Mitofusin 2 Deficiency Causes Pro-Inflammatory Effects in Human Primary Macrophages.
Ontology highlight
ABSTRACT:
SUBMITTER: Khodzhaeva V
PROVIDER: S-EPMC8397414 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Apoptosis is an important host defense mechanism against mycobacterial infection. However, the molecular mechanisms regulating apoptosis during mycobacterial infection are not well known. Recent reports suggest that bacterial infection regulates mitochondrial fusion and fission in various ways. Here, we investigated the role of mitochondria in Mycobacterium tuberculosis (Mtb)-infected macrophages. Mtb H37Rv (Rv) infection induced mitofusin 2 (MFN2) degradation, leading to mitochondrial fission. Interestingly, Mtb H37Ra (Ra) infection induced significantly greater mitochondrial fragmentation than Rv infection. Mtb-mediated Parkin, an E3 ubiquitin ligase, contributed to the degradation of MFN2. To evaluate the role of endoplasmic reticulum stress in the production of Parkin during Mtb infection, we analyzed Parkin production in 4-phenylbutyric acid (4-PBA)-pretreated macrophages. Pretreatment with 4-PBA reduced Parkin production in Mtb-infected macrophages. In contrast, the level of MFN2 production recovered to a level similar to that of the unstimulated control. In addition, Ra-infected macrophages had reduced mitochondrial membrane potential (MMP) compared to those infected with Rv. Interestingly, intracellular survival of mycobacteria was decreased in siMFN2-transfected macrophages; in contrast, overexpression of MFN2 in macrophages increased Mtb growth compared with the control.
| S-EPMC6912353 | biostudies-literature
Project description:Chronic inflammatory disorders such as rheumatoid arthritis are characterized by excessive pro-inflammatory or "M1" activation of macrophages, the primary cells of the innate immune system. Current treatments include delivery of glucocorticoids (e.g. dexamethasone - Dex), which reduce pro-inflammatory M1 behaviour in macrophages. However, these treatments have many off-target effects on cells other than macrophages, resulting in broad immunosuppression. To limit such side effects, drug-incorporated nano- and microparticles may be used to selectively target macrophages via phagocytosis, because of their roles as highly effective phagocytes in the body. In this study, surface-modified nanodiamond (ND) was explored as a platform for the delivery of dexamethasone to macrophages because of ND's rich surface chemistry, which contributes to ND's high potential as a versatile drug delivery platform. After finding that octadecylamine-functionalized nanodiamond (ND-ODA) enhanced adsorption of Dex compared to carboxylated ND, the effects of Dex, ND-ODA, and Dex-adsorbed ND-ODA on primary human macrophage gene expression were characterized. Surprisingly, even in the absence of Dex, ND-ODA had strong anti-inflammatory effects, as determined by multiplex gene expression via NanoString and by protein secretion analysis via ELISA. ND-ODA also inhibited expression of M2a markers yet increased the expression of M2c markers and phagocytic receptors. Interestingly, the adsorption of Dex to ND-ODA further increased some anti-inflammatory effects, but abrogated the effect on phagocytic receptors, compared to its individual components. Overall, the ability of ND-ODA to promote anti-inflammatory and pro-phagocytic behaviour in macrophages, even in the absence of loaded drugs, suggests its potential for use as an anti-inflammatory therapeutic to directly target macrophages through phagocytosis.
| S-EPMC5719499 | biostudies-literature
Project description:BACKGROUND:Airway epithelial cells and alveolar macrophages (AMs) are the first line of defense in the lung during infection. Toll-like receptor (TLR) agonists have been extensively used to define the regulation of inflammation in these cells. However, previous studies were performed in non-paired airway epithelial cells and AMs. The major goal of our study was to compare the pro- and anti-inflammatory responses of paired human primary airway epithelial cells and AMs to TLR3 and TLR4 agonists. METHODS:Tracheobronchial epithelial cells (TBEC) and AMs from four smokers and four non-smokers without lung disease were cultured with or without Poly(I:C) (PIC) (a TLR3 agonist) or LPS (a TLR4 agonist) for 4, 24 and 48 h. The immune responses of paired cells were compared. RESULTS:TBEC and AMs showed stronger pro-inflammatory cytokine (e.g., IL-8) responses to PIC and LPS, respectively. TLR3 and TLR4 mRNA levels were similar in non-stimulated TBEC and AMs. However, PIC stimulation in AMs led to sustained up-regulation of the immune negative regulators Tollip and A20, which may render AMs less sensitive to PIC stimulation than TBEC. Unlike AMs, TBEC did not increase NF-?B activation after LPS stimulation. Interestingly, smoking status was correlated with less TLR3 and IRAK-M expression in non-stimulated TBEC, but not in AMs. PIC-stimulated TBEC and LPS-stimulated AMs from smokers vs. non-smokers produced more IL-8. Finally, we show that expression of A20 and IRAK-M is strongly correlated in the two paired cell types. CONCLUSIONS:By using paired airway epithelial cells and AMs, this study reveals how these two critical types of lung cells respond to viral and bacterial pathogen associated molecular patterns, and provides rationale for modulating immune negative regulators to prevent excessive lung inflammation during respiratory infection.
| S-EPMC6020222 | biostudies-literature
Project description:ARHGEF1 is a RhoA-specific guanine nucleotide exchange factor expressed in hematopoietic cells. We used whole-exome sequencing to identify compound heterozygous mutations in ARHGEF1, resulting in the loss of ARHGEF1 protein expression in 2 primary antibody-deficient siblings presenting with recurrent severe respiratory tract infections and bronchiectasis. Both ARHGEF1-deficient patients showed an abnormal B cell immunophenotype, with a deficiency in marginal zone and memory B cells and an increased frequency of transitional B cells. Furthermore, the patients' blood contained immature myeloid cells. Analysis of a mediastinal lymph node from one patient highlighted the small size of the germinal centers and an abnormally high plasma cell content. On the molecular level, T and B lymphocytes from both patients displayed low RhoA activity and low steady-state actin polymerization (even after stimulation of lysophospholipid receptors). As a consequence of disturbed regulation of the RhoA downstream target Rho-associated kinase I/II (ROCK), the patients' lymphocytes failed to efficiently restrain AKT phosphorylation. Enforced ARHGEF1 expression or drug-induced activation of RhoA in the patients' cells corrected the impaired actin polymerization and AKT regulation. Our results indicate that ARHGEF1 activity in human lymphocytes is involved in controlling actin cytoskeleton dynamics, restraining PI3K/AKT signaling, and confining B lymphocytes and myelocytes within their dedicated functional environment.
| S-EPMC6391114 | biostudies-literature
Project description:It has been observed that the consumption of litchi often causes symptoms characterized by itching or sore throat, gum swelling, oral cavity ulcers and even fever and inflammation, which significantly impair the quality of life of a large population. Using the RAW264.7 cell line, a step-by-step strategy was used to screen for the components in litchi fruits that elicited adverse reactions. The adverse reaction fractions were identified by mass spectrometry and analyzed using the SMART program, and a sequence alignment of the homologous proteins was performed. MTT tests were used to determine the cytotoxicity of a litchi protein extract in RAW264.7 macrophages, and real-time PCR was applied to analyze the expression of inflammatory genes in the RAW264.7 cells treated with lipopolysaccharide or the litchi protein extract. The results showed that the litchi water-soluble protein extract could increase the production of the pro-inflammatory mediators IL-1β, iNOS and COX-2, and the anti-inflammatory mediator HO-1 in the RAW264.7 cell line. The 14-3-3-like proteins GF14 lambda, GF14 omega and GF14 upsilon were likely the candidate proteins that caused the adverse effects.
| S-EPMC4855250 | biostudies-literature
Project description:Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a critical regulator of cell death and inflammation, but its relevance for human disease pathogenesis remains elusive. Studies of monogenic disorders might provide critical insights into disease mechanisms and therapeutic targeting of RIPK1 for common diseases. Here, we report on eight patients from six unrelated pedigrees with biallelic loss-of-function mutations in RIPK1 presenting with primary immunodeficiency and/or intestinal inflammation. Mutations in RIPK1 were associated with reduced NF-κB activity, defective differentiation of T and B cells, increased inflammasome activity, and impaired response to TNFR1-mediated cell death in intestinal epithelial cells. The characterization of RIPK1-deficient patients highlights the essential role of RIPK1 in controlling human immune and intestinal homeostasis, and might have critical implications for therapies targeting RIPK1.
| S-EPMC6338855 | biostudies-other
Project description:Cholestasis is caused by autoimmune reactions, drug-induced hepatotoxicity, viral infections of the liver and the obstruction of bile ducts by tumours or gallstones. Cholestatic conditions are associated with impaired innate and adaptive immunity, including alterations of the cellular functions of monocytes, macrophages, NK cells and T-cells. Bile acids act as signalling molecules, affecting lipopolysaccharide (LPS)-induced cytokine expression in primary human macrophages. The present manuscript investigates the impact of bile acids, such as taurolithocholic acid (TLC), on the transcriptome of human macrophages in the presence or absence of LPS. While TLC itself has almost no effect on gene expression under control conditions, this compound modulates the expression of 202 out of 865 transcripts in the presence of LPS. Interestingly, pathway analysis revealed that TLC specifically supressed the expression of genes involved in mediating pro-inflammatory effects, phagocytosis, interactions with pathogens and autophagy as well as the recruitment of immune cells, such as NK cells, neutrophils and T cells. These data indicate a broad influence of bile acids on inflammatory responses and immune functions in macrophages. These findings may contribute to the clinical observation that patients with cholestasis present a lack of response to bacterial or viral infections.
| S-EPMC5762890 | biostudies-other
Project description:In order to improve the efficacy of conventional radiotherapy, attention has been paid to immune cells, which not only modulate cancer cell response to therapy but are also highly recruited to tumours after irradiation. Particularly, the effect of ionizing radiation on macrophages, using therapeutically relevant doses, is not well understood. To evaluate how radiotherapy affects macrophage behaviour and macrophage-mediated cancer cell activity, human monocyte derived-macrophages were subjected, for a week, to cumulative ionizing radiation doses, as used during cancer treatment (2?Gy/fraction/day). Irradiated macrophages remained viable and metabolically active, despite DNA damage. NF-kappaB transcription activation and increased Bcl-xL expression evidenced the promotion of pro-survival activity. A significant increase of pro-inflammatory macrophage markers CD80, CD86 and HLA-DR, but not CCR7, TNF and IL1B was observed after 10?Gy cumulative doses, while anti-inflammatory markers CD163, MRC1, VCAN and IL-10 expression decreased, suggesting the modulation towards a more pro-inflammatory phenotype. Moreover, ionizing radiation induced macrophage morphological alterations and increased their phagocytic rate, without affecting matrix metalloproteases (MMP)2 and MMP9 activity. Importantly, irradiated macrophages promoted cancer cell-invasion and cancer cell-induced angiogenesis. Our work highlights macrophage ability to sustain cancer cell activities as a major concern that needs to be addressed to improve radiotherapy efficacy.
| S-EPMC4702523 | biostudies-literature
Project description:The Nuclear Factor-kappa B (NF-?B) pathway is vital for immune system regulation and pro-inflammatory signaling. Many inflammatory disorders and diseases, including cancer, are linked to dysregulation of NF-?B signaling. When macrophages recognize the presence of a pathogen, the signaling pathway is activated, resulting in the nuclear translocation of the transcription factor, NF-?B, to turn on pro-inflammatory genes. Here, we demonstrate the effects of a novel microtubule depolymerizer, NT-07-16, a polysubstituted pyrrole compound, on this process. Treatment with NT-07-16 decreased the production of pro-inflammatory cytokines in RAW264.7 mouse macrophages. It appears that the reduction in pro-inflammatory mediators produced by the macrophages after exposure to NT-07-16 may be due to activities upstream of the translocation of NF-?B into the nucleus. NF-?B translocation occurs after its inhibitory protein, I?B-? is phosphorylated which signals for its degradation releasing NF-?B so it is free to move into the nucleus. Previous studies from other laboratories indicate that these processes are associated with the microtubule network. Our results show that exposure to the microtubule-depolymerizer, NT-07-16 reduces the phosphorylation of I?B-? and also decreases the association of NF-?B with tubulin which may affect the ability of NF-?B to translocate into the nucleus. Therefore, the anti-inflammatory activity of NT-07-16 may be explained, at least in part, by alterations in these steps in the NF-?B signaling pathway leading to less NF-?B entering the nucleus and reducing the production of pro-inflammatory mediators by the activated macrophages.
| S-EPMC5766364 | biostudies-literature
Project description:Thrombospondin-4 (TSP-4) attracted renewed attention recently as a result of assignment of new functions to this matricellular protein in cardiovascular, muscular, and nervous systems. We have previously reported that TSP-4 promotes local vascular inflammation in a mouse atherosclerosis model. A common variant of TSP-4, P387-TSP-4, was associated with increased cardiovascular disease risk in human population studies. In a mouse atherosclerosis model, TSP-4 had profound effect on accumulation of macrophages in lesions, which prompted us to examine its effects on macrophages in more detail. We examined the effects of A387-TSP-4 and P387-TSP-4 on mouse macrophages in cell culture and in vivo in the model of LPS-induced peritonitis. In tissues and in cell culture, TSP-4 expression was associated with inflammation: TSP-4 expression was upregulated in peritoneal tissues in LPS-induced peritonitis, and pro-inflammatory signals, INFγ, GM-CSF, and LPS, induced TSP-4 expression in macrophages in vivo and in cell culture. Deficiency in TSP-4 in macrophages from Thbs4-/- mice reduced the expression of pro-inflammatory macrophage markers, suggesting that TSP-4 facilitates macrophage differentiation into a pro-inflammatory phenotype. Expression of TSP-4, especially more active P387-TSP-4, was associated with higher cellular apoptosis. Cultured macrophages displayed increased adhesion to TSP-4 and reduced migration in presence of TSP-4, and these responses were further increased with P387 variant. We concluded that TSP-4 expression in macrophages increases their accumulation in tissues during the acute inflammatory process and supports macrophage differentiation into a pro-inflammatory phenotype. In a model of acute inflammation, TSP-4 supports pro-inflammatory macrophage apoptosis, a response that is closely related to their pro-inflammatory activity and release of pro-inflammatory signals. P387-TSP-4 was found to be the more active form of TSP-4 in all examined functions.
| S-EPMC6978349 | biostudies-literature