Metalloproteinases TACE and MMP-9 Differentially Regulate Death Factors on Adult and Neonatal Monocytes After Infection with Escherichia coli

Design, synthesis, in vitro and in vivo evaluation and molecular docking study of novel pleuromutilin derivatives as antibacterial agents

14 novel pleuromutilin derivatives were designed and synthesized as inhibitors against Staphylococcus aureus (S. aureus). The modification was focused on the C22 position of pleuromutilin. We conducted the characterization, in vitro and in vivo biological assessment of the compounds. Compound 18 exhibited the best antibacterial effect against MRSA (MIC = 0.015 μg/mL, MBC = 0.125 μg/mL). Compound 18 was further studied by time-kill kinetic and post-antibiotic effect (PAE) approaches. Besides, most compounds exhibited low cytotoxicity to RAW 264.7 cells. Compound 18 displayed decent bactericidal activity in vivo (-0.51 log10 CFU/mL). Molecular docking study indicated that compound 18 could be located stably at the ribosome (ΔGb = -7.30 kcal/mol). The results revealed that compound 18 might be further developed into a novel antibiotic.

EBV promotes TCR-T-cell therapy resistance by inducing CD163+M2 macrophage polarization and MMP9 secretion

BACKGROUND

Epstein-Barr virus (EBV) is a double-stranded DNA oncogenic virus. Several types of solid tumors, such as nasopharyngeal carcinoma, EBV-associated gastric carcinoma, and lymphoepithelioma-like carcinoma of the lung, have been linked to EBV infection. Currently, several TCR-T-cell therapies for EBV-associated tumors are in clinical trials, but due to the suppressive immune microenvironment of solid tumors, the clinical application of TCR-T-cell therapy for EBV-associated solid tumors is limited. Figuring out the mechanism by which EBV participates in the formation of the tumor immunosuppressive microenvironment will help T cells or TCR-T cells break through the limitation and exert stronger antitumor potential.

METHODS

Flow cytometry was used for analyzing macrophage differentiation phenotypes induced by EBV-infected and EBV-uninfected tumors, as well as the function of T cells co-cultured with these macrophages. Xenograft model in mice was used to explore the effects of M2 macrophages, TCR-T cells, and matrix metalloprotein 9 (MMP9) inhibitors on the growth of EBV-infected tumors.

RESULTS

EBV-positive tumors exhibited an exhaustion profile of T cells, despite the presence of a large T-cell infiltration. EBV-infected tumors recruited a large number of mononuclear macrophages with CCL5 and induced CD163+M2 macrophages polarization through the secretion of CSF1 and the promotion of autocrine IL10 production by mononuclear macrophages. Massive secretion of MMP9 by this group of CD163+M2 macrophages induced by EBV infection was an important factor contributing to T-cell exhaustion and TCR-T-cell therapy resistance in EBV-positive tumors, and the use of MMP9 inhibitors improved the function of T cells cocultured with M2 macrophages. Finally, the combination of an MMP9 inhibitor with TCR-T cells targeting EBV-positive tumors significantly inhibited the growth of xenografts in mice.

CONCLUSIONS

MMP9 inhibitors improve TCR-T cell function suppressed by EBV-induced M2 macrophages. TCR-T-cell therapy combined with MMP9 inhibitors was an effective therapeutic strategy for EBV-positive solid tumors.

Development of an artificial intelligence-based multimodal model for assisting in the diagnosis of necrotizing enterocolitis in newborns: a retrospective study

Objective

The purpose of this study is to develop a multimodal model based on artificial intelligence to assist clinical doctors in the early diagnosis of necrotizing enterocolitis in newborns.

Methods

This study is a retrospective study that collected the initial laboratory test results and abdominal x-ray image data of newborns (non-NEC, NEC) admitted to our hospital from January 2022 to January 2024.A multimodal model was developed to differentiate multimodal data, trained on the training dataset, and evaluated on the validation dataset. The interpretability was enhanced by incorporating the Gradient-weighted Class Activation Mapping (GradCAM) analysis to analyze the attention mechanism of the multimodal model, and finally compared and evaluated with clinical doctors on external datasets.

Results

The dataset constructed in this study included 11,016 laboratory examination data from 408 children and 408 image data. When applied to the validation dataset, the area under the curve was 0.91, and the accuracy was 0.94. The GradCAM analysis shows that the model's attention is focused on the fixed dilatation of the intestinal folds, intestinal wall edema, interintestinal gas, and portal venous gas. External validation demonstrated that the multimodal model had comparable accuracy to pediatric doctors with ten years of clinical experience in identification.

Conclusion

The multimodal model we developed can assist doctors in early and accurate diagnosis of NEC, providing a new approach for assisting diagnosis in underdeveloped medical areas.

The Endothelial Glycocalyx and Neonatal Sepsis

Sepsis carries a substantial risk of morbidity and mortality in newborns, especially preterm-born neonates. Endothelial glycocalyx (eGC) is a carbohydrate-rich layer lining the vascular endothelium, with important vascular barrier function and cell adhesion properties, serving also as a mechano-sensor for blood flow. eGC shedding is recognized as a fundamental pathophysiological process generating microvascular dysfunction, which in turn contributes to multiple organ failure and death in sepsis. Although the disruption of eGC and its consequences have been investigated intensively in the adult population, its composition, development, and potential mechanisms of action are still poorly studied during the neonatal period, and more specifically, in neonatal sepsis. Further knowledge on this topic may provide a better understanding of the molecular mechanisms that guide the sepsis pathology during the neonatal period, and would increase the usefulness of endothelial glycocalyx dysfunction as a diagnostic and prognostic biomarker. We reviewed several components of the eGC that help to deeply understand the mechanisms involved in the eGC disruption during the neonatal period. In addition, we evaluated the potential of eGC components as biomarkers and future targets to develop therapeutic strategies for neonatal sepsis.

Role of metalloproteases in the CD95 signaling pathways

CD95L (also known as FasL or CD178) is a member of the tumor necrosis family (TNF) superfamily. Although this transmembrane ligand has been mainly considered as a potent apoptotic inducer in CD95 (Fas)-expressing cells, more recent studies pointed out its role in the implementation of non-apoptotic signals. Accordingly, this ligand has been associated with the aggravation of inflammation in different auto-immune disorders and in the metastatic occurrence in different cancers. Although it remains to decipher all key factors involved in the ambivalent role of this ligand, accumulating clues suggest that while the membrane bound CD95L triggers apoptosis, its soluble counterpart generated by metalloprotease-driven cleavage is responsible for its non-apoptotic functions. Nonetheless, the metalloproteases (MMPs and ADAMs) involved in the CD95L shedding, the cleavage sites and the different stoichiometries and functions of the soluble CD95L remain to be elucidated. To better understand how soluble CD95L triggers signaling pathways from apoptosis to inflammation or cell migration, we propose herein to summarize the different metalloproteases that have been described to be able to shed CD95L, their cleavage sites and the biological functions associated with the released ligands. Based on these new findings, the development of CD95/CD95L-targeting therapeutics is also discussed.

Design, synthesis, antibacterial activity evaluation and molecular docking study of pleuromutilin derivatives bearing amide side chains

A seize of pleuromutilin derivatives containing amide side chains were designed and synthesized as potential antibiotics against Methicillin-resistant Staphylococcus aureus (MRSA). Among all target compounds (compounds 11-30), compound 25 was found to have the strongest antibacterial activity against MRSA (minimum inhibitory concentration = 0.5 μg/ml). The result of the time-kill curves indicated that compound 25 could repress the growth of MRSA in vitro obviously (-3.72 log10 CFU/ml reduction). Furthermore, molecular docking studies demonstrated that compound 25 was localized in the binding pocket of 50S ribosomal subunit (ΔGb = -8.99 kcal/mol). Besides, compound 25 displayed low cytotoxicity to RAW 264.7 cells. The results suggested that compound 25 might be further developed into a novel antimicrobial agent against MRSA.

Melatonin pretreatment modulates anti-inflammatory, antioxidant, YKL-40, and matrix metalloproteinases in endotoxemic rat lung tissue

We aimed to investigate the effects of melatonin administered before and during endotoxemia on the lung tissue of rats, cytokine, YKL-40, matrix metalloproteinase (MMP) and inhibitor levels, oxidative stress parameters, and energy balance. Sepsis was induced with lipopolysaccharide (LPS), the cell wall molecule of gram negative bacteria. Rats were divided into four groups, Control, LPS (Escherichia coli O127:B8, 20 mg/kg), melatonin (10 mg/kg), and melatonin+LPS (M+LPS). After injections, lung tissues samples were taken for experimental analyses. YKL-40, thiobarbituric acid reactive substances (TBARS), glutathione reductase (GR), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) enzymes levels were measured, high-energy components were analyzed; tumor necrosis factor-alpha (TNF-α), MMP-2, YKL-40, MMP-9, myeloperoxidase (MPO), tissue inhibitors of matrix metalloproteinase (TIMP)-1, and interleukin (IL)-10 immunoreactivities were investigated. In LPS group, YKL-40, creatine phosphate (both, p < 0.05), SOD, GR, adenosine mono-phophate (AMP), adenosine tri-phosphate (ATP) (for all, p < 0.01) were significantly decreased, while TBARS and adenosine di-phosphate (ADP) levels were increased (p < 0.01, p < 0.05; respectively) compared to other groups. MMP-2 and -9, TIMP-1, TNF-α, IL-10, and MPO immunoreactivity were investigated in LPS group. On the contrary, in M+LPS group, MMP-9, TIMP-1 immunoreactivities were not found and IL-10 and MMP-2 immunoreactivities were found with little involvement. In M+LPS group, YKL-40, GR, AMP, ATP, creatine phosphate (for all, p < 0.05), and SOD (p < 0.01) levels were significantly increased and TBARS levels were decreased (p < 0.05). In our study, we suggest that melatonin exerts a protective and curative effect by reducing the matrix metalloproteinase levels responsible for tissue damage balance, stimulating the release of antioxidant enzymes, regulating cytokines and energy balance during endotoxemia.

MMP9: A Tough Target for Targeted Therapy for Cancer

Having the capability to proteolyze diverse structural and signaling proteins, matrix metalloproteinase 9 (MMP9), one of the best-studied secretory endopeptidases, has been identified as a crucial mediator of processes closely associated with tumorigenesis, such as the extracellular matrix reorganization, epithelial to mesenchymal transition, cell migration, new blood vessel formation, and immune response. In this review, we present the current state of knowledge on MMP9 and its role in cancer growth in the context of cell adhesion/migration, cancer-related inflammation, and tumor microenvironment formation. We also summarize recent achievements in the development of selective MMP9 inhibitors and the limitations of using them as anticancer drugs.

Design, synthesis, in vitro and in vivo evaluation against MRSA and molecular docking studies of novel pleuromutilin derivatives bearing 1, 3, 4-oxadiazole linker

A class of pleuromutilin derivatives containing 1, 3, 4-oxadiazole were designed and synthesized as potential antibacterial agents against Methicillin-resistant staphylococcus aureus (MRSA). The ultrasound-assisted reaction was proposed as a green chemistry method to synthesize 1, 3, 4-oxadiazole derivatives (intermediates 85-110). Among these pleuromutilin derivatives, compound 133 was found to be the strongest antibacterial derivative against MRSA (MIC = 0.125 μg/mL). Furthermore, the result of the time-kill curves displayed that compound 133 could inhibit the growth of MRSA in vitro quickly (- 4.36 log10 CFU/mL reduction). Then, compound 133 (- 1.82 log10 CFU/mL) displayed superior in vivo antibacterial efficacy than tiamulin (- 0.82 log10 CFU/mL) in reducing MRSA load in mice thigh model. Besides, compound 133 exhibited low cytotoxicity to RAW 264.7 cells. Molecular docking studies revealed that compound 133 was successfully localized in the binding pocket of 50S ribosomal subunit (ΔGb = -10.50 kcal/mol). The results indicated that these pleuromutilin derivatives containing 1, 3, 4-oxadiazole might be further developed into novel antibiotics against MRSA.

Matrix Metalloproteinases: How Much Can They Do?

Zinc-dependent matrix metalloproteinases (MMPs) belong to metzincins that comprise not only 23 human MMPs but also other metalloproteinases, such as 21 human ADAMs (a disintegrin and metalloproteinase domain) and 19 secreted ADAMTSs (a disintegrin and metalloproteinase thrombospondin domain). The many setbacks from the clinical trials of broad-spectrum MMP inhibitors for cancer indications in the late 1990s emphasized the extreme complexity of the participation of these proteolytic enzymes in biology. This editorial mini-review summarizes the Special Issue, which includes four review articles and 10 original articles that highlight the versatile roles of MMPs, ADAMs, and ADAMTSs, in normal physiology as well as in neoplastic and destructive processes in tissue. In addition, we briefly discuss the unambiguous involvement of MMPs in wound healing.