Modulation of Neuro-Inflammatory Signals in Microglia by Plasma Prekallikrein and Neuronal Cell Debris

Microglia, the resident phagocytes of the central nervous system and one of the key modulators of the innate immune system, have been shown to play a major role in brain insults. Upon activation in response to neuroinflammation, microglia promote the release of inflammatory mediators as well as promote phagocytosis. Plasma prekallikrein (PKall) has been recently implicated as a mediator of neuroinflammation; nevertheless, its role in mediating microglial activation has not been investigated yet. In the current study, we evaluate the mechanisms through which PKall contributes to microglial activation and release of inflammatory cytokines assessing PKall-related receptors and their dynamics. Murine N9-microglial cells were exposed to PKall (2.5 ng/ml), lipopolysaccharide (100 ng/ml), bradykinin (BK, 0.1 μM), and neuronal cell debris (16.5 μg protein/ml). Gene expression of bradykinin 2 receptor (B2KR), protease-activated receptor 2 (PAR-2), along with cytokines and fibrotic mediators were studied. Bioinformatic analysis was conducted to correlate altered protein changes with microglial activation. To assess receptor dynamics, HOE-140 (1 μM) and GB-83 (2 μM) were used to antagonize the B2KR and PAR-2 receptors, respectively. Also, the role of autophagy in modulating microglial response was evaluated. Data from our work indicate that PKall, LPS, BK, and neuronal cell debris resulted in the activation of microglia and enhanced expression/secretion of inflammatory mediators. Elevated increase in inflammatory mediators was attenuated in the presence of HOE-140 and GB-83, implicating the engagement of these receptors in the activation process coupled with an increase in the expression of B2KR and PAR-2. Finally, the inhibition of autophagy significantly enhanced the release of the cytokine IL-6 which were validated via bioinformatics analysis demonstrating the role of PKall in systematic and brain inflammatory processes. Taken together, we demonstrated that PKall can modulate microglial activation via the engagement of PAR-2 and B2KR where PKall acts as a neuromodulator of inflammatory processes.

Eicosanoid regulation of debris-stimulated metastasis

Cancer therapy reduces tumor burden via tumor cell death (“debris”), which can accelerate tumor progression via the failure of inflammation resolution. Thus, there is an urgent need to develop treatment modalities that stimulate the clearance or resolution of inflammation-associated debris. Here, we demonstrate that chemotherapy-generated debris stimulates metastasis by up-regulating soluble epoxide hydrolase (sEH) and the prostaglandin E2 receptor 4 (EP4). Therapy-induced tumor cell debris triggers a storm of proinflammatory and proangiogenic eicosanoid-driven cytokines. Thus, targeting a single eicosanoid or cytokine is unlikely to prevent chemotherapy-induced metastasis. Pharmacological abrogation of both sEH and EP4 eicosanoid pathways prevents hepato-pancreatic tumor growth and liver metastasis by promoting macrophage phagocytosis of debris and counterregulating a protumorigenic eicosanoid and cytokine storm. Therefore, stimulating the clearance of tumor cell debris via combined sEH and EP4 inhibition is an approach to prevent debris-stimulated metastasis and tumor growth.

Removal of Aflatoxin B1 by Edible Mushroom-Forming Fungi and Its Mechanism

Aflatoxins (AFs) are biologically active toxic metabolites, which are produced by certain toxigenic Aspergillus sp. on agricultural crops. In this study, five edible mushroom-forming fungi were analyzed using high-performance liquid chromatography fluorescence detector (HPLC-FLD) for their ability to remove aflatoxin B1 (AFB1), one of the most potent naturally occurring carcinogens known. Bjerkandera adusta and Auricularia auricular-judae showed the most significant AFB1 removal activities (96.3% and 100%, respectively) among five strains after 14-day incubation. The cell lysate from B. adusta exhibited higher AFB1 removal activity (35%) than the cell-free supernatant (13%) after 1-day incubation and the highest removal activity (80%) after 5-day incubation at 40 °C. In addition, AFB1 analyses using whole cells, cell lysates, and cell debris from B. adusta showed that cell debris had the highest AFB1 removal activity at 5th day (95%). Moreover, exopolysaccharides from B. adusta showed an increasing trend (24–48%) similar to whole cells and cell lysates after 5- day incubation. Our results strongly suggest that AFB1 removal activity by whole cells was mainly due to AFB1 binding onto cell debris during early incubation and partly due to binding onto cell lysates along with exopolysaccharides after saturation of AFB1 binding process onto cell wall components.

Can expelled cells/debris from a developing embryo be used for PGT?

Background Preimplantation genetic testing (PGT) is offered to a wide range of structural and numerical chromosomal imbalances, with PGT- polymerase chain reaction (PCR), as the method of choice for amplifying the small DNA content achieved from the blastomere biopsy or trophectoderm (TE) biopsy, that might have a detrimental impact on embryonic implantation potential. Since human embryos cultured until Day-5–6 were noticed to expel cell debris/ fragments within the zona pellucida, we aimed to examine whether these cell debris/ fragments might be used for PGT, as an alternative to embryo biopsy. Methods Blastocysts, which their Day-3 blastomere biopsy revealed an affected embryo with single-gene defect, and following hatching leaved cell debris/fragments within the zona pellucida were analyzed. Each blastocyst and its corresponding cell debris/fragments were separated and underwent the same molecular analysis, based on multiplex PCR programs designed for haplotyping using informative microsatellites markers. The main outcome measure was the intra-embryo congruity of Day-3 blastomere biopsy and its corresponding blastocyst and cell debris/fragments. Results Fourteen affected embryos from 9 women were included. Only 8/14 (57.2%) of embryos demonstrated congruent molecular genetic results between Day-3 embryo and its corresponding blastocyst and cell debris/fragments. In additional 6/14 (42.8%) embryos, molecular results of the Day-3 embryos and their corresponding blastocysts were congruent, while the cell debris/fragments yielded no molecular diagnoses (incomplete diagnoses). Conclusions It might be therefore concluded, that in PGT cycles, examining the cell debris/fragments on Day-4, instead of Day-3 blastomere or Day-5 TE biopsies, is feasible and might avoid embryo biopsy with its consequent detrimental effect on embryos’ implantation potential. Whenever the latter results in incomplete diagnosis, TE biopsy should be carried out on Day-5 for final genetic results. Further large well-designed studies are required to validate the aforementioned PGT platform.

Role Of Efferocytosis In Oral Lichen Planus

Background: Oral lichen planus (OLP) is a chronic, immune mediated interface mucositis of oral mucosa. Though the apoptosis of keratinocytes is a feature of OLP, not much is known about the clearance of cell debris (efferocytosis) resulting from apoptosis. We postulate that there is a defective or delayed efferocytosis in OLP, which may have a role in modulating the immune response in OLP. Methods: Published mRNA expression of tissue of 14 patients with OLP and 14 cases of normal tissues were subjected to differential analysis (DE) and a list of DE genes identified. From this list, the genes that involved in efferocytosis were collated, compared and their interactions are typed. Result: In all, two studies fulfilled the inclusion and exclusion criteria. On combining the data, 1486 genes were significantly different between OLP and normal tissues. 28 of these 1486 genes are were associated with efferocytosis of which the suppression of LRP1, LDLR, ANAX2, C2, PBX1, PDCD4, S1PR5, CX3CL1, STAT6 and Wnt3A is indicative of defective or delayed efferocytosis in OLP. The role of pathways and associations were analyzed and is presented here. Discussion and Conclusion: The study revealed that certain key genes mRNAs that are associated with efferocytosis are altered in OLP. They could delay or lead to defective efferocytosis. Studying such genes in detail could provide deeper understanding of the pathogenesis of the disease and the discovery of therapeutic targets.

Systematic Literature Review: The Effectiveness of giving Cinnamon (Cinnamon) on Reducing the Intensity of Menstrual Pain (Dysmenorrhea)

Every woman experiences menstruation, which is the process of releasing blood, mucus, and cell debris from the dissertation of the uterine mucosa by removing the endometrium (desquamation) periodically and cyclically. It begins about 14 days after ovulation. Sometimes menstruation causes pain (primary dysmenorrhea) during menstruation. Primary dysmenorrhea can be reduced with natural ingredients, one of which is cinnamon, which has the main compounds cinnamaldehyde and eugenol as anti-inflammatory and antispasmodic. This study aimed to determine the effectiveness of cinnamon in reducing the intensity of menstrual pain (dysmenorrhea). The method used Systematic Literature Review or SLR to analyze articles from some databases The results showed that eight from ten studies were researched with the intervention group (cinnamon) and two journals were descriptive studies. Eight cinnamon intervention groups, three used pills, two used aromatherapy massage, one used cinnamon tea, one used cinnamon extract, and one did not explain the method. All journals show that cinnamon is effective for reducing the intensity of dysmenorrhea.

Effect of Aflatoxin Contaminated Feed for 40 Days on Anatomy and Histopathology of the Thymus of Laying Hens in the Starter Phase

The purpose of this study was to determine the effect of aflatoxin contaminated feed given for 40 days on the anatomy and histopathology of the thymus of laying hens in the starter phase. A total of 36 DOC laying hens were divided into two groups (P0 and P1). P0 (control group) was given 100% basal starter feed CP 521 and P1 (treatment group) was given 80% basal feed CP 524 plus 20% aflatoxin contaminated feed. Feeding contaminated with aflatoxin was carried out for 40 days, starting on the 20th to the 60th day after the DOC of laying hens was adapted for 20 days. The time of surgery in this study was carried out on the 20th, 40th, and 60th days, where at each surgery time the thymus organ was taken to collect weight data and histopathological preparations were made. The thymus weights based on time showed a significant decrease, but the intergroup thymus weights did not show a significant decrease. The decrease in thymus weight is caused by the involution process. Microscopic observations based on increased cell debris and congestion showed that P0 did not show a significant difference, but P1 showed a significant difference (p>0.05) on the 40th and 60th days. The conclusion in this study was that as much as 20% of feed contaminated with aflatoxins had not affected changes in thymus weight but had shown damage to the histopathological structure of the thymus.

Novel RNAi-Based Therapies for Atherosclerosis

Purpose of Review Atherosclerosis, defined by inflammation and accumulation of cholesterol, extracellular matrix, and cell debris into the arteries is a common factor behind cardiovascular diseases (CVD), such as coronary artery disease, peripheral artery disease, and stroke. In this review, we discuss and describe novel RNA interference (RNAi)-based therapies in clinical trials and on the market. Recent Findings The first RNAi-based therapies have entered clinical use for the control of atherosclerosis risk factors, i.e., blood cholesterol levels. The most advanced treatment is silencing of proprotein convertase subtilisin/kexin type 9 (PCSK9) with a drug called inclisiran, which has been approved for the treatment of hypercholesterolemia in late 2020, and results in a robust decrease in plasma cholesterol levels. Summary As the new RNAi therapies for atherosclerosis are now entering markets, the usefulness of these therapies will be further evaluated in larger patient cohorts. Thus, it remains to be seen how fast, effectively and eminently these new drugs consolidate their niche within the cardiovascular disease drug palette.

TAM kinase signaling is indispensable for proper skeletal muscle regeneration in mice

Skeletal muscle regeneration following injury results from the proliferation and differentiation of myogenic stem cells, called satellite cells, located beneath the basal lamina of the muscle fibers. Infiltrating macrophages play an essential role in the process partly by clearing the necrotic cell debris, partly by producing cytokines that guide myogenesis. Infiltrating macrophages are at the beginning pro-inflammatory, but phagocytosis of dead cells induces a phenotypic change to become healing macrophages that regulate inflammation, myoblast fusion and growth, fibrosis, vascularization and return to homeostasis. The TAM receptor kinases Mer and Axl are known efferocytosis receptors in macrophages functioning in tolerogenic or inflammatory conditions, respectively. Here we investigated their involvement in the muscle regeneration process by studying the muscle repair following cardiotoxin-induced injury in Mer−/− mice. We found that Axl was the only TAM kinase receptor expressed on the protein level by skeletal muscle and C2C12 myoblast cells, while Mer was the dominant TAM kinase receptor in the CD45+ cells, and its expression significantly increased during repair. Mer ablation did not affect the skeletal muscle weight or structure, but following injury it resulted in a delay in the clearance of necrotic muscle cell debris, in the healing phenotype conversion of macrophages and consequently in a significant delay in the full muscle regeneration. Administration of the TAM kinase inhibitor BMS-777607 to wild type mice mimicked the effect of Mer ablation on the muscle regeneration process, but in addition, it resulted in a long-persisting necrotic area. Finally, in vitro inhibition of TAM kinase signaling in C2C12 myoblasts resulted in decreased viability and in impaired myotube growth. Our work identifies Axl as a survival and growth receptor in the mouse myoblasts, and reveals the contribution of TAM kinase-mediated signaling to the skeletal muscle regeneration both in macrophages and in myoblasts.

Phagocytic Glial Cells in Brain Homeostasis

Phagocytosis by glial cells has been shown to play an important role in maintaining brain homeostasis. Microglia are currently considered to be the major phagocytes in the brain parenchyma, and these cells phagocytose a variety of materials, including dead cell debris, abnormally aggregated proteins, and, interestingly, the functional synapses of living neurons. The intracellular signaling mechanisms that regulate microglial phagocytosis have been studied extensively, and several important factors, including molecules known as “find me” signals and “eat me” signals and receptors on microglia that are involved in phagocytosis, have been identified. In addition, recent studies have revealed that astrocytes, which are another major glial cell in the brain parenchyma, also have phagocytic abilities. In this review, we will discuss the roles of microglia and astrocytes in phagocytosis-mediated brain homeostasis, focusing on the characteristics and differences of their phagocytic abilities.