before incubation in high glucose medium and PGRN for 24-72 h before testing for autophagy flux, protein turnover, and mitochondrial function. We found that although PGRN by itself did not upregulate autophagy, it attenuated impairments in autophagy seen under high-glucose conditions. Additionally, buildup of the autophagosome marker light chain 3B (LC3B) and lysosome marker lysosome-associated membrane protein 2A (LAMP2A) changed in both neurons and astrocytes, indicating a possible role for glia in autophagy flux. Protein turnover, assessed by remaining advanced glycation end-product levels after a 6-h incubation, was preserved with PGRN treatment. Mitochondrial activity differed by complex, although PGRN appeared to increase overall activity in high glucose. We also found that activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and glycogen synthase kinase 3β (GSK3β), kinases implicated in autophagy function, increased with PGRN treatment under stress. Together, our data suggest that PGRN prevents hyperglycemia-induced decreases in autophagy by increasing autophagy flux via increased ERK1/2 kinase activity in primary rat cortical neurons.

Association of Progranulin Gene Expression from Dyspeptic Patients with Virulent Helicobacter pylori Strains; In Vivo Model

(1) Background: Gastric cancer, the fourth most common cause of death from tumors in the world, is closely associated with Helicobacter pylori. Timely diagnosis, therefore, is essential to achieve a higher survival rate. In Chile, deaths from gastric cancer are high, mainly due to late diagnosis. Progranulin has reflected the evolution of some cancers, but has been poorly studied in gastric lesions. Aiming to understand the role of progranulin in H. pylori infection and its evolution in development of gastric lesions, we evaluated the genic expression of progranulin in gastric tissue from infected and non-infected patients, comparing it according to the epithelial status and virulence of H. pylori strains. (2) Methods: The genic expression of progranulin by q-PCR was quantified in gastric biopsies from Chilean dyspeptic patients (n = 75) and individuals who were uninfected (n = 75) by H. pylori, after receiving prior informed consent. Bacteria were grown on a medium Columbia agar with equine-blood 7%, antibiotics (Dent 2%, Oxoid^TM), in a microaerophilic environment, and genetically characterized for the ureC, vacA, cagA, and iceA genes by PCR. The status of the tissue was determined by endoscopic observation. (3) Results: Minor progranulin expression was detected in atrophic tissue, with a sharp drop in the tissue colonized by H. pylori that carried greater virulence, VacAs1m1⁺CagA⁺IceA1⁺. (4) Conclusions: Progranulin shows a differential behavior according to the lesions and virulence of H. pylori, affecting the response of progranulin against gastric inflammation.

Effects of alpha-lipoic acid treatment on serum progranulin levels and inflammatory markers in diabetic neuropathy

Objectives

Progranulin (PGRN) is a secreted growth factor that helps to regulate neuronal survival by blocking tumor necrosis factor-alpha (TNFα) receptors. The antioxidant alpha-lipoic acid (ALA) is used in diabetic neuropathy to improve nerve conduction and relieve neuropathic pain, but its effects on PGRN levels have not yet been elucidated.

Methods

In this prospective study, 54 patients with type 2 diabetes and peripheral neuropathy received 600 mg of ALA daily for 6 months. Twenty-four patients with diabetes without neuropathy were also included in the study. Serum PGRN and TNFα levels were determined using enzyme-linked immunosorbent assays. In addition, current perception threshold (CPT) testing was used to assess sensory neuropathy.

Results

After ALA treatment, serum PGRN levels were significantly increased and CPT values were significantly improved. Furthermore, there were significant positive correlations among TNFα, ICAM-1, and PGRN levels both before and after ALA treatment. A significant negative correlation was observed between the improvements in CPT and the PGRN levels. Furthermore, ICAM-1 levels were an independent predictor of PGRN levels.

Conclusions

Changes in serum PGRN levels indicate that ALA treatment may have beneficial effects on endothelial function and neuronal inflammation.

Cardio- and Neurometabolic Adipobiology: Consequences and Implications for Therapy

Studies over the past 30 years have revealed that adipose tissue is the major endocrine and paracrine organ of the human body. Arguably, adiopobiology has taken its reasonable place in studying obesity and related cardiometabolic diseases (CMDs), including Alzheimer's disease (AD), which is viewed herein as a neurometabolic disorder. The pathogenesis and therapy of these diseases are multiplex at basic, clinical and translational levels. Our present goal is to describe new developments in cardiometabolic and neurometabolic adipobiology. Accordingly, we focus on adipose- and/or skeletal muscle-derived signaling proteins (adipsin, adiponectin, nerve growth factor, brain-derived neuroptrophic factor, neurotrophin-3, irisin, sirtuins, Klotho, neprilysin, follistatin-like protein-1, meteorin-like (metrnl), as well as growth differentiation factor 11) as examples of metabotrophic factors (MTFs) implicated in the pathogenesis and therapy of obesity and related CMDs. We argue that these pathologies are MTF-deficient diseases. In 1993 the "vascular hypothesis of AD" was published and in the present review we propose the "vasculometabolic hypothesis of AD." We discuss how MTFs could bridge CMDs and neurodegenerative diseases, such as AD. Greater insights on how to manage the MTF network would provide benefits to the quality of human life.

Human progranulin-expressing mice as a novel tool for the development of progranulin-modulating therapeutics

The granulin protein (also known as, and hereafter referred to as, progranulin) is a secreted glycoprotein that contributes to overall brain health. Heterozygous loss-of-function mutations in the gene encoding the progranulin protein (Granulin Precursor, GRN) are a common cause of familial frontotemporal dementia (FTD). Gene therapy approaches that aim to increase progranulin expression from a single wild-type allele, an area of active investigation for the potential treatment of GRN-dependent FTD, will benefit from the availability of a mouse model that expresses a genomic copy of the human GRN gene. Here we report the development and characterization of a novel mouse model that expresses the entire human GRN gene in its native genomic context as a single copy inserted into a defined locus (Hprt) in the mouse genome. We show that human and mouse progranulin are expressed in a similar tissue-specific pattern, suggesting that the two genes are regulated by similar mechanisms. Human progranulin rescues a phenotype characteristic of progranulin-null mice, the exaggerated and early deposition of the aging pigment lipofuscin in the brain, indicating that the two proteins are functionally similar. Longitudinal behavioural and neuropathological analyses revealed no significant differences between wild-type and human progranulin-overexpressing mice up to 18 months of age, providing evidence that long-term increase of progranulin levels is well tolerated in mice. Finally, we demonstrate that human progranulin expression can be increased in the brain using an antisense oligonucleotide that inhibits a known GRN-regulating micro-RNA, demonstrating that the transgene is responsive to potential gene therapy drugs. Human progranulin-expressing mice represent a novel and valuable tool to expedite the development of progranulin-modulating therapeutics.

Differential organ-specific inflammatory response to progranulin in high-fat diet-fed mice

Progranulin (PGRN) has been reported to bind tumor necrosis factor (TNF) receptor and to inhibit TNFα signaling. We evaluated the effect of augmentation of TNFα signaling by PGRN deficiency on the progression of kidney injury. Eight-week-old PGRN knockout (KO) and wild-type (WT) mice were fed a standard diet or high-fat diet (HFD) for 12 weeks. Albuminuria, markers of tubular damage, and renal mRNA levels of inflammatory cytokines were higher in HFD-fed KO (KO-HFD) mice than in HFD-fed WT (WT-HFD) mice. Body weight, vacuolization in proximal tubules, and systemic and adipose tissue inflammatory markers were lower in the KO-HFD mice than in the WT-HFD mice. The renal megalin expression was lower in the KO mice than in the WT mice regardless of the diet type. The megalin expression was also reduced in mouse proximal tubule epithelial cells stimulated with TNFα and in those with PGRN knockdown by small interfering RNA in vitro. PGRN deficiency was associated with both exacerbated renal inflammation and decreased systemic inflammation, including that in the adipose tissue of mice with HFD-induced obesity. Improved tubular vacuolization in the KO-HFD mice might partially be explained by the decreased expression of megalin in proximal tubules.

Plasma progranulin levels in obese patients before and after Roux-en-Y gastric bariatric surgery: a longitudinal study

BACKGROUND

Bariatric surgery stands out as the most effective long-term intervention for sustainable weight loss and metabolic improvement in patients with severe obesity. Progranulin was recently identified as an adipokine related to obesity and inflammation, revealing a metabolic function and proinflammatory properties.

OBJECTIVE

To evaluate plasma progranulin levels before and after 6 months of bariatric surgery in Roux-en-Y gastric bypass (RYGB).

SETTING

Tertiary referral hospital, southern Brazil.

METHODS

This was a prospective longitudinal study, including 23 obese patients who underwent RYGB. Demographic and clinical characteristics, body composition, and resting energy expenditure were evaluated. Plasma progranulin was determined with enzyme-linked immunosorbent assays in a peripheral blood sample collected before and 6 months after the surgical procedure.

RESULTS

The participants were mostly women (78.3%), with a mean age of 42.3 ± 10.8 years and baseline body mass index of 48.8 ± 10.4 kg/m². Regarding the anthropometric parameters, there were differences in the pre- and post-RYGB values, with reduction of weight, body mass index, body fat percentage, and cervical and abdominal circumferences. All laboratory parameters improved, such as lipid profile and fasting glycemia, and resting energy expenditure values decreased significantly. Plasma progranulin levels decreased from 47.6 ± 13.5 ng/mL before RYGB to 40.4 ± 9.9 ng/mL after 6 months of surgery (P = .005). The reduction of progranulin did not correlate with body composition or laboratory data.

CONCLUSIONS

Plasma progranulin levels significantly reduced 6 months after RYGB, but it could not be explained by changes in anthropometry, body composition, or glycemic or lipid profile.

Remodeling adipose tissue inflammasome for type 2 diabetes mellitus treatment: Current perspective and translational strategies

Obesity-associated type 2 diabetes mellitus (T2DM) is characterized by low-grade chronic systemic inflammation that arises primarily from the white adipose tissue. The interplay between various adipose tissue-derived chemokines drives insulin resistance in T2DM and has therefore become a subject of rigorous investigation. The adipocytokines strongly associated with glucose homeostasis include tumor necrosis factor-α, various interleukins, monocyte chemoattractant protein-1, adiponectin, and leptin, among others. Remodeling the adipose tissue inflammasome in obesity-associated T2DM is likely to treat the underlying cause of the disease and bring significant therapeutic benefit. Various strategies have been adopted or are being investigated to modulate the serum/tissue levels of pro- and anti-inflammatory adipocytokines to improve glucose homeostasis in T2DM. These include use of small molecule agonists/inhibitors, mimetics, antibodies, gene therapy, and other novel formulations. Here, we discuss adipocytokines that are strongly associated with insulin activity and therapies that are under investigation for modulation of their levels in the treatment of T2DM.

The effects of circuit resistance training on plasma progranulin level, insulin resistance and body composition in obese men

Background Progranulin (PGRN) is implicated in obesity and insulin resistance (IR). The aim of this study was to evaluate the effects of 8 weeks of circuit resistance training (CRT) on plasma PGRN, IR and body composition in obese men. Materials and methods Twenty-eight healthy obese men [age: 36 ± 7.7 years, body weight (BW): 96.4 ± 15.6 kg, body mass index (BMI): 32.4 ± 4.5 kg/m2] completed the study. Subjects were randomly assigned to two groups of control and training. Subjects in the training group underwent training for 8 weeks, 3 times a week. Blood samples and anthropometric characteristics were taken before the commencement of the exercise protocol and 72 h after the last training session. The homeostatic model assessment of insulin resistance (HOMA-IR) was used to measure IR. Results BW, BF%, BMI, waist-hip ratio (WHR), HOMA-IR and plasma PGRN levels except lean body mass (LBM) were significantly reduced in the training group (p < 0.05). Additionally, except for LBM, subjects in the training group had significantly decreased BW, BF%, BMI, WHR, HOMA-IR and plasma PGRN levels compared to changes in those in the control group (p < 0.05). Significant correlations were found between the changes in plasma PGRN and the changes in insulin, HOMA-IR and BMI (p < 0.05). Conclusions The findings showed that 8 weeks of CRT improved body composition and IR which were accompanied by reduced plasma PGRN levels. This study suggests that CRT has the potential for obese individuals to counteract obesity-associated health impairments.

Progranulin attenuates liver fibrosis by downregulating the inflammatory response

Progranulin (PGRN) is a cysteine-rich secreted protein expressed in endothelial cells, immune cells, neurons, and adipocytes. It was first identified for its growth factor-like properties, being implicated in tissue remodeling, development, inflammation, and protein homeostasis. However, these findings are controversial, and the role of PGRN in liver disease remains unknown. In the current study, we examined the effect of PGRN in two different models of chronic liver disease, methionine‐choline‐deficient diet (MCD)-induced non-alcoholic steatohepatitis (NASH) and carbon tetrachloride (CCl4)-induced liver fibrosis. To induce long-term expression of PGRN, PGRN-expressing adenovirus was delivered via injection into the tibialis anterior. In the CCl4-induced fibrosis model, PGRN showed protective effects against hepatic injury, inflammation, and fibrosis via inhibition of nuclear transcription factor kappa B (NF-κB) phosphorylation. PGRN also decreased lipid accumulation and inhibited pro-inflammatory cytokine production and fibrosis in the MCD-induced NASH model. In vitro treatment of primary macrophages and Raw 264.7 cells with conditioned media from hepatocytes pre-treated with PGRN prior to stimulation with tumor necrosis factor (TNF)-α or palmitate decreased their expression of pro-inflammatory genes. Furthermore, PGRN suppressed inflammatory and fibrotic gene expression in a cell culture model of hepatocyte injury and primary stellate cell activation. These observations increase our understanding of the role of PGRN in liver injury and suggest PGRN delivery as a potential therapeutic strategy in chronic inflammatory liver disease.

Probiotic Soy Milk Consumption and Renal Function Among Type 2 Diabetic Patients with Nephropathy: a Randomized Controlled Clinical Trial

Diabetic nephropathy (DN) is one the most important complications of diabetes leading to end-stage renal disease. Dietary approaches have been considered to control of the kidney function deterioration among these patients. The aim of the present study was to determine the effects of fortified soy milk with Lactobacillus plantarum A7 on renal function biomarkers in type 2 DN patients. Forty-eight DN subjects were attended to this parallel randomized trial study. Participants were randomly assigned to consume a diet containing 200 mL/day probiotic soy milk in intervention group or soy milk in the control condition for 8 weeks. An inflammatory adipokine-Progranulin (PGRN), a cytokine receptor-soluble tumor necrosis factor receptor 1 (sTNFR1), and serum levels of Neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C (Cys-C) as the new renal function biomarkers were measured after 8 weeks of intervention according to the standard protocol. Our analysis showed that consumption of probiotic soy milk resulted in a significant reduction in the Cys-C and PGRN levels compared with the soy milk (P = 0.01) in the final adjusted model. In addition, after adjustment for age, weight, and energy intake, a marginally significant in the NGAL level was seen between two groups (P = 0.05). However, there was no significant differences on the sTNFR1concenteration between two groups (P = 0.06). Overall, intake of probiotic soy milk may have a beneficial effect on the renal function in patients with DN.

PGRN acts as a novel regulator of mitochondrial homeostasis by facilitating mitophagy and mitochondrial biogenesis to prevent podocyte injury in diabetic nephropathy

Mitochondrial dysfunction is considered as a key mediator in the pathogenesis of diabetic nephropathy (DN). Therapeutic strategies targeting mitochondrial dysfunction hold considerable promise for the treatment of DN. In this study, we investigated the role of progranulin (PGRN), a secreted glycoprotein, in mediating mitochondrial homeostasis and its therapeutic potential in DN. We found that the level of PGRN was significantly reduced in the kidney from STZ-induced diabetic mice and patients with biopsy-proven DN compared with healthy controls. In DN model, PGRN-deficient mice aggravated podocyte injury and proteinuria versus wild-type mice. Functionally, PGRN deficiency exacerbated mitochondrial damage and dysfunction in podocytes from diabetic mice. In vitro, treatment with recombinant human PGRN (rPGRN) attenuated high glucose-induced mitochondrial dysfunction in podocytes accompanied by enhanced mitochondrial biogenesis and mitophagy. Inhibition of mitophagy disturbed the protective effects of PGRN in high glucose-induced podocytotoxicity. Mechanistically, we demonstrated that PGRN maintained mitochondrial homeostasis via PGRN-Sirt1-PGC-1α/FoxO1 signaling-mediated mitochondrial biogenesis and mitophagy. Finally, we provided direct evidence for therapeutic potential of PGRN in mice with DN. This study provides new insights into the novel role of PGRN in maintaining mitochondrial homeostasis, suggesting that PGRN may be an innovative therapeutic strategy for treating patients with DN.

Potential value of serum Progranulin as a biomarker for the presence and severity of micro vascular complications among Egyptian patients with type 2 diabetes mellitus

Objective

The increasing prevalence of type 2 diabetes mellitus (T2DM) calls for evolving a concomitant screening strategies for early disease detection and prediction of the complications. Progranulin (PRGN) was recently introduced as a biomarker of inflammation in T2DM. However, little data have been published as regarding progranulin in relation to diabetic micro angiopathy among Egyptian patients with T2DM. The aim of this study was therefore to investigate and evaluate serum progranulin as a biomarker for the presence and severity of micro vascular complications among Egyptian patients with T2DM.

Methods

A total of 90 age and sex matched participants were included in this cross sectional study. They were divided into group 1 included 30 non diabetic healthy controls and group 2 included 60 patients with type 2 diabetes mellitus. Furthermore, diabetic patients were categorized into two subgroups depending on the presence or absence of microvascular complications. Evaluation for diabetic nephropathy, neuropathy and retinopathy were determined. Furthermore, laboratory investigations were performed and serum progranulin levels were measured by a quantitative sandwich enzyme linked immune sorbent assay.

Results

The mean serum PRGN levels were significantly elevated in type 2 diabetic patients (20.90 ± 6.38 ng/ml) compared to control group (9.20 ± 1.41 ng/ml) (p < 0.001). Moreover,the serum PRGN levels were increased parallel to the severity of diabetic nephropathy (DN) and diabetic retinopathy (DR) with significantly highest detectable values were in macro albuminuric group of diabetic nephropathy as well as proliferative diabetic retinopathy (PDR) groups (P < 0.001). Besides, it worth mentioning that, the level of Serum progranulin started to increase significantly in stage 2 DN in spite of normal level of albuminuria. There were highly significant positive correlation between serum PRGN and disease duration, body mass index (BMI),fasting blood sugar (FBS), HbA1c, Total cholesterol (TC),triglyceride (TG), serum creatinine, ACR (r = 0.918, 0.623, 0.430, 0.539,0.910,0.842,0.759, 0.903, resp., P < 0.001) and a significant positive correlation with low density lipoprotein (LDL) (r = 0.344),but there was a highly significant negative correlation between serum PRGN and eGFR (r = -0.866, P < 0.001) in the studied diabetic patients.

Conclusion

Progranulin might be considered as a biomarker for diabetic micro angiopathy and its severity. In addition, there is a group of diabetic patients with decreased eGFR but without albuminuria in which serum PRGN level was indicated to be used as an early biomarker of diabetic nephropathy.

The association between dietary antioxidants and adipokines level among obese women

AIM

Adipokines are associated with several oxidative stress-related diseases and pathologic conditions. We aimed to assess the association between antioxidants and adipokines in obese adults.

METHODS AND MATERIALS

In this cross-sectional study, a total of 160 obese women were included. Body composition and anthropometric characteristics were measured. Dietary intakes were assessed by 3-day, 24-h dietary recall. Blood samples were obtained following an overnight fasting. Serum concentrations of adipokines including progranulin, retinol binding protein 4 (RBP4) and Angiopoietin-related growth factor 6 (ANGPTL6) was measured using an enzyme-linked immunosorbent assay. ANCOVA and the linear regression model analysis was performed to assess the relationship between Progranulin, RBP4, AnGPTL6, and antioxidants.

RESULTS

Mean age of included women was 39.31 ± 12.10. Mean and standard deviation for BMI was 35.05 ± 4.26 in this obese population. There was a positive significant association between ANGPTL6 and vitamin D intake (p < 0.001). Also, there was a marginal association between RBP4 and vitamin A (p = 0.063) intake, but after adjustment age, and fat mass, we found a significant association (p = 0.008). However, the associations between dietary antioxidants, progranulin, and ANGPTL6 were not statistically significant.

CONCLUSIONS

ANGPTL6 and RBP4 levels directly associated with dietary vitamins D and A intake, respectively. But, according to the results, the association between ANGPTL6 and vitamin D was bidirectional. The suggested associations probably can be useful in the development of interventional studies for management of chronic diseases.

Association between circulating tumor necrosis factor-related biomarkers and estimated glomerular filtration rate in type 2 diabetes

Chronic inflammation plays a crucial role in the development/progression of diabetic kidney disease. The involvement of tumor necrosis factor (TNF)-related biomarkers [TNFα, progranulin (PGRN), TNF receptors (TNFR1 and TNFR2)] and uric acid (UA) in renal function decline was investigated in patients with type 2 diabetes (T2D). Serum TNF-related biomarkers and UA levels were measured in 594 Japanese patients with T2D and an eGFR ≥30 mL/min/1.73 m². Four TNF-related biomarkers and UA were negatively associated with estimated glomerular filtration rate (eGFR). In a logistic multivariate model, each TNF-related biomarker and UA was associated with lower eGFR (eGFR <60mL /min/1.73 m²) after adjustment for relevant covariates (basic model). Furthermore, UA and TNF-related biomarkers other than PGRN added a significant benefit for the risk factors of lower eGFR when measured together with a basic model (UA, ΔAUC, 0.049, p < 0.001; TNFα, ΔAUC, 0.022, p = 0.007; TNFR1, ΔAUC, 0.064, p < 0.001; TNFR2, ΔAUC, 0.052, p < 0.001) in receiver operating characteristic curve analysis. TNFR ligands were associated with lower eGFR, but the associations were not as strong as those with TNFRs or UA in patients with T2D and an eGFR ≥30 mL/min/1.73 m².

Circulating PGRN Levels Are Increased but Not Associated with Insulin Sensitivity or β-Cell Function in Chinese Obese Children

Progranulin (PGRN), a novel peptide that has recently emerged as an important regulatory adipokine, is relevant to energy homeostasis and obesity in animals and adult humans. Little is known about its roles in children. The aim of the current study was to determine the potential role of PGRN and explore its relationship to various obesity-related markers in obese children. This was a cross-sectional study composed of 77 children (43 obese and 34 healthy, age 8.68 ± 0.28 and 8.46 ± 0.45 years, resp.). The PGRN levels were significantly higher in obese children (102.44 ± 4.18 ng/mL) comparing to controls (69.32 ± 5.49 ng/mL) (P < 0.05). Moreover, the PGRN levels were positively correlated with triglyceride (TG), total cholesterol (TC), IL-6, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in obese children after adjusted for BMI and age. However, there was no correlation of serum PGRN levels with OGTT-derived dynamic parameters, HOMA-IR, or HOMA-β in obese children. The results suggest that serum PGRN levels are significantly higher in obese children in China and correlate significantly with obesity-related markers. Increased PGRN levels may be involved in the pathological mechanism of childhood obesity.

Association between progranulin serum levels and dietary intake

INTRODUCTION

Progranulin (PGRN) is secreted by adipose tissue and has been linked to obesity, insulin resistance and type 2 diabetes mellitus. There is evidence that a high fat diet increases PGRN expression in rodent adipose tissue. In humans, the relationship between diet composition and concentration of PGRN is still unknown.

OBJECTIVE

To investigate the association between dietary intake and serum PGRN levels.

METHODS

This is an exploratory cross-sectional study including 85 subjects. Demographic, clinical, laboratory and anthropometric data were collected. Serum PGRN was determined by enzyme-linked immunosorbent assay after overnight fasting. Dietary intake was assessed by food frequency questionnaire validated for Brazilian southern population. Focused principal component analyses (FPCA) was used to verify the association of dietary components and food groups with PGRN levels. Sensitivity analyses were performed including only subjects with reporting according to the Goldberg and Black cut-offs of energy intake-energy expenditure ratio between 0.76 and 1.24.

RESULTS

The median PGRN was 51.96 (42.18 to 68.30) ng/mL. Analyzing all sample, the FPCA showed no association of serum PGRN with total energy, protein, carbohydrate, fat and its types, fiber intake and dietary glycemic index; but a significant and positive association between solid fats and PGRN levels (p<0.05). Including only subjects with reporting according cut-off of energy intake-energy expenditure ratio between 0.76 and 1.24, FCPA showed significant and positive association of serum PGRN with saturated fatty acids and solid fats intake (p<0.05). In this subgroup, PGRN correlated with saturated fatty acids (r = 0.341; p = 0.031). Solid fats intake was independently associated to serum PGRN (beta = 0.294; p = 0.004) in multivariate model.

CONCLUSION

The dietary intake of solid fats, mainly represented by saturated fatty acids, is associated to serum PGRN concentration in human subjects.

Adipocytokine Regulation and Antiangiogenic Activity Underlie the Molecular Mechanisms of Therapeutic Effects of Phyllanthus niruri against Non-Alcoholic Fatty Liver Disease

The growth of adipose tissues is considered angiogenesis-dependent during non-alcoholic fatty liver disease (NAFLD). We have recently reported that our standardized 50% methanolic extract (ME) of Phyllanthus niruri (50% ME of P. niruri) has alleviated NAFLD in Sprague⁻Dawley rats. This study aimed to assess the molecular mechanisms of action, and to further evaluate the antiangiogenic effect of this extract. NAFLD was induced by eight weeks of high-fat diet, and treatment was applied for four weeks. Antiangiogenic activity was assessed by aortic ring assay and by in vitro tests. Our findings demonstrated that the therapeutic effects of 50% ME among NAFLD rats, were associated with a significant increase in serum adiponectin, reduction in the serum levels of RBP4, vaspin, progranulin, TNF-α, IL-6, and significant downregulation of the hepatic gene expression of PPARγ, SLC10A2, and Collα1. Concomitantly, 50% ME of P. niruri has exhibited a potent antiangiogenic activity on ring assay, cell migration, vascular endothelial growth factor (VEGF), and tube formation, without any cytotoxic effect. Together, our findings revealed that the protective effects of P. niruri against NAFLD might be attributed to its antiangiogenic effect, as well as to the regulation of adipocytokines and reducing the expression of adipogenic genes.

The complex effects of adipokines in the patients with kidney disease

Kidney diseases are categorized as the highest prevalent ones with worldwide noticeable incidence. They cause accelerated cardiovascular diseases and noticeable mortalities. Adipose tissue and its messengers, adipokines, are reported to have the highest relationship with end-stage renal diseases or chronic kidney diseases. Over recent years, with shifting of scientists’ mindset from a simple overview of adipose tissue as a fat store to the complex paradigm of this issue as a multipotential secretory organ, the importance of studies on this tissue has emerged.

Adipokines in Semen: Physiopathology and Effects on Spermatozoas

Adipokines are secreted by adipose tissue and could be the link between obesity and infertility. Different studies investigated the involvement of adipokines in reproductive functions but only a few have looked into the male part. This review assesses adipokine functions on male reproductive parameters. Adiponectin seems to have a positive effect on sperm parameters, whereas other adipokines such as resistin or chemerin would have a rather deleterious effect on spermatogenesis. Semen parameters seem to be impacted when resistin and chemerin are increased: indeed, there is a decrease of sperm motility. Sperm morphology is improved when adiponectin is increased. The most studied adipokine, leptin, has a dual effect with a positive effect on sperm at physiological levels and a negative one for high seminal concentrations. Many semen parameters and fertility itself are disturbed according to semen adipokine levels, even if it is not the only interfering element. Taken together, adipokines are found in human and animal semen and most of them or their receptors are expressed in male genital tract. Although the pathophysiological role of adipokines in semen is not clearly elucidated, the adipokines could influence sperm functionality and could be potential biomarkers of male fertility.

Progranulin serum levels in human kidney transplant recipients: A longitudinal study

BACKGROUND

The adipokine progranulin has metabolic proprieties, playing a role in obesity and insulin resistance. Its levels seems to be dependent of renal function, since higher progranulin concentration is observed in patients with end-stage kidney disease. However, the effect of kidney transplantation on progranulin remains unknown.

OBJECTIVE

To assess the serum progranulin levels in kidney transplant recipients before and after kidney transplantation.

METHODS

Forty-six prospective kidney transplant recipients were included in this longitudinal study. They were evaluated before transplantation and at three and twelve months after transplantation. Clinical, anthropometric and laboratorial measurements were assessed. Progranulin was determined with enzyme-linked immunosorbent assays.

RESULTS

Serum progranulin significantly decreased in the early period after transplantation (from 72.78 ± 2.86 ng/mL before transplantation to 40.65 ± 1.49 ng/mL at three months; p<0.01) and increased at one year (53.15 ± 2.55 ng/mL; p<0.01 vs. three months), remaining significantly lower than before transplantation (p<0.01) (pover time<0.01). At one year after transplantation, there was a significant increase in body mass index, trunk fat and waist circumference compared to immediate period after transplantation. Progranulin was associated with waist circumference and fasting plasma glucose after adjusted for age, gender, study period, glomerular filtration rate, interleukin-6, high sensitivity C reactive protein and adiponectin.

CONCLUSION

Progranulin serum levels are increased before transplantation and a reduction is observed in the early period after transplantation, possibly attributed to an improvement in renal function. At one year after transplantation, an increment in progranulin is observed, seems to be independent of glomerular filtration, and remained significantly lower than before transplantation.

PGRN Suppresses Inflammation and Promotes Autophagy in Keratinocytes Through the Wnt/β-Catenin Signaling Pathway

Psoriasis is a chronic, immune-mediated inflammatory skin disease that has a major impact on patients' quality of life. Progranulin (PGRN) is highly expressed in skin diseases and plays an important role in inflammation response and autophagy. However, the function of PGRN in the immune system and autophagy in psoriasis has not been clearly identified and elaborated on. Thus, this study aimed to investigate the role of PGRN on the inflammatory and autophagy process underlying inflammation in HaCaT cells. We showed that PGRN was markedly highly expressed in psoriasis lesions and inflammatory HaCaT cells. Specific silencing of PGRN promoted the production of the inflammatory cytokines IL-1β, IL-6, COX-2, iNOs, and MCP-1. Furthermore, PGRN siRNA promoted autophagy-related gene p62 and suppressed LC3II and Atg7 in HaCaT cells, while overexpression of PGRN showed a contrary effect. Moreover, knockdown of PGRN upregulated the expression levels of β-catenin, cyclin D1, and c-myc proteins. Finally, we demonstrated that IWP-2, an inhibitor of the Wnt/β-catenin signaling pathway, stemmed the pro-inflammatory and anti-autophagy effect of PGRN siRNA in TNF-α-treated HaCaT cells. Collectively, our findings suggest that PGRN is upregulated in psoriasis lesions and that the overexpression of PGRN inhibits the inflammation in keratinocytes induced by TNF-α by negatively regulating the production of inflammatory factors and positively mediating autophagy through the Wnt/β-catenin signaling pathway; this indicated that overexpression of PGRN may be a potential therapeutic option in psoriasis.

Novel adipokines: methodological utility in human obesity research

BACKGROUND

Adipokines could pose a link between adiposity, systemic inflammation and metabolic disease risk. However, it is unclear whether representative biomarkers are methodologically suitable for use in human obesity research.

METHODS

We assessed the intra-individual reproducibility of selected adipokines in a sample of 207, apparently healthy, participants with available biosample collections over a 4-month period. Concentrations of the following adipokines were measured at each sampling time point: fatty-acid binding protein-4 (FABP-4), lipocalin-2, monocyte chemoattractant protein 1 (MCP-1), procalcitonin, progranulin, vaspin and visfatin/Nampt. We calculated intraclass correlation coefficients (ICC) and examined Bland-Altman plots.

RESULTS

The analyses suggested an overall good to excellent biomarker reproducibility over 4 months: FABP-4: ICC=0.73 (95% confidence interval: 0.65, 0.78), lipocalin-2: 0.64 (0.55, 0.71), MCP-1: 0.85 (0.81; 0.89), procalcitonin: 0.78 (0.72, 0.83), progranulin: 0.59 (0.50, 0.68) and vaspin: 0.86 (0.82, 0.89). A good agreement of the repeated measurements was further supported by the Bland-Altman plots. No substantial differences in biomarker performance according to adiposity status could be observed. Reliability of visfatin/Nampt could not be assessed due to a high number of measurements below the lower limit of detection.

CONCLUSION

Results suggest that single measurements of the evaluated adipokines could be used in population-based studies aimed to assess links between obesity, inflammation and metabolic diseases.

Paracrine influence of human perivascular cells on the proliferation of adenocarcinoma alveolar epithelial cells

Understanding the crosstalk mechanisms between perivascular cells (PVCs) and cancer cells might be beneficial in preventing cancer development and metastasis. In this study, we investigated the paracrine influence of PVCs derived from human umbilical cords on the proliferation of lung adenocarcinoma epithelial cells (A549) and erythroleukemia cells (TF-1α and K562) in vitro using Transwell® co-culture systems. PVCs promoted the proliferation of A549 cells without inducing morphological changes, but had no effect on the proliferation of TF-1α and K562 cells. To identify the factors secreted from PVCs, conditioned media harvested from PVC cultures were analyzed by antibody arrays. We identified a set of cytokines, including persephin (PSPN), a neurotrophic factor, and a key regulator of oral squamous cell carcinoma progression. Supplementation with PSPN significantly increased the proliferation of A549 cells. These results suggested that PVCs produced a differential effect on the proliferation of cancer cells in a cell-type dependent manner. Further, secretome analyses of PVCs and the elucidation of the molecular mechanisms could facilitate the discovery of therapeutic target(s) for lung cancer.

Serum and Urinary Progranulin in Diabetic Kidney Disease

Progranulin has been recognized as an adipokine related to obesity, insulin resistance and type 2 diabetes mellitus (T2DM). There are scarce data regarding progranulin and kidney disease, but there are some data linking diabetic kidney disease (DKD) and increased progranulin levels. We aimed to better describe the relationship between serum and urinary progranulin levels and DKD in T2DM. This is a case-control study including four groups of subjects: 1) Advanced DKD cases: T2DM patients with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m²; 2) Albuminuric DKD cases: T2DM patients with urinary albumin excretion (UAE) ≥30 mg/g creatinine and eGFR ≥60 mL/min/1.73m²; 3) Diabetic controls: T2DM patients with UAE <30 mg/g creatinine and eGFR ≥60 mL/min/1.73m²; and 4) Non-diabetic controls: individuals without T2DM. Progranulin was determined by enzyme-linked immunosorbent assay. One hundred and fourteen patients were included (23 advanced DKD cases, 25 albuminuric DKD cases, 40 diabetic controls and 26 non-diabetic controls). Serum progranulin was increased in advanced DKD compared to other groups [70.84 (59.04–83.16) vs. albuminuric cases 57.16 (42.24–67.38), diabetic controls 57.28 (42.08–70.47) and non-diabetic controls 44.54 (41.44–53.32) ng/mL; p<0.001]. Urinary progranulin was decreased in advanced DKD cases compared to albuminuric cases [10.62 (6.30–16.08) vs. 20.94 (12.35–30.22); diabetic controls 14.06 (9.88–20.82) and non-diabetic controls 13.51 (7.94–24.36) ng/mL; p = 0.017]. There was a positive correlation between serum progranulin and body mass index (r = 0.27; p = 0.004), waist circumference (r = 0.25; p = 0.007); body fat percentage (r = 0.20; p = 0.042), high-sensitive C reactive protein (r = 0.35; p<0.001) and interleukin-6 (r = 0.37; p<0.001) and a negative correlation with eGFR (r = -0.22; p = 0.023). Urinary progranulin was positively associated with albuminuria (r = 0.25; p = 0.010). In conclusion, progranulin is affected by a decrease in eGFR, being at a higher concentration in serum and lower in urine of DKD patients with T2DM and eGFR <60 mL/min/1.73m². It is also associated with markers of obesity and inflammation.