Chronic treatment with the (iso-)glutaminyl cyclase inhibitor PQ529 is a novel and effective approach for glomerulonephritis in chronic kidney disease

Therapeutic potential of glutaminyl cyclases: Current status and emerging trends

Glutaminyl cyclase (QC) activity has been identified as a key effector in distinct biological processes. Human glutaminyl-peptide cyclotransferase (QPCT) and glutaminyl-peptide cyclotransferase-like (QPCTL) are considered attractive therapeutic targets in many human disorders, such as neurodegenerative diseases, and a range of inflammatory conditions, as well as for cancer immunotherapy, because of their capacity to modulate cancer immune checkpoint proteins. In this review, we explore the biological functions and structures of QPCT/L enzymes and highlight their therapeutic relevance. We also summarize recent developments in the discovery of small-molecule inhibitors targeting these enzymes, including an overview of preclinical and clinical studies.

Mechanisms of Rostellularia procumbens (L.) Nees on treating chronic glomerulonephritis explored by network pharmacology, RNA-seq, and in vitro experiments

BACKGROUND

The purpose of this study was to demonstrate the in vitro anti-nephritis activity of Rostellularia procumbens (L.) Nees (R. procumbens) extract and to make a preliminary investigation of its anti-nephritis mechanism.

METHODS

A prediction network was built that describes the relationship between R. procumbens and CGN. Then, the potential targets for R. procumbens against CGN were imported into the DAVID database for Gene Ontology (GO) biological annotation analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. A lipopolysaccharide (LPS)-stimulated rat mesangial cell HBZY-1 model in vitro was used to examine the anti-inflammatory activity of R. procumbens extract. RNA-seq was utilized to investigate differentially expressed genes (DEGs) and enriched signaling pathways between groups. Finally, qPCR was used for the validation analysis of the experimental results.

RESULTS

The results of network pharmacology showed that R. procumbens exerts its therapeutic effect on CGN through the AGE-RAGE signaling pathway in diabetic complications, PI3K-Akt, IL-17 signaling pathway, and so on. R. procumbens n-butanol extract (J-NE) can effectively relieve inflammation in HBZY-1. The results of KEGG pathway enrichment suggest that J-NE attenuated CGN was associated with the IL-17 signaling pathway, and the results of RNA-seq were consistent with network pharmacology. Targets enriched in the IL-17 signaling pathway, including Chemokine (C-C motif) ligand 7 (CCL7), Lipocalin 2 (LCN2), Chemokine (C-C motif) ligand 2 (CCL2), and Chemokine (C-X-C motif) ligand 1 (CXCL1), have been identified as crucial targets attenuating CGN by J-NE.

CONCLUSION

R. procumbens is a promising pharmacological candidate for the treatment of CGN in the present era.

Relationship between Macrophages and Tissue Microenvironments in Diabetic Kidneys

Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease. Increasing evidence has suggested that inflammation is a key microenvironment involved in the development and progression of DN. Studies have confirmed that macrophage accumulation is closely related to the progression to human DN. Macrophage phenotype is highly regulated by the surrounding microenvironment in the diabetic kidneys. M1 and M2 macrophages represent distinct and sometimes coexisting functional phenotypes of the same population, with their roles implicated in pathological changes, such as in inflammation and fibrosis associated with the stage of DN. Recent findings from single-cell RNA sequencing of macrophages in DN further confirmed the heterogeneity and plasticity of the macrophages. In addition, intrinsic renal cells interact with macrophages directly or through changes in the tissue microenvironment. Macrophage depletion, modification of its polarization, and autophagy could be potential new therapies for DN.

Anti-Tumor Strategies by Harnessing the Phagocytosis of Macrophages

Macrophages are essential for the human body in both physiological and pathological conditions, engulfing undesirable substances and participating in several processes, such as organism growth, immune regulation, and maintenance of homeostasis. Macrophages play an important role in anti-bacterial and anti-tumoral responses. Aberrance in the phagocytosis of macrophages may lead to the development of several diseases, including tumors. Tumor cells can evade the phagocytosis of macrophages, and "educate" macrophages to become pro-tumoral, resulting in the reduced phagocytosis of macrophages. Hence, harnessing the phagocytosis of macrophages is an important approach to bolster the efficacy of anti-tumor treatment. In this review, we elucidated the underlying phagocytosis mechanisms, such as the equilibrium among phagocytic signals, receptors and their respective signaling pathways, macrophage activation, as well as mitochondrial fission. We also reviewed the recent progress in the area of application strategies on the basis of the phagocytosis mechanism, including strategies targeting the phagocytic signals, antibody-dependent cellular phagocytosis (ADCP), and macrophage activators. We also covered recent studies of Chimeric Antigen Receptor Macrophage (CAR-M)-based anti-tumor therapy. Furthermore, we summarized the shortcomings and future applications of each strategy and look into their prospects with the hope of providing future research directions for developing the application of macrophage phagocytosis-promoting therapy.

Deciphering the role of QPCTL in glioma progression and cancer immunotherapy

Background

Glioma is the most lethal and most aggressive brain cancer, and currently there is no effective treatment. Cancer immunotherapy is an advanced therapy by manipulating immune cells to attack cancer cells and it has been studied a lot in glioma treatment. Targeting the immune checkpoint CD47 or blocking the CD47-SIRPα axis can effectively eliminate glioma cancer cells but also brings side effects such as anemia. Glutaminyl-peptide cyclotransferase-like protein (QPCTL) catalyzes the pyroglutamylation of CD47 and is crucial for the binding between CD47 and SIRPα. Further study found that loss of intracellular QPCTL limits chemokine function and reshapes myeloid infiltration to augment tumor immunity. However, the role of QPCTL in glioma and the relationship between its expression and clinical outcomes remains unclear. Deciphering the role of QPCTL in glioma will provide a promising therapy for glioma cancer immunotherapy.

Methods

QPCTL expression in glioma tissues and normal adjacent tissues was primarily analyzed in The Cancer Genome Atlas (TCGA) database, and further validated in another independent cohort from the Gene Expression Omnibus (GEO) database, Chinese Glioma Genome Atlas (CGGA), and Human Protein Atlas (HPA). The relationships between QPCTL expression and clinicopathologic parameters and overall survival (OS) were assessed using multivariate methods and Kaplan-Meier survival curves. And the proteins network with which QPCTL interacted was built using the online STRING website. Meanwhile, we use Tumor Immune Estimation Resource (TIMER) and Gene Expression Profiling Interactive Analysis (GEPIA) databases to investigate the relationships between QPCTL expression and infiltrated immune cells and their corresponding gene marker sets. We analyzed the Differentially Expressed Genes (DEGs) including GO/KEGG and Gene Set Enrichment Analysis (GSEA) based on QPCTL-high and -low expression tumors.

Results

In contrast to normal tissue, QPCTL expression was higher in glioma tumor tissue (p < 0.05). Higher QPCTL expression was closely associated with high-grade malignancy and advanced tumor stage. Univariate and multivariate analysis indicated the overall survival of glioma patients with higher QPCTL expression is shorter than those with lower QPCTL expression (p < 0.05). Glioma with QPCTL deficiency presented the paucity of infiltrated immune cells and their matching marker sets. Moreover, QPCTL is essential for glioma cell proliferation and tumor growth and is a positive correlation with glioma cell stemness.

Conclusion

High QPCTL expression predicts high grades of gliomas and poor prognosis with impaired infiltration of adaptive immune cells in the tumor microenvironment as well as higher cancer stemness. Moreover, targeting QPCTL will be a promising immunotherapy in glioma cancer treatment.

Co-Delivery of Dexamethasone and Captopril by α8 Integrin Antibodies Modified Liposome-PLGA Nanoparticle Hybrids for Targeted Anti-Inflammatory/Anti-Fibrosis Therapy of Glomerulonephritis

Purpose

Mesangial cells-mediated glomerulonephritis refers to a category of immunologically mediated glomerular injuries characterized by infiltration of circulating inflammatory cells, proliferation of mesangial cells, and the common pathological manifestation to the later stage is renal fibrosis, accompanied by excessive accumulation of extracellular matrix (ECM). Treatment regimens include glucocorticoids and immunosuppressive agents, but their off-target distribution causes severe systemic toxicity. Hence, specific co-delivery of “anti-inflammatory/anti-fibrosis” drugs to the glomerular mesangial cell (MC) region is expected to produce better therapeutic effects.

Methods

A novel kidney-targeted nanocarrier drug delivery system targeting MCs was constructed using passive targeting resulting from the difference in pore size between the glomerular endothelial layer and the basement membrane, and active targeting based on the specific binding of antibodies and antigens. Specifically, a liposome-nanoparticle hybrid (PLGA-LNHy) was formed by coating the surface of PLGA nanoparticles (NPs) with a phospholipid bilayer, and then PLGA-LNHy was co-modified with PEG and α8 integrin antibodies to obtain PLGA immunoliposomes (PLGA-ILs).

Results

The results showed that the obtained NPs had a core-shell structure, uniform and suitable particle size (119.1 ± 2.31 nm), low cytotoxicity, and good mesangial cell-entry ability, which can successfully accumulate in the glomerular MC region. Both dexamethasone (DXMS) and captopril (CAP) were loaded onto PLGA-ILs with a drug loading of 10.22 ± 1.00% for DXMS and 6.37 ± 0.25% for CAP (DXMS/CAP@PLGA-ILs). In vivo pharmacodynamics showed that DXMS/CAP@PLGA-ILs can effectively improve the pathological changes in the mesangial area and positive expression of proliferating cell nuclear antigen (PCNA) in glomeruli as well as reduce the expression of inflammatory factors, fibrotic factors and reactive oxygen species (ROS). Thus, renal inflammation and fibrosis were relieved.

Conclusion

We have provided a strategy to increase nanoparticle accumulation in MCs with the potential to implement regulatory effects of anti-inflammatory and anti-fibrosis in glomerulonephritis (GN).

A patent review of glutaminyl cyclase inhibitors (2004-present)

Introduction: Glutaminyl cyclase (QC) enzymes catalyze the post-translational processing of several substrates with N-terminal glutamine or glutamate to form pyroglutamate (pE) residue. In addition to physiological functions, emerging evidence demonstrates that human QCs play a part in pathological processes in diverse diseases such as Alzheimer's disease (AD), inflammatory and cancer diseases.Areas covered: In recent years, efforts to effectively develop QC small-molecule inhibitors have been made and different chemical classes have been disclosed. This review summarizes the patents/applications regarding QC inhibitors released from 2004 (first patent) to now. The patents are mostly described in terms of chemical structures, biochemical/pharmacological activities, and potential clinical applications.Expert opinion: For more than 15 years of research, the knowledge on the QC activity domain has considerably increased and therapeutic potential of QC inhibitors has been explored. An important number of studies and patents have been published to expand the use of QC inhibitors. QC enzymes are pharmacologically interesting targets to be used as an AD-modifying therapy, or for other QC-associated disorder. Distinct classes of chemical scaffolds and potential clinical uses have been claimed by various organizations. For the coming years, there is much to experience in the QC field.