Topical ocular administration of DPP-Ⅳ inhibitors:a new approach for treating diabetes-induced retinal neurodegeneration

Retinal neurodegeneration plays a significant role in the pathogenesis of diabetic retinopathy(DR),the leading cause of preventable blindness.In fact,the American Diabetes Association has defined DR as a highly specific neurovascular complication(Solomon et al.,2017).Therefore,it is no longer acceptable to consider DR as merely a microvascular complication.In this regard,the term diabetic retinal disease(DRD)has been proposed as a broader term comprising microangiopathy and neurodegeneration.However,there are currently no treatments available that directly target the neurodegenerative changes of DR.This paper will give new insights into the translational research in this field with particular emphasis on glucagon-like peptide 1/dipeptidyl peptidase IV(GLP-1/DPP-IV)inhibitors.

Hydrogen Sulfide Promotes Adipocyte Differentiation, Hyperplasia, and Hypertrophy

Hydrogen sulfide (H2S) is endogenously produced in adipocytes and fat tissues and stimulates adipogenesis. The integrated pathogenic effects of H2S on the development of obesity and the underlying mechanisms, however, have been unclear. Here, we find that a decreased endogenous H2S level lowered lipid accumulation in mouse adipocytes. Exogenous H2S treatment significantly increased the adipogenesis of primary mouse preadipocytes after six days of adipogenic induction. In the early phase of adipogenesis, H2S increased cell proliferation and prepared cells to go through hyperplasia. After H2S treatment for ten days, preadipocytes exhibited significantly greater cell surface area and diameter, indicating cell hypertrophy. Although it stimulated lipid accumulation and adipogenesis, H2S had no effect on lipolysis. With nutrition overload and high glucose/insulin incubation, H2S further stimulated glucose consumption and deteriorated adipocyte hypertrophy. H2S upregulated hyperplasia genes (CCAAT/enhancer-binding protein (C/EBPβ), cell division cycle 25 (Cdc25), minichromosome maintenance 3 (Mcm3), and cell division cycle 45 (Cdc45)) and cyclin-dependent kinase 2 protein (Cdk2), which regulates cell proliferation. H2S also upregulated the insulin receptor β (Irβ)-activated mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) pathways, leading to adipogenesis. In conclusion, H2S increases adipocyte differentiation, hypertrophy, and hyperplasia, implying that it plays a pathogenic role in obesity disorder.

Neurodegeneration:An early event of diabetic retinopathy

Diabetic retinopathy(DR) has been classically considered to be a microcirculatory disease of the retina caused by the deleterious metabolic effects of hyperglycemia per se and the metabolic pathways triggered by hyperglycemia.However,retinal neurodegeneration is already present before any microcirculatory abnormalities can be detected in ophthalmoscopic examination.In other words,retinal neurodegeneration is an early event in the pathogenesis of DR which predates and participates in the microcirculatory abnormalities that occur in DR.Therefore,the study of the mechanisms that lead to neurodegeneration will be essential to identify new therapeutic targets in the early stages of DR.Elevated levels of glutamate and the overexpression of the renin-angiotensin-system play an essential role in the neurodegenerative process that occurs in diabetic retina.Among neuroprotective factors,pigment epithelial derived factor,somatostatin and erythropoietin seem to be the most relevant and these will be considered in this review.Nevertheless,it should be noted that the balance between neurotoxic and neuroprotective factors rather than levels of neurotoxic factors alone will determine the presence or absence of retinal neurodegeneration in the diabetic eye.New strategies,based on either the delivery of neuroprotective agents or the blockade of neurotoxic factors,are currently being tested in experimental models and in clinical pilot studies.Whether these novel therapies will eventually supplement or prevent the need for laser photocoagulation or vitrectomy awaits the results of additional clinical research.

Dietary advanced glycation end-products aggravate non-alcoholic fatty liver disease

AIM To determine if manipulation of dietary advanced glycation end product(AGE), intake affects nonalcoholic fatty liver disease(NAFLD) progression and whether these effects are mediated via RAGE. METHODS Male C57Bl6 mice were fed a high fat, high fructose, high cholesterol(HFHC) diet for 33 wk and compared with animals on normal chow. A third group were given a HFHC diet that was high in AGEs. Another group was given a HFHC diet that was marinated in vinegar to prevent the formation of AGEs. In a second experiment, RAGE KO animals were fed a HFHC diet or a high AGE HFHC diet and compared with wildtype controls. Hepatic biochemistry, histology, picrosirius red morphometry and hepatic mR NA were determined. RESULTS Long-term consumption of the HFHC diet generated significant steatohepatitis and fibrosis after 33 wk. In this model, hepatic 4-hydroxynonenal content(a marker of chronic oxidative stress), hepatocyte ballooning, picrosirius red staining, α-smooth muscle actin and collagen type 1A gene expression were all significantly increased. Increasing the AGE content of the HFHC diet by baking further increased these markers of liver damage, but this was abrogated by pre-marination in acetic acid. In response to the HFHC diet, RAGE-/-animals developed NASH of similar severity to RAGE+/+ animals but were protected from the additional harmful effects of the high AGE containing diet. Studies in isolated Kupffer cells showed that AGEs increase cell proliferation and oxidative stress, providing a likely mechanism through which these compounds contribute to liver injury. CONCLUSION In the HFHC model of NAFLD, manipulation of dietary AGEs modulates liver injury, inflammation, and liver fibrosis via a RAGE dependent pathway. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD.

Mechanisms of retinal neuroprotection of calcium dobesilate：therapeutic implications

Current treatments for diabetic retinopathy （DR） are based on laser photocoagulation and intravitreal injections of corti- costeroids or anti-vascular endothelial growth factor （VEGF） agents. These treatments are applicable only at advanced stages of the disease. In addition, they are expensive, require a vitreo- retinal specialist and are associated with significant adverse ef- fects. Therefore, new pharmacological treatments for the early stages of the disease are needed.

Pharmacological inhibition of diacylglycerol acyltransferase-1 and insights into postprandial gut peptide secretion

AIM To examine the role that enzyme Acyl-CoA:diacylglycerol acyltransferase-1(DGAT1) plays in postprandial gut peptide secretion and signaling.METHODS The standard experimental paradigm utilized to evaluate the incretin response was a lipid challenge.Following a lipid challenge,plasma was collected via cardiac puncture at each time point from a cohort of 5-8 mice per group from baseline at time zero to 10 h.Incretin hormones [glucagon like peptide-1(GLP-1),peptide tyrosine-tyrosine(PYY) and glucose dependent insulinotropic polypeptide(GIP)] were then quantitated.The impact of pharmacological inhibition of DGAT1 on the incretin effect was evaluated in WT mice.Additionally,a comparison of loss of DGAT1 function either by genetic ablation or pharmacological inhibition.To further elucidate the pathways and mechanisms involved in the incretin response to DGAT1 inhibition,other interventions [inhibitors of dipeptidyl peptidase-IV(sitagliptin),pancreatic lipase(Orlistat),GPR119 knockout mice] were evaluated.RESULTS DGAT1 deficient mice and wildtype C57/BL6J mice werelipid challenged and levels of both active and total GLP-1 in the plasma were increased.This response was further augmented with DGAT1 inhibitor PF-04620110 treated wildtype mice.Furthermore,PF-04620110 was able to dose responsively increase GLP-1 and PYY,but blunt GIP at all doses of PF-04620110 during lipid challenge.Combination treatment of PF-04620110 and Sitagliptin in wildtype mice during a lipid challenge synergistically enhanced postprandial levels of active GLP-1.In contrast,in a combination study with Orlistat,the ability of PF-04620110 to elicit an enhanced incretin response was abrogated.To further explore this observation,GPR119 knockout mice were evaluated.In response to a lipid challenge,GPR119 knockout mice exhibited no increase in active or total GLP-1 and PYY.However,PF-04620110 was able to increase total GLP-1 and PYY in GPR119 knockout mice as compared to vehicle treated wildtype mice.CONCLUSION Collectively,these data provide some insight into the mechanism by which inhibition of DGAT1 enhances intestinal hormone release.

Extracellular vesicles:General features and usefulness in diagnosis and therapeutic management of colorectal cancer

In the world,among all type of cancers,colorectal cancer(CRC)is the third most commonly diagnosed in males and the second in females.In most of cases,(RP1)patients’prognosis limitation with malignant tumors can be attributed to delayed diagnosis of the disease.Identification of patients with early-stage disease leads to more effective therapeutic interventions.Therefore,new screening methods and further innovative treatment approaches are mandatory as they may lead to an increase in progression-free and overall survival rates.For the last decade,the interest in extracellular vesicles(EVs)research has exponentially increased as EVs generation appears to be a universal feature of every cell that is strongly involved in many mechanisms of cell-cell communication either in physiological or pathological situations.EVs can cargo biomolecules,such as lipids,proteins,nucleic acids and generate transmission signal through the intercellular transfer of their content.By this mechanism,tumor cells can recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination.This review intends to cover the most recent literature on the role of EVs production in colorectal normal and cancer tissues.Specific attention is paid to the use of EVs for early CRC diagnosis,follow-up,and prognosis as EVs have come into the spotlight of research as a high potential source of‘liquid biopsies’.The use of EVs as new targets or nanovectors as drug delivery systems for CRC therapy is also summarized.

Synthesis, Crystal Structure, Cytotoxic, Antileishmanial and Docking Evaluation of 3-(4-Chloro-3-nitrophenyl)-1-phenylprop-2-en-1-one

Chalcone derivatives are of immense importance owing to their superior pharmacological profile. Minor changes in their structures create high degree of diversity that results in a broader spectrum of biological activities. The present research paper presents the synthesis of 3-（4-chloro-3-nitrophenyl）-1-phenylprop-2-en-1-one chalcone（I）, single crystal XRD analysis and the evaluation of its possible biological activities like cytotoxic（LD（50） = 5.40 ug/m L）and antileishmanial（LD（50） = 0.81 ug/m L） activities. The results indicate the tested chalcone（I）shows superior inhibition values against leishmanial promastigotes. Further, the possible interaction sites of chalcone（I） with Try R enzyme involved in the redox metabolism of the leishmanial parasite were determined using docking simulation technique. Docking computations demonstrate that the compound establishes prominent binding interactions with the key residues of Try R and possesses the potential to effectively inhibit the catalytic activities of enzyme. Thus the results suggest that the chalcone（I） can serve as a potential scaffold for the treatment of leishmaniasis and deserve further development.

Unraveling the epidemiology of metabolic dysfunction-associated liver cancer:Insights from mixed etiologies,regional variations,and gender disparities

The Korean Republic nationwide cohort study by Yun et al.reveals a stepwise increase in hepatocellular carcinoma(HCC)risk,progressing from“pure”metabolic dysfunction-associated steatotic liver disease(MASLD)to MASLD with increased alcohol intake(MetALD)and then to alcohol-associated liver disease[1].These data also highlight the significant impact of age and gender,underscoring the importance of tailoring prevention strategies to address not only metabolic dysfunction but also alcohol consumption in liver disease management[1].This Korean cohort study also illustrates the characteristics of MASLD-related HCC,providing new insights into the natural history of this liver disease.

Comparative associations of non-alcoholic fatty liver disease and metabolic dysfunction-associated steatotic liver disease with risk of incident chronic kidney disease:a cohort study

Background:We examined the comparative associations between non-alcoholic fatty liver disease(NAFLD)and metabolic dysfunction-associated steatotic liver disease(MASLD)definitions with risk of developing chronic kidney disease(CKD)and abnormal albuminuria.Methods:We conducted a cohort study of 214,145 Korean adults with normal kidney function at baseline who underwent liver ultrasonography.Participants were further subdivided into no steatotic liver disease(no-SLD),NAFLD-only,MASLD-only,both NAFLD and MASLD,and SLD not categorized as NAFLD or MASLD groups.Cox proportional hazards models were used to analyze the risk of incident CKD and albuminuria.Results:Compared with either the no-NAFLD or no-MASLD groups,the NAFLD and MASLD groups were associated with a higher risk of incident CKD(NAFLD:adjusted hazard ratio(HR),1.18[95%CI,1.01-1.38];MASLD:adjusted HR,1.21[95%CI,1.04-1.39]).Among the five subgroups,both NAFLD and MASLD group had the strongest association with risk of incident CKD(adjusted HR,1.21[95%CI,1.04-1.42]).The MASLD-only group had the strongest association with incident abnormal albuminuria,with an adjusted HR comparable to that of the both NAFLD and MASLD group(adjusted HR 1.96[95%CI,1.44-2.67]for the MASLD-only,and adjusted HR 1.98[95%CI,1.58-2.49]for the both NAFLD and MASLD group versus the no-SLD group).The NAFLD-only group was not independently associated with risk of CKD or abnormal albuminuria.Conclusions:These findings suggest that MASLD definition identifies individuals at high risk of developing incident CKD or abnormal albuminuria better than NAFLD definition.

THE POPULATION ASSOCIATION OF GLUCOKINASE GENE WITH TYPE 2 (NONINSULIN-DEPENDENT) DIABETES MELLITUS IN CHINESE

The association of gluckinase (GCK) gene with type 2 (non-insulin-dependent) diabetes mellitus was investigated in 168 Chinese subjects (85 unrelated type 2 diabetics and 83 non-diabetic controls), The microsatellite polymorphism marker, GCK-5', was amplified with polymerase chain reaction. Four alleles were observed in Chinese population with length varying from 137bp to 143bp and the most common one being the 139bp allele 3. In comparison with non-diabetics, allele 4 was significantly increased in type 2 diabetes (10% versus 38, respectively; X(2)=6.773, P=0.009); genotype 44 and 4X (X denotes any allele other than allele 4) were significantly increased in type 2 diabetes (16% versus 6% respectively; X(2)=6.439, P=0.011), The frequency difference was also shown in overweight / obese subgroup comparison (X(2)=7.718, P=0.021), but not in lean / normal-weight subgroup comparison, No differences of age of onset and frequency of positive family history were observed between type 2 diabetic patients with genotype 44 or 4X and those with XX. The risk for type 2 diabetes in Chinese with genotype 44 or 4X was about 3.5 times higher than in Chinese with genotype XX. Therefore, GCK gene was associated with Chinese type 2 diabetes.

The membrane-associated E3 ubiquitin ligase MARCH3 downregulates the IL-6 receptor and suppresses colitis-associated carcinogenesis

The IL-6-STAT3 axis is critically involved in inflammation-associated carcinogenesis(IAC).How this axis is regulated to modulate IAC remains unknown.Here,we show that the plasma membrane-associated E3 ubiquitin ligase MARCH3 negatively regulates STAT3 activation triggered by IL-6,as well as another IL-6 subfamily member,Oncostatin M(OSM).MARCH3 is associated with the IL-6 receptorα-chain(IL-6Rα)and its coreceptor gp130.Biochemical experiments indicated that MARCH3 mediates the polyubiquitination of IL-6Rαat K401 and gp130 at K849 following IL-6 stimulation,leading to their translocation to and degradation in lysosomes.MARCH3 deficiency increases IL-6-and OSM-triggered activation of STAT3 and induction of downstream effector genes in various cell types.MARCH3 deficiency enhances dextran sulfate sodium(DSS)-induced STAT3 activation,increases the expression of inflammatory cytokines,and exacerbates colitis,as well as azoxymethane(AOM)/DSS-induced colitis-associated cancer in mice.In addition,MARCH3 is downregulated in human colorectal cancer tissues and associated with poor survival across different cancer types.Our findings suggest that MARCH3 is a pivotal negative regulator of IL-6-induced STAT3 activation,inflammation,and inflammation-associated carcinogenesis.

Status of adult inpatient burn rehabilitation in Europe: are we neglecting metabolic outcomes?

Background:Hypermetabolism,muscle wasting and insulin resistance are challenging yet important rehabilitation targets in the management of burns.In the absence of concrete practice guidelines,however,it remains unclear how these metabolic targets are currently managed.This study aimed to describe the current practice of inpatient rehabilitation across Europe.Methods:An electronic survey was distributed by the European Burn Association to burn centres throughout Europe,comprising generic and profession-specific questions directed at therapists,medical doctors and dieticians.Questions concerned exercise prescription,metabolic management and treatment priorities,motivation and knowledge of burn-induced metabolic sequelae.Odds ratios were computed to analyse associations between data derived from the responses of treatment priorities and knowledge of burn-induced metabolic sequelae.Results:Fifty-nine clinicians with 12.3±9 years of professional experience in burns,representing 18 out of 91 burn centres(response rate,19.8%)across eight European countries responded.Resistance and aerobic exercises were only provided by 42%and 38%of therapists to intubated patients,87%and 65%once out-of-bed mobility was possible and 97%and 83%once patients were able to leave their hospital room,respectively.The assessment of resting energy expenditure by indirect calorimetry,muscle wasting and insulin resistance was carried out by only 40.7%,15.3%and 7.4%respondents,respectively,with large variability in employed frequency and methods.Not all clinicians changed their care in cases of hypermetabolism(59.3%),muscle wasting(70.4%)or insulin resistance(44.4%),and large variations in management strategies were reported.Significant interdisciplinary variation was present in treatment goal importance ratings,motivation and knowledge of burn-induced metabolic sequelae.The prevention of metabolic sequelae was regarded as the least important treatment goal,while the restoration of functional status was rated as the most important.Knowledge of burn-induced metabolic sequelae was linked to higher importance ratings of metabolic sequelae as a therapy goal(odds ratio,4.63;95%CI,1.50–14.25;p<0.01).Conclusion:This survey reveals considerable non-uniformity around multiple aspects of inpatient rehabilitation across European burn care,including,most notably,a potential neglect of metabolic outcomes.The results contribute to the necessary groundwork to formulate practice guidelines for inpatient burn rehabilitation.

The membrane-associated ubiquitin ligases MARCH2 and MARCH3 target IL-5 receptor alpha to negatively regulate eosinophilic airway inflammation

Interleukin 5(IL-5)plays crucial roles in type 2-high asthma by mediating eosinophil maturation,activation,chemotaxis and survival.Inhibition of IL-5 signaling is considered a strategy for asthma treatment.Here,we identified MARCH2 and MARCH3 as critical negative regulators of IL-5-triggered signaling.MARCH2 and MARCH3 associate with the IL-5 receptorαchain(IL-5Rα)and mediate its K27-linked polyubiquitination at K379 and K383,respectively,and its subsequent lysosomal degradation.Deficiency of MARCH2 or MARCH3 modestly increases the level of IL-5Rαand enhances IL-5-induced signaling,whereas double knockout of MARCH2/3 has a more dramatic effect.March2/3 double knockout markedly increases the proportions of eosinophils in the bone marrow and peripheral blood in mice.Double knockout of March2/3 aggravates ovalbumin(OVA)-induced eosinophilia and causes increased inflammatory cell infiltration,peribronchial mucus secretion and production of Th2 cytokines.Neutralization of Il-5 attenuates OVA-induced airway inflammation and the enhanced effects of March2/3 double deficiency.These findings suggest that MARCH2 and MARCH3 play redundant roles in targeting IL-5Rαfor degradation and negatively regulating allergic airway inflammation.

MARCH3 negatively regulates IL-3-triggered inflammatory response by mediating K48-linked polyubiquitination and degradation of IL-3Rα

Interleukin-3(IL-3)is a hematopoietic growth factor and critical regulator of inflammatory response such as sepsis.IL-3 binds to IL-3 receptorα(IL-3Rα),which is then associated with IL-3Rβto initiate signaling.How IL-3-triggered physiological and pathological effects are regulated at the receptor level is unclear.Here,we show that the plasma membrane-associated E3 ubiquitin ligase MARCH3 negatively regulates IL-3-triggered signaling.MARCH3 is associated with IL-3Rα,mediates its K48-linked polyubiquitination at K377 and promotes its proteasomal degradation.MARCH3-deficiency promotes IL-3-triggered transcription of downstream effector genes and IL-3-induced expansion of myeloid cells.In the cecal ligation and puncture(CLP)model of sepsis,MARCH3-deficiency aggravates IL-3-ampified expression of inflammatory cytokines,organ damage and inflammatory death.Our findings suggest that regulation of IL-3Rαby MARCH3 plays an important role in IL-3-triggered physiological functions and inflammatory diseases.

Development of cystathionine gamma-lyase-specific microRNAs

The gasotransmitter role of H2S in mammalian has been extensively studied, and cystathionine gammalyase （CSE） is the major H2S-producing enzyme in vascular system. Dysregulation of CSE/H2S system was found in various pathophysiological conditions. MicroRNA （miRNA） and short interfering RNA （siRNA） are known to inhibit gene expression by mRNA degradation and/or translation repression. The regulation of CSE expression by miRNA and siRNA has been reported recently, but the off-target effect of miRNA and the lower knockdown efficiency of siRNA have shadowed the application of these approaches. In the present study, we designed CSE-specific miRNAs based on the rules of miRNA-mRNA complementary and human CSE cDNA sequence. The CSE-specific miRNAs significantly inhibited CSE expression and H2S production, increased reactive oxygen species generation, and induced proliferation of human aorta smooth muscle cells （HASMCs）. The designed CSE-specific miRNAs specifically targeted on CSE gene as evidenced by the direct inhibition of luciferase activity from reporter gene containing human CSE 3t-UTR sequence. The expression of other genes, such as estrogen receptor a, heme oxygenase 1, specificity protein 1, and 3-mercaptopyruvate sulfurtransferase, was not affected by the CSE-specific miRNAs.Compared with CSE-siRNAs, CSE-specific miRNAs dis- played significantly higher efficacy in suppressing CSE expression and H2S production, miR-143, a highly expressed miRNA in vascular system, down-regulated the expressions of CSE as well as other genes, such as insulin-like growth factor binding protein 5 and kruppel-like factor 4. miR-143 suppressed H2S production but had no effect on HASMC proliferation. In conclusion, CSE-specific miRNAs designed in our study provide a highly effective research tool for regulating CSE expression and H2S production. These CSE-specific miRNAs have potential as being novel therapeutic agents for treating vascular disorders related to abnormal oxidative stress and SMC growth.

Regulation ofα-cell glucagon secretion:The role of second messengers

Glucagon is a potent glucose-elevating hormone that is secreted by pancreaticα-cells.While well-controlled glucagon secretion plays an important role in maintaining systemic glucose homeostasis and preventing hypoglycaemia,it is increasingly apparent that defects in the regulation of glucagon secretion contribute to impaired counter-regulation and hyperglycaemia in diabetes.It has therefore been proposed that pharmacological interventions targeting glucagon secretion/signalling can have great potential in improving glycaemic control of patients with diabetes.However,despite decades of research,a consensus on the precise mechanisms of glucose regulation of glucagon secretion is yet to be reached.Second messengers are a group of small intracellular molecules that relay extracellular signals to the intracellular signalling cascade,modulating cellular functions.There is a growing body of evidence that second messengers,such as cAMP and Ca^(2+),play critical roles inα-cell glucose-sensing and glucagon secretion.In this review,we discuss the impact of second messengers onα-cell electrical activity,intracellular Ca^(2+)dynamics and cell exocytosis.We highlight the possibility that the interaction between different second messengers may play a key role in the glucose-regulation of glucagon secretion.