Physiology, pharmacology and prospects for dipeptidilpeptidase-4 inhibitors use

Modern requirements for the treatment of type 2 diabetes mellitus (DM2) include not only achieving a glycemic control, but also reducing the risk of developing cardiovascular complications. Dipeptidyl peptidase 4 (DPP-4) inhibitors are inferior in the effectiveness to some other actively developing groups of hypoglycemic drugs (SGLT2 inhibitors and GLP-1 receptor agonists);however, they seem relevant at the present time.The aim of the study is to analyze the literature data on the therapeutic potential and results of the of DPP-4 inhibitors research.Materials and methods. When searching for the review article materials, the ing databases of PubMed, Google Scholar and e-Library were used. The search was carried out on the publications for the period from 2006 to 2022, using the following keywords: DPP-4 inhibitors;glucagonlike peptide-1 (GLP-1);glucose-dependent insulinotropic peptide (GIP);sitagliptin, and other drugs.Results. DPP-4 belongs to the serine proteases family and is involved in the degradation of various chemokines and peptide hormones, including incretins secreted by intestinal L-and K-cells - GLP-1 and GIP. They regulate a postprandial insulin secretion and a beta-cell function, modulate a fasting and postprandial glucagon secretion, regulate the eating behavior and have many pleiotropic (immunomodulatory, anti-inflammatory, antifibrotic, etc.) effects. DPP-4 inhibitors reduce an enzyme activity by 70-90%, increasing plasma incretin levels by 2-4 times and have been used to treat DM2 since 2006. Now there are 13 DPP-4 inhibitors on the market in different countries, differing primarily in pharmacokinetic parameters. They are actively used in the combination therapy for type 2 diabetes, increasing the glycemic control effectiveness without increasing the risk of hypoglycemia. The evidence is emerging about the therapeutic potential of DPP-4 inhibitors in COVID-19.Conclusion. A peroral form, an ability to create effective combinations with other hypoglycemic drugs without increasing the risk of hypoglycemia, the pleiotropic effects of DPP-4 inhibitors, make this group relevant at the present time.

Screening compounds for treating the diabetes and COVID-19 from Miao medicine by molecular docking and bioinformatics.

Both diabetes and Corona Virus Disease 2019 (COVID-19) are seriously harmful to human health, and they are closely related. It is of great significance to find drugs that can simultaneously treat diabetes and COVID-19. Based on the theory of traditional Chinese medicine for treating COVID-19, this study first sorted out the compounds of Guizhou Miao medicine with "return to the lung channel" and "clear heat and detoxify" effects in China. The active components against COVID-19 were screened by molecular docking with SARS-CoV-2 PLpro and angiotensin-converting enzyme II as targets. Furthermore, the common target dipeptidyl peptidase 4 (DPP4) of diabetes and COVID-19 was used as a screening protein, and molecular docking was used to obtain potential components for the treatment of diabetes and COVID-19. Finally, the mechanism of potential ingredients in the treatment of diabetes and COVID-19 was explored with bioinformatics. More than 80 kinds of Miao medicine were obtained, and 584 compounds were obtained. Further, 110 compounds against COVID-19 were screened, and top 6 potential ingredients for the treatment of diabetes and COVID-19 were screened, including 3-O-ß-D-Xylopyranosyl-(1-6)-ß-D-glucopyranosyl-(1-6)-ß-D-glucopyranosyl oleanolic acid 28-O-ß-D-glucopyranosyl ester, Glycyrrhizic acid, Sequoiaflavone, 2-O-Caffeoyl maslinic acid, Pholidotin, and Ambewelamide A. Bioinformatics analysis found that their mechanism of action in treating diabetes and COVID-19 may be related to regulating the expression of DPP4, angiotensin II type 1 receptor, vitamin D receptor, plasminogen, chemokine C-C-motif receptor 6, and interleukin 2. We believe that Guizhou Miao medicine is rich in potential ingredients for the treatment of diabetes and COVID-19.

Hypoglycemic Therapy and the Course of Post-Covid Syndrome, is There a Connection?

Diabetes mellitus (both type 1 and type 2) is considered one of the risk factors for severe COVID-19 and death from this infection. Past infection with COVID-19 leads to deterioration in the control of existing diabetes mellitus, progression of pre-diabetes to diabetes, an increase in the number of new cases of diabetes and an increase in the proportion of glucocorticoid-induced diabetes, which significantly aggravates the course of post-COVID syndrome for this category of patients. Antihyperglycemic drugs may influence the pathogenesis of COVID-19, which may be of relevance for the treatment of patients with type 2 diabetes mellitus and post-COVID syndrome. The review also presents our own data on the effect of various regimens of oral hypoglycemic agents on post-COVID syndrome in people with type 2 diabetes mellitus. The observation showed that the use of dipeptidyl peptidase-4 inhibitors as part of a treatment strategy in patients with type 2 diabetes mellitus with a past COVID-19 infection was associated with a decrease in the duration and severity of post-COVID symptoms.Copyright © 2023 The Russian Archives of Internal Medicine. All rights reserved.

Accurate Assessment and Tracking the Process of Liver-Specific Injury by the Residual Tissue Activity of Carboxylesterase 1 and Dipeptidyl Peptidase 4

Accurately assessing and tracking the progression of liver-specific injury remains a major challenge in the field of biomarker research. Here, we took a retrospective validation approach built on the mutuality between serum and tissue biomarkers to characterize the liver-specific damage of bile duct cells caused by a-naphthyl isothiocyanate (ANIT). We found that carboxylesterase 1 (CES1), as an intrahepatic marker, and dipeptidyl peptidase 4 (DPP-IV), as an extrahepatic marker, can reflect the different pathophysiolo-gies of liver injury. Levels of CES1 and DPP-IV can be used to identify liver damage itself and the inflam-matory state, respectively. While the levels of the conventional serological biomarkers alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were all con-comitantly elevated in serum and tissues after ANIT-induced injury, the levels of bile acids decreased in bile, increased in serum, and ascended in intrahepatic tissue. Although the level of c-glutamyl transpeptidase (c-GT) changed in an opposite direction, the duration was much shorter than that of CES1 and was quickly restored to normal levels. Therefore, among the abovementioned biomarkers, only CES1 made it possible to specifically determine whether the liver cells were destroyed or damaged with-out interference from inflammation. CES1 also enabled accurate assessment of the anti-cholestasis effects of ursodeoxycholic acid (UDCA;single component) and Qing Fei Pai Du Decoction (QFPDD;multi-component). We found that both QFPDD and UDCA attenuated ANIT-induced liver damage. UDCA was more potent in promoting bile excretion but showed relatively weaker anti-injury and anti-inflammatory effects than QFPDD, whereas QFPDD was more effective in blocking liver inflammation and repairing liver damage. Our data highlights the potential of the combined use of CES1 (as an intra-hepatic marker of liver damage) and DPP-IV (as an extrahepatic marker of inflammation) for the accurate evaluation and tracking of liver-specific injury-an application that allows for the differentiation of liver damage and inflammatory liver injury.(c) 2021 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

DPP-4 Inhibitors as a savior for COVID-19 patients with diabetes.

Diabetic patients are at particular risk of severe COVID-19. Human dipeptidyl peptidase-4 (DPP-4) is a membrane-bound aminopeptidase that regulates insulin release by inactivating incretin. DPP-4 inhibitors (DPP-4is) are therefore used as oral anti-diabetic drugs to restore normal insulin levels. These molecules also have anti-inflammatory and anti-hypertension effects. Recent studies on the interactions of SARS-CoV-2 spike glycoprotein and DPP-4 predict a possible entry route for SARS-CoV-2. Therefore, DPP-4is could be effective at reducing the virus-induced 'cytokine storm', thereby ceasing inflammatory injury to vital organs. Moreover, DPP-4is may interfere with viral entry into host cells. Herein, we have reviewed the efficacy of DPP-4is as potential repurposed drugs to reduce the severity of SARS-CoV-2 infection in patients with diabetes.

Association between use of novel glucose-lowering drugs and COVID-19 hospitalization and death in patients with type 2 diabetes: a nationwide registry analysis.

AIMS: Type 2 diabetes (T2DM) in patients with coronavirus disease-19 (COVID-19) is associated with worse prognosis. We separately investigated the associations between the use of sodium-glucose cotransporter 2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP-1 RA) and dipeptidyl peptidase-4 inhibitors (DPP-4i), and the risk of COVID-19 hospitalization and death. METHODS AND RESULTS: Patients with T2DM registered in the Swedish National Patient Registry and alive on 1st February 2020 were included. "Incident severe COVID-19" was defined as the first hospitalization and/or death from COVID-19. A modified Poisson regression approach was applied to a 1:1 propensity score-matched population receiving vs. not receiving SGLT2i, GLP-1 RA and DPP-4i to analyze the associations between their use and I) incident severe COVID-19, II) risk of 30-day mortality in patients hospitalized for COVID-19.Among 344,413 patients, 39,172 (11%) were treated with SGLT2i, 34,290 (10%) with GLP-1 RA and 53,044 (15%) with DPP-4i; 9,538 (2.8%) had incident severe COVID-19 by 15th May 2021. SGLT2i and DPP-4i were associated with a 10% and 11% higher risk of incident severe COVID-19, respectively, whereas there was no association for GLP-1 RA. DPP-4i were also associated with a 10% higher 30-day mortality in patients hospitalized for COVID-19, whereas there was no association for SGLT2i and GLP-1 RA. CONCLUSION: SGLT2i and DPP-4i use was associated with higher risk of incident severe COVID-19. DPP-4i use was associated with higher 30-day mortality in patients with COVID-19, whereas SGLT2i use was not. No increased risk for any outcome was observed with GLP-1 RA.

Molecular Docking Studies of Coronavirinae Spike Proteins with Different Vertebrate Receptors (ACE2, APN, DPP4)

Coronaviruses (CoVs) display prevalence and great cross-transmissibility due to diverse receptor recognition and high mutability of their spike proteins. In this study, spike protein interactions that influence coronavirus evolution and complex virology were determined. To establish coronavirus classification, phylogenetic analysis of spike proteins based on maximum likelihood was performed using MEGA X. To identify the most suitable interactions between spike proteins and vertebrate cell receptors, molecular docking between full spike proteins and angiotensin-converting enzyme 2 (ACE2), aminopeptidase N (APN), and dipeptidyl peptidase 4 (DPP4) receptors from vertebrates was performed using Hex, a 6D spherical polar Fourier (SPF) transform-based software. Results supported the current coronavirus taxonomy, and molecular docking showed that highly different classes recognized similar receptors. Specifically, spike protein of Munia CoV with cat ACE2 (E = -478.3 kcal/mol) and for SARS-CoV-2 variants, spike protein of alpha with chicken ACE2 (E = -349.6 kcal/mol) formed the most suitable interactions. SARS-CoV-2 variants showed additional affinity toward chicken and cat receptors. Therefore, preferred cell receptor and animal hosts were predicted for all coronaviruses using a sequence-based approach which may serve as future guide for further studies. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Dipeptidyl Peptidase-4 Inhibitors, Glucagon-like Peptide-1 Receptor Agonists, and Sodium-Glucose Cotransporter-2 Inhibitors and COVID-19 Outcomes.

PURPOSE: It has been reported that dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP-1 RA), and sodium-glucose cotransporter-2 inhibitors (SGLT-2i) have a role in modulation of inflammation associated with coronavirus disease 2019 (COVID-19). This study assessed the effect of these drug classes on COVID-19-related outcomes. METHODS: Using a COVID-19 linkable administrative database, we selected patients aged ≥40 years with at least 2 prescriptions of DPP-4i, GLP-1 RA, or SGLT-2i or any other antihyperglycemic drug and a diagnosis of COVID-19 from February 15, 2020, to March 15, 2021. Adjusted odds ratios (ORs) with 95% CIs were used to calculate the association between treatments and all-cause and in-hospital mortality and COVID-19-related hospitalization. A sensitivity analysis was performed by using inverse probability treatment weighting. FINDINGS: Overall, 32,853 subjects were included in the analysis. Multivariable models showed a reduction of the risk for COVID-19 outcomes for users of DPP-4i, GLP-1 RA, and SGLT-2i compared with nonusers, although statistical significance was reached only in DPP-4i users for total mortality (OR, 0.89; 95% CI, 0.82-0.97). The sensitivity analysis confirmed the main results reaching a significant reduction for hospital admission in GLP-1 RA users and in-hospital mortality in SGLT-2i users compared with nonusers. IMPLICATIONS: This study found a beneficial effect in the risk reduction of COVID-19 total mortality in DPP-4i users compared with nonusers. A positive trend was also observed in users of GLP-1 RA and SGLT-2i compared with nonusers. Randomized clinical trials are needed to confirm the effect of these drug classes as potential therapy for the treatment of COVID-19.

A bat MERS-like coronavirus circulates in pangolins and utilizes human DPP4 and host proteases for cell entry.

It is unknown whether pangolins, the most trafficked mammals, play a role in the zoonotic transmission of bat coronaviruses. We report the circulation of a novel MERS-like coronavirus in Malayan pangolins, named Manis javanica HKU4-related coronavirus (MjHKU4r-CoV). Among 86 animals, four tested positive by pan-CoV PCR, and seven tested seropositive (11 and 12.8%). Four nearly identical (99.9%) genome sequences were obtained, and one virus was isolated (MjHKU4r-CoV-1). This virus utilizes human dipeptidyl peptidase-4 (hDPP4) as a receptor and host proteases for cell infection, which is enhanced by a furin cleavage site that is absent in all known bat HKU4r-CoVs. The MjHKU4r-CoV-1 spike shows higher binding affinity for hDPP4, and MjHKU4r-CoV-1 has a wider host range than bat HKU4-CoV. MjHKU4r-CoV-1 is infectious and pathogenic in human airways and intestinal organs and in hDPP4-transgenic mice. Our study highlights the importance of pangolins as reservoir hosts of coronaviruses poised for human disease emergence.

SARS-CoV-2 vaccine-triggered conversion from systemic lupus erythematosus (SLE) to bullous SLE and dipeptidyl peptidase 4 inhibitors-associated bullous pemphigoid.

Bullous systemic lupus erythematosus (BSLE) is a rare blistering disease in patients with SLE. BSLE is a heterogenous disease caused by autoantibodies to the basement membrane, mainly type VII collagen. The pathogenesis of the development of autoantibodies in BSLE remains unknown. We report a case of SLE taking dipeptidyl peptidase 4 inhibitors (DPP4i) who developed tense blister lesions after administration of SARS-CoV-2 vaccine. Initial erythematous lesion before administration of SARS-CoV-2 vaccine had not shown IgG deposition at basement membrane both direct and indirect immunofluorescence (IIF). However, the result of those examinations became positive after the administration of SARS-CoV-2 vaccine. Furthermore, IIF test results using NaCl split skin had shown positive against epidermal side. These observations suggest that SARS-CoV-2 vaccination triggered production of autoantibodies that cause bullous SLE. The present case fulfills the diagnostic criteria for both BSLE and DPP4i-associated bullous pemphigoid. Skin lesions were cleared after withdrawal of DPP4i. Therefore, physicians should ask patients who develop blisters after the vaccination whether they are taking DPP4i.

Dipeptidyl peptidase 4 inhibitors in COVID-19: Beyond glycemic control.

Coronavirus disease 2019 (COVID-19) is associated with a high risk of mortality and complications in patients with diabetes mellitus. Achieving good glycemic control is very important in diabetic patients to reduce complications and mortality due to COVID-19. Recent studies have shown the mortality benefit and anti-inflammatory effects of Dipeptidyl-peptidase-4 inhibitors (DPP-4i) in diabetic patients with COVID-19. DPP-4i may have a beneficial role in halting the severity of infection primarily by three routes, namely viral entry inhibition, anti-inflammatory and anti-fibrotic effects and glycemic control. This has raised the pro-mising hypothesis that DPP-4i might be an optimal strategy for treating COVID-19 in patients with diabetes. This review aims to summarise the possible therapeutic non-glycemic effects of DPP-4i in diabetic patients diagnosed with COVID-19 in the light of available evidence.

In vitro evaluation of 2-pyrazoline derivatives as DPP-4 inhibitors

Objectives In this study, the synthesis of three pyrazoline derivatives and the evaluation of their inhibitory effects on dipeptidyl peptidase (DPP-4) were aimed. Materials and methods Pyrazoline-based compounds (1-3) were obtained via the reaction of 1-(2-furyl)-3-(1,3-benzodioxol-5-yl)-2-propen-1-one with 4-substituted phenylhydrazine hydrochloride. The DPP-4 inhibitory effects of compounds 1-3 were determined with a fluorometric assay using Gly-Pro-Aminomethylcoumarin as the fluorogenic substrate. The cytotoxicity of compounds 1-3 on L929 mouse fibroblast (healthy) cell line was evaluated using MTT assay. Results 1-(4-Methylsulfonylphenyl)-3-(2-furyl)-5-(1,3-benzodioxol-5-yl)-2-pyrazoline (2) exhibited the highest DPP-4 inhibitory activity (IC50=5.75 +/- 0.35 mu M). Moreover, compound 2 exerted no significant cytotoxicity against L929 cells (IC50=34.33 +/- 7.09 mu M). Conclusions Target compounds exhibited moderate DPP-4 inhibitory activity and compound 2 was identified as the most active compound.

Non-Insulin Novel Antidiabetic Drugs Mechanisms in the Pathogenesis of COVID-19.

The present study aimed to analyse the published data and to realize an update about the use and pathogenesis of the novel antidiabetic drugs, respectively, dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP-1 Ra), and sodium-glucose co-transporter-2 inhibitors (SGLT-2i), in patients with type 2 diabetes mellitus (T2DM) and coronavirus disease (COVID-19). Literature research in the PubMed and Web of Science database was performed in order to identify relevant published clinical trials and meta-analyses that include information about the treatment with novel antidiabetic agents in patients with T2DM and COVID-19. A total of seven articles were included, and their primary and secondary outcomes were reported and analysed. DPP-4i has mixed results on mortality in T2DM patients with COVID-19 but with an overall slightly favourable or neutral effect, whereas GLP-1 Ra seems to have a rather beneficial impact, while SGLT-2i may be useful in acute illness. Even if there are limited data, they seem to have favourable efficacy and safety profiles. The available evidence is heterogenous and insufficient to evaluate if the benefits of non-insulin novel antidiabetic drugs in COVID-19 treatment are due to the improvement of glycaemic control or to their intrinsic anti-inflammatory effects but highlights their beneficial effects in the pathogenesis and evolution of the disease.

Is sitagliptin effective for SARS-CoV-2 infection: false or true prophecy?

Coronavirus disease 2019 (Covid-19) is caused by severe acute respiratory syndrome type 2 (SARS-CoV-2). Covid-19 is characterized by hyperinflammation, oxidative stress, and multi-organ injury (MOI) such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Covid-19 is mainly presented with respiratory manifestations; however, extra-pulmonary manifestations may also occur. Extra-pulmonary manifestations of Covid-19 are numerous including: neurological, cardiovascular, renal, endocrine, and hematological complications. Notably, a cluster of differentiation 26 (CD26) or dipeptidyl peptidase-4 (DPP-4) emerged as a new receptor for entry of SARS-CoV-2. Therefore, DPP-4 inhibitors like sitagliptin could be effective in treating Covid-19. Hence, we aimed in the present critical review to assess the potential role of sitagliptin in Covid-19. DPP-4 inhibitors are effective against the increased severity of SARS-CoV-2 infections. Moreover, DPP-4 inhibitors inhibit the interaction between DPP-4 and scaffolding proteins which are essential for endosome formation and replication of SARS-CoV-2. Therefore, sitagliptin through attenuation of the inflammatory signaling pathway and augmentation of stromal-derived factor-1 (SDF-1) may decrease the pathogenesis of SARS-CoV-2 infection and could be a possible therapeutic modality in treating Covid-19 patients. In conclusion, the DPP-4 receptor is regarded as a potential receptor for the binding and entry of SARS-CoV-2. Inhibition of these receptors by the DPP-4 inhibitor, sitagliptin, can reduce the pathogenesis of the infection caused by SARS-CoV-2 and their associated activation of the inflammatory signaling pathways.

Single domain antibodies derived from ancient animals as broadly neutralizing agents for SARS-CoV-2 and other coronaviruses.

With severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as an emergent human virus since December 2019, the world population is susceptible to coronavirus disease 2019 (COVID-19). SARS-CoV-2 has higher transmissibility than the previous coronaviruses, associated by the ribonucleic acid (RNA) virus nature with high mutation rate, caused SARS-CoV-2 variants to arise while circulating worldwide. Neutralizing antibodies are identified as immediate and direct-acting therapeutic against COVID-19. Single-domain antibodies (sdAbs), as small biomolecules with non-complex structure and intrinsic stability, can acquire antigen-binding capabilities comparable to conventional antibodies, which serve as an attractive neutralizing solution. SARS-CoV-2 spike protein attaches to human angiotensin-converting enzyme 2 (ACE2) receptor on lung epithelial cells to initiate viral infection, serves as potential therapeutic target. sdAbs have shown broad neutralization towards SARS-CoV-2 with various mutations, effectively stop and prevent infection while efficiently block mutational escape. In addition, sdAbs can be developed into multivalent antibodies or inhaled biotherapeutics against COVID-19.

Does DPP-4 inhibitor treatment affect the clinical outcomes of COVID-19 in type 2 diabetes mellitus patients?

OBJECTIVE: We aim to investigate whether the use of dipeptidyl peptidase inhibitors (DPP-4i) affects the severity of disease, hospital mortality, and 3-month post-discharge mortality in type 2 diabetes mellitus (T2DM) individuals with coronavirus disease 2019 (COVID-19) infection. METHODS: The study included 217 patients with type 2 diabetes hospitalized due to COVID-19 between March and October 2020. The patients included in the study were divided into two groups those using DPP-4i and those not using DPP-4i. Demographic characteristics, laboratory parameters, accompanying risk factors, concomitant comorbidities, hospital mortality, clinical course, and 3-month post-discharge mortality were compared between the patients who used DPP-4i and those who did not use. RESULTS: The duration of hospitalization was 10.96±9.16 days in the group using DPP-4i, 12.22±9.1 days in the group not using DPP-4i, and when both groups were evaluated together, it was determined as 11.91±9.11 days. The hospitalization periods were similar between DPP-4i users and non-DPP-4i users (p=0.384). The need for mechanical ventilation (p=0.478 OR 0.710 95% confidence interval [CI], 0.274-1.836) and high-flow nasal cannula (p=0.457, OR: 0.331, 95% CI: 0.41-2.67) were similar between DPP-4i users and non-users. It was determined that the mortality (p=0.208, OR: 0.409, 95% CI: 0.117-1.429) and 3-month post-discharge mortality (p=0.383) were similar in the group using DPP-4i and those not using DPP-4i. CONCLUSION: This study demonstrated that the use of DPP-4i by patients with T2DM in catching COVID-19 does not affect the mortality due to COVID-19, the severity of COVID-19 disease, and 3-month post-discharge mortality.

Screening of potential inhibitors of COVID-19 with repurposing approach via molecular docking.

SARS-CoV-2 (COVID-19) is the causative organism for a pandemic disease with a high rate of infectivity and mortality. In this study, we aimed to assess the affinity between several available small molecule and proteins, including Abl kinase inhibitors, Janus kinase inhibitor, dipeptidyl peptidase 4 inhibitors, RNA-dependent RNA polymerase inhibitors, and Papain-like protease inhibitors, using binding simulation, to test whether they may be effective in inhibiting COVID-19 infection through several mechanisms. The efficiency of inhibitors was evaluated based on docking scores using AutoDock Vina software. Strong ligand-protein interactions were predicted among some of these drugs, that included: Imatinib, Remdesivir, and Telaprevir, and this may render these compounds promising candidates. Some candidate drugs might be efficient in disease control as potential inhibitors or lead compounds against the SARS-CoV-2. It is also worth highlighting the powerful immunomodulatory role of other drugs, such as Abivertinib that inhibits pro-inflammatory cytokine production associated with cytokine release syndrome (CRS) and the progression of COVID-19 infection. The potential role of other Abl kinase inhibitors, including Imatinib in reducing SARS-CoV and MERS-CoV viral titers, immune regulatory function and the development of acute respiratory distress syndrome (ARDS), indicate that this drug may be useful for COVID-19, as the SARS-CoV-2 genome is similar to SARS-CoV.

Proline-specific peptidase activities (DPP4, PRCP, FAP and PREP) in plasma of hospitalized COVID-19 patients.

BACKGROUND: COVID-19 patients experience several features of dysregulated immune system observed in sepsis. We previously showed a dysregulation of several proline-selective peptidases such as dipeptidyl peptidase 4 (DPP4), fibroblast activation protein alpha (FAP), prolyl oligopeptidase (PREP) and prolylcarboxypeptidase (PRCP) in sepsis. In this study, we investigated whether these peptidases are similarly dysregulated in hospitalized COVID-19 patients. METHODS: Fifty-six hospitalized COVID-19 patients and 32 healthy controls were included. Enzymatic activities of DPP4, FAP, PREP and PRCP were measured in samples collected shortly after hospital admission and in longitudinal follow-up samples. RESULTS: Compared to healthy controls, both DPP4 and FAP activities were significantly lower in COVID-19 patients at hospital admission and FAP activity further decreased significantly in the first week of hospitalization. While PRCP activity remained unchanged, PREP activity was significantly increased in COVID-19 patients at hospitalization and further increased during hospital stay and stayed elevated until the day of discharge. CONCLUSION: The changes in activities of proline-selective peptidases in plasma are very similar in COVID-19 and septic shock patients. The pronounced decrease in FAP activity deserves further investigation, both from a pathophysiological viewpoint and as its utility as a part of a biomarker panel.

The Roles of Dipeptidyl Peptidase 4 (DPP4) and DPP4 Inhibitors in Different Lung Diseases: New Evidence.

CD26/Dipeptidyl peptidase 4 (DPP4) is a type II transmembrane glycoprotein that is widely expressed in various organs and cells. It can also exist in body fluids in a soluble form. DPP4 participates in various physiological and pathological processes by regulating energy metabolism, inflammation, and immune function. DPP4 inhibitors have been approved by the Food and Drug Administration (FDA) for the treatment of type 2 diabetes mellitus. More evidence has shown the role of DPP4 in the pathogenesis of lung diseases, since it is highly expressed in the lung parenchyma and the surface of the epithelium, vascular endothelium, and fibroblasts of human bronchi. It is a potential biomarker and therapeutic target for various lung diseases. During the coronavirus disease-19 (COVID-19) global pandemic, DPP4 was found to be an important marker that may play a significant role in disease progression. Some clinical trials on DPP4 inhibitors in COVID-19 are ongoing. DPP4 also affects other infectious respiratory diseases such as Middle East respiratory syndrome and non-infectious lung diseases such as pulmonary fibrosis, lung cancer, chronic obstructive pulmonary disease (COPD), and asthma. This review aims to summarize the roles of DPP4 and its inhibitors in infectious lung diseases and non-infectious diseases to provide new insights for clinical physicians.

Identification of Compounds from Curcuma longa with In Silico Binding Potential against SARS-CoV-2 and Human Host Proteins Involve in Virus Entry and Pathogenesis

Severe acute respiratory syndrome coronavirus 2 and associated coronavirus disease 2019 is a newly identified human coronavirus has imposed a serious threat to global health. The rapid transmission of severe acute respiratory syndrome coronavirus 2 and its ability to spread in humans have prompted the development of new approaches for its treatment. Severe acute respiratory syndrome coronavirus 2 requires RNA-dependent RNA polymerases for life cycle propagation and Spike (S)-protein for attachment to the host cell surface receptors. The virus enters the human body with the assistance of a key functional host receptor dipeptidyl peptidase-4 primed by transmembrane serine protease 2 which are putative targets for drug development. We performed screening of 267 compounds from Curcuma longa L. (Zingiberaceae family) against the viral S-protein and RNA-dependent RNA polymerases and host receptor proteins dipeptidyl peptidase-4 and transmembrane serine protease 2 using in silico molecular docking. Compounds C1, ((4Z,6E)-1,5-dihydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-4,6-dien3-one) and C6 ((4Z,6E)-1,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)hepta-4,6-dien-3-one) exhibited tight binding to the S1 domain of the Spike protein than VE607 and with RNA-dependent RNA polymerase protein more effectively than ribavirin and remdesivir. These compounds also interacted with the human host proteins dipeptidyl peptidase-4 and transmembrane serine protease 2 with higher efficiency than standard inhibitors sitagliptin and camostat mesylate. The lead compounds showed favorable free binding energy for all the studied protein-ligand complexes in Molecular mechanics/Generalized born model and solvent accessibility analysis. Besides, other Curcuma longa compounds C14 and C23 exhibited almost similar potential against these target proteins. The structure based optimization and molecular docking studies have provided information on some lead Curcuma longa compounds with probability for advancement in preclinical research.