The Protective Role of Prolyl Oligopeptidase (POP) Inhibition in Kidney Injury Induced by Renal Ischemia-Reperfusion

Characterization, Semirational Design for pH Robustness, and the Application in Bioactive Peptide Production of a X-Prolyl Dipeptidyl Aminopeptidase from Lactococcus lactis MY-3

PepXLcMY-3, an X-prolyl dipeptidyl aminopeptidase derived from Lactobacillus lactis MY-3, was screened and recombinantly expressed in Escherichia coli. The enzyme could exhibit about 40% activity within the pH range of 6.0-10. To further improve the pH robustness, site E396 located in the active pocket was discovered through alanine scanning. The mutant E396I displayed both developed activity and kcat/Km. The optimal pH of E396I shifted from 6.0 to 10 compared to WT, with the relative activity within the pH range of 6.0-10 significantly increased. The site K648 was then proposed by semirational design. The activity of mutant E396I/K648D reached 4.03 U/mg. The optimal pH was restored to 6.0, and the pH stability was further improved. E396I/K648D could totally hydrolyze β-casomorphin 7 within 30 min. The hydrolysate showed 64.5% inhibition on angiotensin I converting enzyme, which was more efficient than those produced by E396I and WT, 23.2 and 44.7%, respectively.

Prolyl oligopeptidase inhibition ameliorates experimental pulmonary fibrosis both in vivo and in vitro

BACKGROUND

Pulmonary fibrosis is a progressive disease characterized by lung remodeling due to excessive deposition of extracellular matrix. Although the etiology remains unknown, aberrant angiogenesis and inflammation play an important role in the development of this pathology. In this context, recent scientific research has identified new molecules involved in angiogenesis and inflammation, such as the prolyl oligopeptidase (PREP), a proteolytic enzyme belonging to the serine protease family, linked to the pathology of many lung diseases such as pulmonary fibrosis. Therefore, the aim of this study was to investigate the effect of a selective inhibitor of PREP, known as KYP-2047, in an in vitro and in an in vivo model of pulmonary fibrosis.

METHODS

The in vitro model was performed using human alveolar A549 cells. Cells were exposed to lipopolysaccharide (LPS) 10 μg/ml and then, cells were treated with KYP-2047 at the concentrations of 1 μM, 10 μM and 50 μM. Cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide colorimetric assay, while inflammatory protein expression was assessed by western blots analysis. The in vivo model was induced in mice by intra-tracheal administration of bleomycin (1 mg/kg) and then treated intraperitoneally with KYP-2047 at doses of 1, 2.5 and 5 mg/kg once daily for 12 days and then mice were sacrificed, and lung tissues were collected for analyses.

RESULTS

The in vitro results demonstrated that KYP-2047 preserved cell viability, reduced inflammatory process by decreasing IL-18 and TNF-α, and modulated lipid peroxidation as well as nitrosative stress. The in vivo pulmonary fibrosis has demonstrated that KYP-2047 was able to restore histological alterations reducing lung injury. Our data demonstrated that KYP-2047 significantly reduced angiogenesis process and the fibrotic damage modulating the expression of fibrotic markers. Furthermore, KYP-2047 treatment modulated the IκBα/NF-κB pathway and reduced the expression of related pro-inflammatory enzymes and cytokines. Moreover, KYP-2047 was able to modulate the JAK2/STAT3 pathway, highly involved in pulmonary fibrosis.

CONCLUSION

In conclusion, this study demonstrated the involvement of PREP in the pathogenesis of pulmonary fibrosis and that its inhibition by KYP-2047 has a protective role in lung injury induced by BLM, suggesting PREP as a potential target therapy for pulmonary fibrosis. These results speculate the potential protective mechanism of KYP-2047 through the modulation of JAK2/STAT3 and NF-κB pathways.

Inhibition of LRRK2 Attenuates Depression-Related Symptoms in Mice with Moderate Traumatic Brain Injury

Moderate traumatic brain injury (mTBI) has been associated with emotional dysregulation such as loss of consciousness, post-traumatic amnesia and major depressive disorder. The gene Leucine-rich repeat kinase 2 (LRRK2) is involved in protein synthesis and degradation, apoptosis, inflammation and oxidative stress, processes that trigger mTBI. The aim of this study was to investigate the role of LRRK2 in reducing depression-related symptoms after mTBI and to determine whether inhibition of LRRK2 mediated by PF-06447475 could have antidepressant effects. Moderate traumatic brain injury was induced by controlled cortical impact (CCI) and mice were treated with PF-06447475 at doses of 1, 2.5 and 5 mg/kg once daily for 14 days. We performed histological, immunohistochemical and molecular analyses of brain tissue 24 days after mTBI. Furthermore, the tissue changes found in the hippocampus and amygdala confirmed the depression-like behavior. PF-treatment with 06447475 significantly reduced the histological damage and behavioral disturbances. Thus, this study has shown that mTBI induction promotes the development of depression-like behavioral changes. LRRK2 inhibition showed an antidepressant effect and restored the changes in the copper/glutamate/N-methyl-D-aspartic acid receptor (Cu/NMDAR) system.

Molecular Pathology, Diagnostics, and Therapeutics of Nephropathy

Years of standing still have ended, and the field of nephrology has seen a plethora of clinical trials, changing the therapeutic landscape of chronic kidney disease (CKD) and immune-mediated kidney disease management [...].

Efficacy comparison of restrictive versus massive fluid resuscitation in patients with traumatic hemorrhagic shock

OBJECTIVE

To compare the therapeutic effect and safety of restrictive versus massive fluid resuscitation in patients with traumatic hemorrhagic shock (TSH).

METHODS

Ninety TSH patients treated in the ICU of the Second Affiliated Hospital of Zhejiang University School of Medicine from June 2020 to January 2021 were recruited for this retrospective study. Among them, 47 cases received restrictive fluid resuscitation (RFR) after admission who were considered as the observation group (OG), while the other 43 cases were given massive fluid resuscitation (MFR) who were treated as the control group (CG). The clinical indices, coagulation function, blood gas analysis, mortality within 72 h, duration of mechanical ventilation, and ICU stay were compared between the two groups, and the amount of resuscitation fluid given and complications that occurred during treatment were recorded. Multivariate logistic regression analysis was used to screen the independent risk factors for complications.

RESULTS

In comparison to the CG, the resuscitation time, infusion volume, and lactate level in the OG were lower after treatment, while the hemoglobin level and blood gas residual base value (BE) were higher. Besides, the activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) levels and arterial blood carbon dioxide partial pressure (PaCO₂) in the OG were lower, while arterial blood oxygen partial pressure (PaO₂) and pH were higher. The duration of mechanical ventilation and ICU stay in the OG after treatment were lower, and there was no statistical difference in mortality and complication rates within 72 h. Lower mean arterial pressure (MAP), higher APACHE II (Acute Physiology and Chronic Health Evaluation II) and longer resuscitation time were independent risk factors for complications in patients with traumatic shock.

CONCLUSION

TSH treatment with RFR can effectively accelerate patients' resuscitation with less volume of infusion of resuscitation fluid, reduced time of mechanical ventilation and ICU hospitalization, and promote the recovery of coagulation function. It has good effects and is very suitable for clinical application.

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.