Hemin Prevents Increased Glycolysis in Macrophages upon Activation: Protection by Microbiota-Derived Metabolites of Polyphenols

Developing an in vitro model of haematoma for study of intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is a devastating neurovascular attack with limited treatment options. Alternative, pre-clinical modelling approaches are required to identify and trial therapeutic drug compounds. In this study we have used alginate hydrogels to model blood insult in vitro. Human whole blood was mixed with alginate and encapsulated into hydrogel beads. Beads were then incorporated in a second layer of alginate containing hyaluronic acid/chitosan nanoparticles to mimic the mechanical properties of brain tissue and create a model haematoma. Beads and model haematomas were characterised to profile size, volume, mechanical properties, release capacity and storage stability over time. Beads and model haematomas stimulate a pro-inflammatory phenotype in human monocytic and macrophage-like cells, however have no pathogenic effect on brain endothelial and neuronal cell survival or function. In conclusion, we have developed an effective strategy to model ICH in vitro, to investigate the human immune response to blood insult.

Acute intermittent porphyria complicated with acute pancreatitis: A case report and literature review

RATIONALE

Acute intermittent porphyria (AIP) is a rare genetic disorder that affects porphyrin metabolism in the blood. The disease causes defects in specific enzymes in the body, which in turn leads to the accumulation of porphyrin metabolites. Patients may experience abdominal pain, neurological symptoms, muscle pain, and nausea, but it does not directly cause pancreatitis.

PATIENT CONCERNS

The patient is a young woman, 23 years old, who was admitted to our hospital with intermittent abdominal pain for 2 days, the pain was not fixed, episodic, with no obvious trigger, and 1 day before admission, the patient started to experience nausea and vomiting, with gastric contents as the vomitus, and similar symptoms had occurred many times in the past. Blood amylase 600 U/L, blood sodium 120.6 mmol/L, blood routine, and coagulation function results were normal; abdominal CT showed pancreatic swelling with unclear surrounding fat interstitial, acute pancreatitis was considered. The patient's urine was dark red, and the results of the qualitative urine porphyrin test were positive.

DIAGNOSES

AIP complicated with acute pancreatitis.

INTERVENTION

Relief of symptoms, control of pain, correction of electrolyte disturbances, and high-carbohydrate therapy.

OUTCOMES

The patient was discharged with complete symptomatic relief after 10 days of high-carbohydrate therapy.

LESSONS

AIP complicated with acute pancreatitis is very rare. Treatment of AIPs aims to control acute attacks and prevent potential triggers.

New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction

A kinetic analysis of the transport assays on the purified rat brain 2-oxoglutarate/malate carrier (OGC) was performed starting from our recent results reporting about a competitive inhibitory behavior of hemin, a physiological porphyrin derivative, on the OGC reconstituted in an active form into proteoliposomes. The newly provided transport data and the elaboration of the kinetic equations show evidence that hemin exerts a mechanism of partially competitive inhibition, coupled with the formation of a ternary complex hemin-carrier substrate, when hemin targets the OGC from the matrix face. A possible interpretation of the provided kinetic analysis, which is supported by computational studies, could indicate the existence of a binding region responsible for the inhibition of the OGC and supposedly involved in the regulation of OGC activity. The proposed regulatory binding site is located on OGC mitochondrial matrix loops, where hemin could establish specific interactions with residues involved in the substrate recognition and/or conformational changes responsible for the translocation of mitochondrial carrier substrates. The regulatory binding site would be placed about 6 Å below the substrate binding site of the OGC, facing the mitochondrial matrix, and would allow the simultaneous binding of hemin and 2-oxoglutarate or malate to different regions of the carrier. Overall, the presented experimental and computational analyses help to shed light on the possible existence of the hemin-carrier substrate ternary complex, confirming the ability of the OGC to bind porphyrin derivatives, and in particular hemin, with possible consequences for the mitochondrial redox state mediated by the malate/aspartate shuttle led by the mitochondrial carriers OGC and AGC.

The Therapeutic Potential of 4-Methoxy-1-methyl-2-oxopyridine-3-carbamide (MMOXC) Derived from Ricinine on Macrophage Cell Lines Infected with Methicillin-Resistant Strains of Staphylococcus aureus

The incidences of methicillin-resistant strains of Staphylococcus aureus (MRSA) and their survival inside the macrophages are the major attributes of the relapsed infections after antimicrobial therapy, and it is a global problem. In this context, we have previously demonstrated 4-methoxy-1-methyl-2-oxopyridine-3-carbamide (MMOXC), a Ricinine derivative exhibiting anti-S. aureus and anti-biofilm characteristics by competitively inhibiting uridine monophosphate kinase (UMPK), UDP-N-acetyl muramyl pentapeptide ligase (Mur-F), and peptidyl deformylase, (PDF). In the present study, the stability of this competitive inhibitor MMOXC was evaluated by showing its ability to remain bound to the active sites of UMPK, Mur-F, and PDF even after increasing the incubation time, temperature, pH, and substrate concentration. On growing MRSA in fewer concentrations of MMOXC, these strains could not attain resistance to MMOXC and at the same time distinct reductions in the expression of UMPK, Mur-F, and PDF genes were noted. In vitro, infective models were generated by infecting MRSA to RAW 264.7 and human monocyte-derived macrophage (hMDM) cell lines. In these infected cell lines, in spite of increased nitric oxide synthase (NOS), NADPH-P450 reductase, superoxide dismutase, catalase, and peroxidase activities, the MRSA survived. At 640 µM/ml, the concentration of MMOXC penetrated into these infected cells and obliterated MRSA. While treating uninfected macrophage cell lines with MMOXC, no appreciable effect was observed indicating that MMOXC is the most suitable drug for the treatment of infections caused by MRSA.

Escherichia coli O88 induces intestinal damage and inflammatory response through the oxidative phosphorylation and ribosome pathway in Pekin ducks

Colibacillosis is one of the major health threats in the poultry industry worldwide. Understanding the pathogenic mechanisms involved in Escherichia coli-induced inflammatory response may lead to the development of new therapies to combat the disease. To address this, a total of 96 1-day-old male lean Pekin ducklings were employed and randomly allocated to two treatments, each with six replicates of eight ducks. Ducks in the experiment group (EG) and the control group (CG) were separately orally administered with 0.2 ml of pathogenic E. coli O88 (3 × 109 CFU/ml) or equivalent volumes of 0.9% sterile saline solution on day 7, two times with an 8-h interval. Serum and intestinal samples were collected on days 9, 14, and 28. Results showed that ducks challenged with E. coli had lower average daily gain and higher feed intake/weight gain during days 9–14 and overall (P < 0.05). Histopathological examination showed that E. coli decreased the villus height and the ratio of villus height/crypt depth in the jejunum (P < 0.05) on days 9 and 14. The intestinal barrier was disrupted, presenting in E. coli ducks having higher serum DAO and D-LA on days 9 and 14 (P < 0.05) and greater content of serum LPS on day 9 (P < 0.05). Escherichia coli infection also triggered a systemic inflammatory response including the decrease of the serum IgA, IgM, and jejunal sIgA on day 14 (P < 0.05). In addition to these, 1,062 differentially expressed genes were detected in the jejunum tissues of ducks by RNA-seq, consisting of 491 upregulated and 571 downregulated genes. Based on the KEGG database, oxidative phosphorylation and the ribosome pathway were the most enriched. These findings reveal the candidate pathways and genes that may be involved in E. coli infection, allow a better understanding of the molecular mechanisms of inflammation progression and may facilitate the genetic improvement of ducks, and provide further insights to tackle the drug sensitivity and animal welfare issues.

Targeting microbiota-host interactions with resveratrol on cancer: Effects and potential mechanisms of action

Resveratrol (RSV) is a natural polyphenolic compound detected in grapes, berries, and red wine. The anticancer activities of RSV have been observed in vivo and in vitro studies. However, the pharmacology mechanism of RSV is confusing due to its low bioavailability. According to studies of the metabolic characteristics of RSV, the gut intestine is a crucial site of its health benefits. Dietary RSV exhibits a profound effect on the gut microbiota structure and metabolic function. In addition, emerging evidence demonstrates a protective effect of RSV metabolites against carcinogenesis. Therefore, to better understand the anticancer mechanisms of dietary RSV, it is vital to evaluate the role of RSV-microbiota-host interactions in cancer therapy. In this review, we summarized significant findings on the anticancer activities of RSV based on epidemiological, experimental and clinical studies involved in investigating the metabolic characteristics and the traditional anticancer mechanisms of RSV. Special attention is given to the putative mechanisms involving microbiota-host interactions, such as the modulation of gut microecology and the anticancer effects of RSV metabolites. The changes in microbiota-host interactions after RSV supplementation play vital roles in cancer prevention and thus offering a new perspective on nutritional interventions to treat cancer.

The Role of Metabolic Plasticity of Tumor-Associated Macrophages in Shaping the Tumor Microenvironment Immunity

Cancer cells possess a high metabolic demand for their rapid proliferation, survival, and progression and thus create an acidic and hypoxic tumor microenvironment (TME) deprived of nutrients. Moreover, acidity within the TME is the central regulator of tumor immunity that influences the metabolism of the immune cells and orchestrates the local and systemic immunity, thus, the TME has a major impact on tumor progression and resistance to anti-cancer therapy. Specifically, myeloid cells, which include myeloid-derived suppressor cells (MDSC), dendritic cells, and tumor-associated macrophages (TAMs), often reprogram their energy metabolism, resulting in stimulating the angiogenesis and immunosuppression of tumors. This review summarizes the recent findings of glucose, amino acids, and fatty acid metabolism changes of the tumor-associated macrophages (TAMs), and how the altered metabolism shapes the TME and anti-tumor immunity. Multiple proton pumps/transporters are involved in maintaining the alkaline intracellular pH which is necessary for the glycolytic metabolism of the myeloid cells and acidic TME. We highlighted the roles of these proteins in modulating the cellular metabolism of TAMs and their potential as therapeutic targets for improving immune checkpoint therapy.

Natural Compounds as Metabolic Modulators of the Tumor Microenvironment

The tumor microenvironment (TME) is a heterogenous assemblage of malignant and non-malignant cells, including infiltrating immune cells and other stromal cells, together with extracellular matrix and a variety of soluble factors. This complex and dynamic milieu strongly affects tumor differentiation, progression, immune evasion, and response to therapy, thus being an important therapeutic target. The phenotypic and functional features of the various cell types present in the TME are largely dependent on their ability to adopt different metabolic programs. Hence, modulating the metabolism of the cells in the TME, and their metabolic crosstalk, has emerged as a promising strategy in the context of anticancer therapies. Natural compounds offer an attractive tool in this respect as their multiple biological activities can potentially be harnessed to ‘(re)-educate’ TME cells towards antitumoral roles. The present review discusses how natural compounds shape the metabolism of stromal cells in the TME and how this may impact tumor development and progression.