Blockage of Fc Gamma Receptors Alleviates Neuronal and Microglial Toxicity Induced by Palmitic Acid

2021 ◽  
pp. 1-18
Author(s):  
Phansa Phitthayaphong ◽  
Sirinart Kumfu ◽  
Nipon Chattipakorn ◽  
Siriporn C. Chattipakorn

Background: Palmitic acid (PA) promotes brain pathologies including Alzheimer’s disease (AD)-related proteins, neuroinflammation, and microglial activation. The activation of neurons and microglia via their Fc gamma receptors (FcγRs) results in producing inflammatory cytokines. Objective: To investigate the expression of FcγRs, FcγR signaling proteins, AD-related proteins, proinflammatory cytokines, and cell viability of neurons and microglia in association with PA exposure as well as the effects of FcγR blockade on these parameters in response to PA. Methods: 200 and 400μM PA-conjugated BSA were applied to SH-SY5Y and HMC3 cells for 24 h. For FcγR blockage experiment, both cells were exposed to FcγR blocker before receiving of 200 and 400μM of PA-conjugated BSA for 24 h. Results: PA significantly increased AD-related proteins, including Aβ and BACE1, as well as increasing TNFα, IL-1β, and IL-6 in SH-SY5Y and HMC3 cells. However, the p-Tau/Tau ratio was only increased in SH-SY5Y cells. These results were associated with an increase in FcγRs activation and a decrease in cell viability in both cell types. FcγRs blockage diminished the activation of FcγR in SH-SY5Y and HMC3 cells. Interestingly, blocking FcγRs before PA exposure reduced the increment of AD-related proteins, proinflammatory cytokines caused by PA. FcγRs blocking also inhibits cell death for 23%of SH-SY5Y cells and 64%of HMC3 cells, respectively. Conclusion: These findings suggest that PA is a risk factor for AD via the increased AD-related pathologies, inflammation, FcγRs activation, and brain cell death, while FcγR blockage can alleviate these effects.

Author(s):  
Kathryn A. Martinello ◽  
Christopher Meehan ◽  
Adnan Avdic-Belltheus ◽  
Ingran Lingam ◽  
Tatenda Mutshiya ◽  
...  

Abstract Background Perinatal inflammation combined with hypoxia–ischemia (HI) exacerbates injury in the developing brain. Therapeutic hypothermia (HT) is standard care for neonatal encephalopathy; however, its benefit in inflammation-sensitized HI (IS-HI) is unknown. Methods Twelve newborn piglets received a 2 µg/kg bolus and 1 µg/kg/h infusion over 52 h of Escherichia coli lipopolysaccharide (LPS). HI was induced 4 h after LPS bolus. After HI, piglets were randomized to HT (33.5 °C 1–25 h after HI, n = 6) or normothermia (NT, n = 6). Amplitude-integrated electroencephalogram (aEEG) was recorded and magnetic resonance spectroscopy (MRS) was acquired at 24 and 48 h. At 48 h, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive brain cell death, microglial activation/proliferation, astrogliosis, and cleaved caspase-3 (CC3) were quantified. Hematology and plasma cytokines were serially measured. Results Two HT piglets died. aEEG recovery, thalamic and white matter MRS lactate/N-acetylaspartate, and TUNEL-positive cell death were similar between groups. HT increased microglial activation in the caudate, but had no other effect on glial activation/proliferation. HT reduced CC3 overall. HT suppressed platelet count and attenuated leukocytosis. Cytokine profile was unchanged by HT. Conclusions We did not observe protection with HT in this piglet IS-HI model based on aEEG, MRS, and immunohistochemistry. Immunosuppressive effects of HT and countering neuroinflammation by LPS may contribute to the observed lack of HT efficacy. Other immunomodulatory strategies may be more effective in IS-HI. Impact Acute infection/inflammation is known to exacerbate perinatal brain injury and can worsen the outcomes in neonatal encephalopathy. Therapeutic HT is the current standard of care for all infants with NE, but the benefit in infants with coinfection/inflammation is unknown. In a piglet model of inflammation (LPS)-sensitized HI, we observed no evidence of neuroprotection with cooling for 24 h, based on our primary outcome measures: aEEG, MRS Lac/NAA, and histological brain cell death. Additional neuroprotective agents, with beneficial immunomodulatory effects, require exploration in IS-HI models.


2010 ◽  
Vol 206 (2) ◽  
pp. 225-233 ◽  
Author(s):  
P A Hill ◽  
A Tumber

Programmed cell death (PCD) or apoptosis is a naturally occurring cell suicide pathway induced in a variety of cell types. We determined whether ceramide treatment contributes to reduced cell viability and increased PCD in primary osteoblasts and the signalling pathways that are involved. Cell viability was determined by the 3-(4,5-dimethyl-thiozol-2-yl)-2,5-diphenyl tetrazolium bromide assay. We found that C2-ceramide (≤10−7 M) promoted osteoblast viability, whilst concentrations ≥2×10−6 M significantly reduced osteoblast viability in a dose- and time-dependent manner. The effect of ceramide on cell viability was specific since C2-dihydroceramide had no effect. Increasing intracellular ceramide levels with either sphingomyelinase (SMase) or an inhibitor of ceramide metabolism also increased osteoblast apoptosis. Ceramide-induced PCD in osteoblasts was determined by nuclear appearance and DNA fragmentation. PCD was induced by both C2-ceramide and SMase. The ability of ceramide (5×10−8 M) to promote osteoblast survival was prevented by a general protein kinase C (PKC) inhibitor and by a PKC ζ inhibitor, whilst osteoblast survival was enhanced in the presence of a protein phosphatase 1 (PP1) inhibitor. Phosphatidylinositol-3 kinase (PI3K) inhibitors had no effect on osteoblast survival. The ability of ceramide (5×10−5 M) to induce apoptosis was prevented by the inhibitors of PP1 and PKC δ, whilst the general PKC and PI3K inhibitors had no effect on it. Our findings suggest that ceramide signals osteoblast survival and apoptosis through different intracellular pathways, and that alteration in the intracellular levels of ceramide may play an important role in bone remodelling.


2019 ◽  
Vol 216 (11) ◽  
pp. 2453-2465 ◽  
Author(s):  
Pontus Orning ◽  
Egil Lien ◽  
Katherine A. Fitzgerald

The gasdermins are a family of pore-forming proteins recently implicated in the immune response. One of these proteins, gasdermin D (GSDMD), has been identified as the executioner of pyroptosis, an inflammatory form of lytic cell death that is induced upon formation of caspase-1–activating inflammasomes. The related proteins GSDME and GSDMA have also been implicated in autoimmune diseases and certain cancers. Most gasdermin proteins are believed to have pore-forming capabilities. The best-studied member, GSDMD, controls the release of the proinflammatory cytokines IL-1ß and IL-18 and pyroptotic cell death. Because of its potential as a driver of inflammation in septic shock and autoimmune diseases, GSDMD represents an attractive drug target. In this review, we discuss the gasdermin proteins with particular emphasis on GSDMD and its mechanism of action and biological significance.


Cells ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 28 ◽  
Author(s):  
Xinfang An ◽  
Zixing Fu ◽  
Chendi Mai ◽  
Weiming Wang ◽  
Linyu Wei ◽  
...  

Human neuroblastoma SH-SY5Y cells are a widely-used human neuronal cell model in the study of neurodegeneration. A recent study shows that, 1-methyl-4-phenylpyridine ion (MPP), which selectively causes dopaminergic neuronal death leading to Parkinson’s disease-like symptoms, can reduce SH-SY5Y cell viability by inducing H2O2 generation and subsequent TRPM2 channel activation. MPP-induced cell death is enhanced by increasing the TRPM2 expression. By contrast, increasing the TRPM2 expression has also been reported to support SH-SY5Y cell survival after exposure to H2O2, leading to the suggestion of a protective role for the TRPM2 channel. To clarify the role of reactive oxygen species (ROS)-induced TRPM2 channel activation in SH-SY5Y cells, we generated a stable SH-SY5Y cell line overexpressing the human TRPM2 channel and examined cell death and cell viability after exposure to H2O2 in the wild-type and TRPM2-overexpressing SH-SY5Y cells. Exposure to H2O2 resulted in concentration-dependent cell death and reduction in cell viability in both cell types. TRPM2 overexpression remarkably augmented H2O2-induced cell death and reduction in cell viability. Furthermore, H2O2-induced cell death in both the wild-type and TRPM2-overexpressing cells was prevented by 2-APB, a TRPM2 inhibitor, and also by PJ34 and DPQ, poly(ADP-ribose) polymerase (PARP) inhibitors. Collectively, our results show that increasing the TRPM2 expression renders SH-SY5Y cells to be more susceptible to ROS-induced cell death and reinforce the notion that the TRPM2 channel plays a critical role in conferring ROS-induced cell death. It is anticipated that SH-SY5Y cells can be useful for better understanding the molecular and signaling mechanisms for ROS-induced TRPM2-mediated neurodegeneration in the pathogenesis of neurodegenerative diseases.


Author(s):  
Chien-An Andy Hu ◽  
Chien-An Andy Hu ◽  
Siqin Zhaorigetu ◽  
W Sean Davidson ◽  
Warren Laskey

We have previously demonstrated that apolipoprotein L6 (ApoL6) is a pro-death, phospholipid-binding, BH3-only member of the Bcl-2 family. Ectopic expression of ApoL6 induces dichotomous cell death phenotype involving both apoptosis and necroptosis in various cell types. In addition, ApoL6 initiates inflammatory response that upregulates proinflammatory cytokines, such as IL-1β. In this study, we show elevated levels of ApoL6 in the sera of the majority of ST-segment myocardial infarction (STEMI) patients prior to reperfusion which is highly suggestive of the activation of apoptotic and/or necroptotic pathways in ruptured plaque. Thus, ApoL6 could serve as a biomarker specific for inflammatory apoptotic and/or necroptotic activity in STEMI, as well as other diseases.


Author(s):  
L. M. Sosedova ◽  
V. S. Rukavishnikov ◽  
E. A. Titov

The results of a study on rats toxicity of nanoparticles of metals bismuth, gadolinium and silver encapsulated in a natural biopolymer matrix arabinogalactan are presented. When intake of nanocomposite of silver revealed the readiness of the brain cell to apoptosis. The effect of bismuth and gadolinium nanocomposites did not cause an increase in the process of programmed cell death.


2019 ◽  
Vol 19 (2) ◽  
pp. 112-119 ◽  
Author(s):  
Mariana B. de Oliveira ◽  
Luiz F.G. Sanson ◽  
Angela I.P. Eugenio ◽  
Rebecca S.S. Barbosa-Dantas ◽  
Gisele W.B. Colleoni

Introduction:Multiple myeloma (MM) cells accumulate in the bone marrow and produce enormous quantities of immunoglobulins, causing endoplasmatic reticulum stress and activation of protein handling machinery, such as heat shock protein response, autophagy and unfolded protein response (UPR).Methods:We evaluated cell lines viability after treatment with bortezomib (B) in combination with HSP70 (VER-15508) and autophagy (SBI-0206965) or UPR (STF- 083010) inhibitors.Results:For RPMI-8226, after 72 hours of treatment with B+VER+STF or B+VER+SBI, we observed 15% of viable cells, but treatment with B alone was better (90% of cell death). For U266, treatment with B+VER+STF or with B+VER+SBI for 72 hours resulted in 20% of cell viability and both treatments were better than treatment with B alone (40% of cell death). After both triplet combinations, RPMI-8226 and U266 presented the overexpression of XBP-1 UPR protein, suggesting that it is acting as a compensatory mechanism, in an attempt of the cell to handle the otherwise lethal large amount of immunoglobulin overload.Conclusion:Our in vitro results provide additional evidence that combinations of protein homeostasis inhibitors might be explored as treatment options for MM.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Na Jiang ◽  
Xiaoyu Zhang ◽  
Xuejun Gu ◽  
Xiaozhuang Li ◽  
Lei Shang

AbstractLong non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides but not translated into proteins. LncRNAs regulate gene expressions at multiple levels, such as chromatin, transcription, and post-transcription. Further, lncRNAs participate in various biological processes such as cell differentiation, cell cycle regulation, and maintenance of stem cell pluripotency. We have previously reported that lncRNAs are closely related to programmed cell death (PCD), which includes apoptosis, autophagy, necroptosis, and ferroptosis. Overexpression of lncRNA can suppress the extrinsic apoptosis pathway by downregulating of membrane receptors and protect tumor cells by inhibiting the expression of necroptosis-related proteins. Some lncRNAs can also act as competitive endogenous RNA to prevent oxidation, thereby inhibiting ferroptosis, while some are known to activate autophagy. The relationship between lncRNA and PCD has promising implications in clinical research, and reports have highlighted this relationship in various cancers such as non-small cell lung cancer and gastric cancer. This review systematically summarizes the advances in the understanding of the molecular mechanisms through which lncRNAs impact PCD.


2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii17-ii17
Author(s):  
Shashank Hambarde ◽  
Martyn Sharpe ◽  
David Baskin ◽  
Santosh Helekar

Abstract Noninvasive cancer therapy with minimal side effects would be ideal for improving patient outcome in the clinic. We have developed a novel therapy using strong rotating magnets mounted on a helmet. They generate oscillating magnetic fields (OMF) that penetrate through the skull and cover the entire brain. We have demonstrated that OMF can effectively kill patient derived glioblastoma (GBM) cells in cell culture without having cytotoxic effects on cortical neurons and normal human astrocytes (NHA). Exposure of GBM cells to OMF reduced the cell viability by 33% in comparison to sham-treated cells (p< 0.001), while not affecting NHA cell viability. Time lapse video-microscopy for 16 h after OMF exposure showed a marked elevation of mitochondrial reactive oxygen species (ROS), and rapid apoptosis of GBM cells due to activation of caspase 3. Addition of a potent antioxidant vitamin E analog Trolox effectively blocked OMF-induced GBM cell death. Furthermore, OMF significantly potentiated the cytotoxic effect of the pro-oxidant Benzylamine. The results of our studies demonstrate that OMF-induced cell death is mediated by ROS generation. These results demonstrate a potent oncolytic effect on GBM cells that is novel and unrelated to any previously described therapy, including a very different mechanism of action and different technology compared to Optune therapy. The effect is very powerful, and unlike Optune, can be seen within hours after initiation of treatment. We believe that this technology holds great promise for new, effective and nontoxic treatment of glioblastoma.


Immuno ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 78-90
Author(s):  
Johannes Burtscher ◽  
Grégoire P. Millet

Like in other neurodegenerative diseases, protein aggregation, mitochondrial dysfunction, oxidative stress and neuroinflammation are hallmarks of Parkinson’s disease (PD). Differentiating characteristics of PD include the central role of α-synuclein in the aggregation pathology, a distinct vulnerability of the striato-nigral system with the related motor symptoms, as well as specific mitochondrial deficits. Which molecular alterations cause neurodegeneration and drive PD pathogenesis is poorly understood. Here, we summarize evidence of the involvement of three interdependent factors in PD and suggest that their interplay is likely a trigger and/or aggravator of PD-related neurodegeneration: hypoxia, acidification and inflammation. We aim to integrate the existing knowledge on the well-established role of inflammation and immunity, the emerging interest in the contribution of hypoxic insults and the rather neglected effects of brain acidification in PD pathogenesis. Their tight association as an important aspect of the disease merits detailed investigation. Consequences of related injuries are discussed in the context of aging and the interaction of different brain cell types, in particular with regard to potential consequences on the vulnerability of dopaminergic neurons in the substantia nigra. A special focus is put on the identification of current knowledge gaps and we emphasize the importance of related insights from other research fields, such as cancer research and immunometabolism, for neurodegeneration research. The highlighted interplay of hypoxia, acidification and inflammation is likely also of relevance for other neurodegenerative diseases, despite disease-specific biochemical and metabolic alterations.


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