Studying the effect of LPS on cytotoxicity and apoptosis in PC12 neuronal cells: Role of Bax, Bcl-2, and Caspase-3 protein expression

Renoprotective effect of hyperin against CdCl2 prompted renal damage by activation of Nrf-2/Keap-1 ARE pathway in male mice

OBJECTIVES

This study explored the mitigating properties of hyperin (HYP) on renotoxicity induced by cadmium chloride (CdCl2).

METHODS

Four groups of seven male albino mice each were used in this experiment. Group 1 served as the control, receiving no treatment. Group 2 received daily oral gavage of CdCl2 at 0.3 mg/kg body weight for 28 d. Group 3 received both CdCl2 (0.3 mg/kg) and HYP (100 mg/kg) daily using the same administration method. Finally, Group 4 received only HYP (100 mg/kg) daily.

RESULTS

Cd exposure significantly increased kidney dysfunction markers (blood urea nitrogen and creatinine) and oxidative stress (reactive oxygen species [ROS] and malondialdehyde [MDA]). Conversely, it decreased antioxidant enzyme activities (glutathione peroxidase (GPx] and catalase [CAT]) and glutathione (GSH) levels. Nuclear factor erythroid 2-related factor 2 (Nrf-2) and antioxidant gene expression decreased, while Kelch-like ECH-associated protein 1 expression increased. Additionally, Cd exposure increased inflammatory mediators (nuclear factor kappa B, tumor necrosis factor alpha [TNF-α], interleukin-1β [IL-1β], and cyclooxygenase-2) and apoptotic markers (Bax and caspase-3), alongside decreased Bcl-2 expression and renal tissue abnormalities. Mitochondrial dysfunction manifested with diminished activities of Krebs cycle and respiratory chain enzymes, and reduced mitochondrial membrane potential. Co-treatment with HYP significantly attenuated these detrimental effects through its anti-apoptotic, antioxidant, and anti-inflammatory properties.

CONCLUSION

HYP co-treatment significantly attenuated CdCl2-induced renal damage in mice, suggesting its potential as a protective agent against Cd-induced kidney toxicity.

Modulation of Apoptosis by Bovine Gammaherpesvirus 4 Infection in Bovine Endometrial Cells and the Possible Role of LPS in This Process

The prevalent pathogens associated with bovine uterine infections are bacteria that appear to increase the host's susceptibility to secondary infections with other bacteria or viruses, among which BoGHV4 is the most frequently found. In this work, the study of the pathways of apoptosis induction was carried out on an experimental model of primary culture of endometrial cells, in order to know the implication of BoGHV4 and the presence of bacterial LPS in the pathogenesis of the bovine reproductive tract. For this, different staining techniques and molecular analysis by RT-PCR were used. The results obtained allowed us to conclude that the level of cell death observed in the proposed primary culture is directly related to the time of viral infection and the presence of LPS in BoGHV4 infection. The apoptosis indices in cells infected with BoGHV4 and BoGHV4 + LPS revealed a maximum that correlated with the appearance of cytopathic effects and the maximum viral titers in the model studied. However, morphological, biochemical, and molecular changes were evident during both early and late stages of apoptosis. These findings provide information on the factors that may influence the pathogenesis of BoGHV4 and help to better understand the mechanisms involved in virus infection.

4R-cembranoid suppresses glial cells inflammatory phenotypes and prevents hippocampal neuronal loss in LPS-treated mice

Chronic neuroinflammation has been implicated in neurodegenerative disease pathogenesis. A key feature of neuroinflammation is neuronal loss and glial activation, including microglia and astrocytes. 4R-cembranoid (4R) is a natural compound that inhibits hippocampal pro-inflammatory cytokines and increases memory function in mice. We used the lipopolysaccharide (LPS) injection model to study the effect of 4R on neuronal density and microglia and astrocyte activation. C57BL/6J wild-type mice were injected with LPS (5 mg/kg) and 2 h later received either 4R (6 mg/kg) or vehicle. Mice were sacrificed after 72 h for analysis of brain pathology. Confocal images of brain sections immunostained for microglial, astrocyte, and neuronal markers were used to quantify cellular hippocampal phenotypes and neurons. Hippocampal lysates were used to measure the expression levels of neuronal nuclear protein (NeuN), inducible nitrous oxide synthase (iNOS), arginase-1, thrombospondin-1 (THBS1), glial cell-derived neurotrophic factor (GDNF), and orosomucoid-2 (ORM2) by western blot. iNOS and arginase-1 are widely used protein markers of pro- and anti-inflammatory microglia, respectively. GDNF promotes neuronal survival, and ORM2 and THBS1 are astrocytic proteins that regulate synaptic plasticity and inhibit microglial activation. 4R administration significantly reduced neuronal loss and the number of pro-inflammatory microglia 72 h after LPS injection. It also decreased the expression of the pro-inflammatory protein iNOS while increasing arginase-1 expression, supporting its anti-inflammatory role. The protein expression of THBS1, GDNF, and ORM2 was increased by 4R. Our data show that 4R preserves the integrity of hippocampal neurons against LPS-induced neuroinflammation in mice.

Iterative nanoparticle bioengineering enabled by x-ray fluorescence imaging

Nanoparticles (NPs) are currently developed for drug delivery and molecular imaging. However, they often get intercepted before reaching their target, leading to low targeting efficacy and signal-to-noise ratio. They tend to accumulate in organs like lungs, liver, kidneys, and spleen. The remedy is to iteratively engineer NP surface properties and administration strategies, presently a time-consuming process that includes organ dissection at different time points. To improve this, we propose a rapid iterative approach using whole-animal x-ray fluorescence (XRF) imaging to systematically evaluate NP distribution in vivo. We applied this method to molybdenum-based NPs and clodronate liposomes for tumor targeting with transient macrophage depletion, leading to reduced accumulations in lungs and liver and eventual tumor detection. XRF computed tomography (XFCT) provided 3D insight into NP distribution within the tumor. We validated the results using a multiscale imaging approach with dye-doped NPs and gene expression analysis for nanotoxicological profiling. XRF imaging holds potential for advancing therapeutics and diagnostics in preclinical pharmacokinetic studies.

Early-life galacto-oligosaccharides supplementation alleviates the small intestinal oxidative stress and dysfunction of lipopolysaccharide-challenged suckling piglets

BACKGROUND

Galacto-oligosaccharides (GOS) are non-digestible food ingredients that promote the growth of beneficial bacteria in the gut. This study investigated the protective effect of the early-life GOS supplement on the piglets' gut function against the oxidative stress induced by lipopolysaccharide (LPS)-challenge.

METHODS

Eighteen neonatal piglets were assigned to three groups including CON, LPS and LPS + GOS groups. The piglets in CON group and LPS group received physiological saline, while those in LPS + GOS group received GOS solution for 13 d after birth. On d 14, the piglets in LPS group and LPS + GOS group were injected with LPS solutions, while the piglets in CON group were injected with the same volume of physiological saline.

RESULTS

The results showed that the early-life GOS supplement blocked the LPS-induced reactive oxygen species (ROS) secretion, malondialdehyde (MDA) production and the increase of pro-apoptotic factor expression. Meanwhile, the early-life GOS supplement improved the activities of antioxidant enzymes, disaccharidase enzymes activities, and digestive enzymes activities, and increased the mRNA abundance of the gene related to nutrient digestion and absorption and the relative protein expression of tight junction. The study also showed that the early-life GOS supplement improved the expression of Hemeoxygenase-1 (HO-1) and NAD(P)H/quinone acceptor oxidoreductase-1 (NQO-1), and activated the AMP-activated protein kinase (AMPK).

CONCLUSIONS

These results suggested that GOS enhanced the gut function, reduced the ROS production and pro-apoptotic factors gene expression, and activated the AMPK signaling pathway in LPS-challenged piglets.

Yucca schidigera extract decreases nitrogen emission via improving nutrient utilisation and gut barrier function in weaned piglets

Yucca schidigera extract (YE) can decrease ammonia concentration in livestock housing, which could be associated with the inhibition of urease. The aim of this study was to investigate the other possible reasons of dietary YE supplementation reducing nitrogen emission in weaned piglets. A total of 14 crossbred weaned barrows were allotted into two groups fed the diets supplementing 0 and 120 mg/kg YE for 14 days. The YE administration decreased F/G ratio and hindgut NH₃ -N production in weaned piglets (p < 0.05). Dietary YE supplementation decreased serum urea nitrogen levels, and increased nutrient digestibility, which could be related to the improvement of morphology, digestive and absorptive enzyme activities, and nutrient transporter mRNA expression in jejunal mucosa of weaned piglets (p < 0.05). The mRNA expression of tight junction proteins, mucins and apoptosis-related genes was also improved by YE treatment in jejunal mucosa of weaned piglets (p < 0.05). In addition, dietary YE supplementation regulated the microbiota structure and volatile fatty acid content in distal intestine of weaned piglets (p < 0.05). These results suggest that YE administration can decrease hindgut NH₃ -N production in weaned piglets, which is associated with the increased nutrient utilization and gut-barrier function.

Conditioned Medium of Adipose-Derived Mesenchymal Stem Cells as a Promising Candidate to Protect High Glucose-Induced Injury in Cultured C28I2 Chondrocytes

Purpose: The aim of this study was to evaluate the protective effect of conditioned medium derived from human adipose mesenchymal stem cells (CM-hADSCs) on C28I2 chondrocytes against oxidative stress and mitochondrial apoptosis induced by high glucose (HG).

Methods: C28I2 cells were pre-treated with CM-hADSCs for 24 hours followed by HG exposure (75 mM) for 48 hours. MTT assay was used to assess the cell viability. Reactive oxygen species (ROS) and lipid peroxidation were determined by 2,7-dichlorofluorescein diacetate (DCFHDA) and thiobarbituric acid reactive substances (TBARS) assays, respectively. Expressions of glutathione peroxidase 3 (GPX 3), heme oxygenase-1 (HO-1), and NAD(P)H quinone dehydrogenase 1 (NQO1) were analyzed by RT-PCR. Finally, western blot analysis was used to measure Bax, Bcl-2, cleaved caspase-3, and Nrf-2 expression at protein levels.

Results: CM-hADSCs pretreatment mitigated the cytotoxic effect of HG on C28I2 viability. Treatment also markedly reduced the levels of ROS, lipid peroxidation, and augmented the expression of HO-1, NQO1, and GPx3 genes in HG-exposed group. CM-ADSCs enhanced Nrf-2 protein expression and reduced mitochondrial apoptosis through reducing Bax/Bcl-2 ratio and Caspase-3 activation.

Conclusion: MSCs, probably through its paracrine effects, declined the deleterious effect of HG on chondrocytes. Hence, therapies based on MSCs secretomes appear to be a promising therapeutic approaches to prevent joint complications in diabetic patients.

Hydrogen sulfide protects against IL-1β-induced inflammation and mitochondrial dysfunction-related apoptosis in chondrocytes and ameliorates osteoarthritis

The inflammatory environment and excessive chondrocyte apoptosis have been demonstrated to play crucial roles in the onset of osteoarthritis (OA). Hydrogen sulfide (H2 S), a gaseous signalling molecule, exerts an inhibitory effect on inflammation and apoptosis in several degenerative diseases. However, the protective effect of H2 S against OA has not been fully clarified, and its underlying mechanism should be examined further. In the current study, the role of endogenous H2 S in the pathogenesis of OA and its protective effects on interleukin (IL)-1β-induced chondrocytes were identified. Our data revealed decreased H2 S expression in both human degenerative OA cartilage tissue and IL-1β-induced chondrocytes. Pretreatment with the H2 S donor sodium hydrosulfide (NaHS) dramatically attenuated IL-1β-induced overproduction of inflammatory cytokines and improved the balance between anabolic and catabolic chondrocyte capacities, and these effects were dependent on PI3K/AKT pathway-mediated inhibition of nuclear factor kappa B (NF-κB). Moreover, mitochondrial dysfunction-related apoptosis was significantly reversed by NaHS in IL-1β-stimulated chondrocytes. Mechanistically, NaHS partially suppressed IL-1β-induced phosphorylation of the mitogen-activated protein kinase (MAPK) cascades. Furthermore, in the destabilization of the medial meniscus mouse model, OA progression was ameliorated by NaHS administration. Taken together, these results suggest that H2 S may antagonize IL-1β-induced inflammation and mitochondrial dysfunction-related apoptosis via selective suppression of the PI3K/Akt/NF-κB and MAPK signalling pathways, respectively, in chondrocytes and may be a potential therapeutic agent for the treatment of OA.

Bactericidal/Permeability-Increasing Protein Improves Cognitive Impairment in Diabetic Mice via Blockade of the LPS-LBP-TLR4 Signaling Pathway

Emerging evidence suggests that the bactericidal/permeability-increasing protein (BPI) is involved in the process of cognitive impairment in diabetes. However, its underlying mechanism remains elusive. In this study, we found that BPI affects cognitive impairment due to diabetes through the lipopolysaccharide (LPS)-lipopolysacharide-binding protein (LBP)-toll-like receptor 4 (TLR4) signaling pathway. We examined the expression of BPI, LPS, LBP, CD14, and TLR4 in established mouse models of diabetes induced by high-fat diet (HFD) in combination with streptozotocin (STZ). Diabetic mice were then injected with adeno-associated-virus carrying BPI overexpression vectors and LPS. Fasting blood glucose, plasma insulin, and serum levels of inflammatory factors were examined. Then, glucose tolerance and, insulin resistance tests were used to measure systemic insulin sensitivity. Next, hippocampal tissue injury and cell apoptosis were examined by hematoxylin-eosin (HE) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. Diabetic mice displayed increased LPS expression and activation of the LPS-CD14-TLR4 signaling pathway. HFD mice following LPS treatment showed significantly increased serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6, and expressions of Bcl-2-associated X protein (Bax) and Aβ but decreased expression of Bcl-2 in hippocampal tissues, as well as enhanced fasting blood glucose, plasma insulin, glucose tolerance, insulin tolerance, cell apoptosis, aggravated hippocampal tissue injury and, ultimately, cognitive impairment. However, overexpression of BPI was able to rescue the aforementioned phenotypes driven by LPS treatment. Taken together, BPI could potentially provide relief from cognitive impairment in diabetic mice by disrupting the LPS-LBP-TLR4 signaling pathway, underscoring a possible alternative therapeutic strategy against the cognitive impairment associated with diabetes.

Knockdown of SNHG1 alleviates autophagy and apoptosis by regulating miR-362-3p/Jak2/stat3 pathway in LPS-injured PC12 cells

Spinal cord injury (SCI) is a serious neurological disease. Long non-coding RNA (lncRNA) small nucleolar RNA host gene (SNHG1) and microRNA-362-3p (miR-362-3p) were confirmed to be related to neurological disorders. However, it is unclear whether SNHG1 was involved in the development of SCI via regulating miR-362-3p. PC12 cells were treated with lipopolysaccharide (LPS) to imitate the in vitro cell model of SCI. Cell ciability and apoptosis rate were detected by cell counting kit-8 (CCK-8) assay and flow cytometry assay. The levels of SNHG1, miR-362-3p, and Janus kinase-2 (Jak2) were examined by quantitative real-time polymerase chain reaction (qRT-PCR). The dual-luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation (RIP) assay were performed to verify the interaction between miR-362-3p and SNHG1 or Jak2. Besides, the levels of apoptosis- and autophagy- related proteins were detected by western blot assay. In present research, LPS suppressed cell viability, and induced apoptosis and autophagy in PC12 cells. SNHG1 knockdown could affect cell viability, and suppress cell apoptosis and autophagy in LPS-treated PC12 cells. Moreover, miR-362-3p was a target of SNHG1, miR-362-3p targeted Jak2 and negatively regulated Jak2/stat3 pathway. Our data also demonstrated that SNHG1 depletion inactivated Jak2/stat3 pathway to affect cell viability and confine apoptosis, autophagy in LPS-treated PC12 cells. Taken together, SNHG1 regulated cell viability, apoptosis and autophagy in LPS-treated PC12 cells by activating Jak2/stat3 pathway via sponging miR-362-3p.

Improvement of DC-based vaccines using adjuvant TLR4-binding 60S acidic ribosomal protein P2 and immune checkpoint inhibitors

Cancer immunotherapy has fewer side effects and higher efficiency than conventional methods. Dendritic cell (DC)-based vaccine, a cancer immunotherapeutic, is prepared by processing mature DCs and pulsing with tumor antigen peptide ex vivo, to induce the activation of tumor-specific T lymphocytes followed by tumor clearance in vivo. Unfortunately, clinical trials of this method mostly failed due to low patient response, possibly due to the absence of novel adjuvants that induce DC maturation through Toll-like receptor (TLR) signals. Interestingly, immune checkpoint inhibitor (ICI) therapy has shown remarkable anti-tumor efficacy when combined with cancer vaccines. In this study, we identified 60S acidic ribosomal protein P2 (RPLP2) through pull-down assay using human cancer cells derived proteins that binds to Toll-like receptor 4 (TLR4). Recombinant RPLP2 induced maturation and activation of DCs in vitro. This DC-based vaccine, followed by pulsing with tumor-specific antigen, has shown to significantly increase tumor-specific CD8⁺IFN-γ⁺ T cells, and improved both tumor prevention and tumor treatment effects in vivo. The adjuvant effects of RPLP2 were shown to be dependent on TLR4 using TLR4 knockout mice. Moreover, ICIs that suppress the tumor evasion mechanism showed synergistic effects on tumor treatment when combined with these vaccines.

LncRNA DANCR regulates the growth and metastasis of oral squamous cell carcinoma cells via altering miR-216a-5p expression

The study aims to investigate how DANCR can alter the growth and metastasis of oral squamous cell carcinoma (OSCC) cells by regulating miR-216a-5p. The expression of DANCR and miR-216a-5p in OSCC patients and cells were measured. SCC15 and CAL-27 cells were selected to divide into Control, sh-NC, DANCR shRNA, DANCR, miR-216a-5p mimic, and DANCR + miR-216a-5p mimic groups. Dual-luciferase reporter gene assay was performed for the verification of the targeting relationship between miR-216a-5p and DANCR/Bcl-2/KLF12. We also quantified the abilities of OSCC cells regarding proliferation, invasion, migration and apoptosis, and the expression levels of apoptosis-related proteins were measured. Finally, the tumor-bearing nude mice were established to verify the effect of DANCR in vivo. Up-regulated DANCR expression and down-regulated miR-216a-5p expression were observed in both OSCC tissues and cells, and they were proven strongly correlated to the histological grade, clinical staging and lymph node metastasis of OSCC patients. Dual-luciferase reporter gene assay showed a target relationship between DANCR and miR-216a-5p, as well as between miR-216a-5p and Bcl-2/KLF12. Both DANCR shRNA and miR-216a-5p mimic decreased proliferative, migration and invasive abilities of OSCC cells with increased cell apoptosis. However, DANCR group showed completely opposite trends. Moreover, miR-216a-5p mimic could reverse the role of DANCR in promoting tumor growth. In-vivo experiment confirmed the inhibitory role of DANCR shRNA in tumor growth and metastasis. We concluded that DANCR may promote the growth and metastasis of OSCC cells and suppress OSCC cell apoptosis by sponging miR-216a-5p.

Antibiotic-Antiapoptotic Dual Function of Clinacanthus nutans (Burm. f.) Lindau Leaf Extracts against Bovine Mastitis

Mastitis caused by bacterial infection has negative impacts on milk quality and animal health, and ultimately causes economic losses to the dairy industry worldwide. Gram-negative bacteria and their component lipopolysaccharide (LPS) can trigger the inflammatory response of endothelial cells (ECs) and subsequently promote EC dysfunction or injury, which is a critical pathogenesis of mastitis-causing sepsis shock. To control the bacterial infection and to minimise the LPS negative effects on ECs, we thus aimed to identify the potential herb extracts that comprised antibacterial activity and protective ability to inhibit LPS-induced cell death. Extracts from seven types of herbs derived from antibacterial screening were investigated for their protective effects on LPS-stimulated bovine endothelial cell line. Clinacanthus nutans (Burm. f.) Lindau (C. nutans) extract appeared to be the most effective antiapoptotic extract against LPS stimulation. Treatment of C. nutans extract in LPS-stimulated cells significantly lowered apoptotic cell death through modulating pro-survival Bcl-2 and pro-apoptotic Bax expression. The investigation of bioactive compounds using solvent fractionation, HPLC, and LC-MS/MS analysis revealed glyceryl 1,3-disterate (C₃₉H₇₆O₅), kaempferol 3-O-feruloyl-sophoroside 7-O-glucoside (C₄₃H₄₈O₂₄), and hydroxypthioceranic acid (C₄₆H₉₂O₃) as the candidate components. Our findings indicated that C. nutans extract has great potential to be further developed as an alternative therapeutic agent for mastitis treatment.

Effect of Novel Pyrrolo[3,4-d]pyridazinone Derivatives on Lipopolysaccharide-Induced Neuroinflammation

Neuroinflammation is considered to be one of the potential causes for the development of neurodegenerative diseases, including Alzheimer's disease. In this study, we evaluated the effect of four newly synthesized pyrrolo[3,4-d]pyridazinone derivatives on the neuron-like PC12 cells under simulated inflammation conditions by preincubation with lipopolysaccharide (LPS). Our novel derivatives are selective cyclooxygenase-2 (COX-2) inhibitors and have similar effects to nonsteroidal anti-inflammatory drugs (NSAIDs). We assessed viability (LDH assay), metabolic activity (MTT assay), DNA damage (number of double-strand breaks measured by fast halo assay), and the neuronal features of cells (average neurite length and neurite outgrowth measured spectrofluorimetrically). DCF-DA and Griess assays were also performed, which allowed determining the impact of the tested compounds on the level of oxygen free radicals and nitrites. LPS administration significantly negatively affected the results in all tests performed, and treatment with the tested derivatives in most cases significantly reduced this negative impact. Multiple-criteria decision analysis indicated that overall, the best results were observed for compounds 2a and 2b at a concentration of 10 µM. The new derivatives showed intense activity against free oxygen radicals and nitrites. Reduced reactive oxygen species level also correlated with a decrease in the number of DNA damage. The compounds improved neuronal features, such as neurite length and outgrowth, and they also increased cell viability and mitochondrial activity. Our results suggest that derivatives 2a and 2b may also act additionally on mechanisms other than 3a and 3b.

Magnetite-OmpA Nanobioconjugates as Cell-Penetrating Vehicles with Endosomal Escape Abilities

Outer membrane protein A (OmpA) has been extensively studied in Gram-negative bacteria due to its relevance in the adhesion of pathogens to host cells and its surfactant capabilities. It consists of a hydrophobic β-barrel domain and a hydrophilic periplasmic domain, that confers OmpA an amphiphilic structure. This study aims to elucidate the capacity of Escherichia coli OmpA to translocate liposomal membranes and serve as a potential cell-penetrating vehicle. We immobilized OmpA on magnetite nanoparticles and investigated the possible functional changes exhibited by OmpA after immobilization. Liposomal intake was addressed using egg lecithin liposomes as a model, where magnetite-OmpA nanobioconjugates were able to translocate the liposomal membrane and caused a disruptive effect when subjected to a magnetic field. Nanobioconjugates showed both low cytotoxicity and hemolytic tendency. Additional interactions within the intracellular space led to altered viability results via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Confocal microscopy images revealed that immobilized nanoparticles effectively enter the cytoplasm of THP-1 and Vero cells by different routes, and, subsequently, some escape endosomes, lysosomes, and other intracellular compartments with relatively high efficiencies. This was demonstrated by co-localization analyses with LysoTracker green that showed Pearson correlations of about 80 and 28%.

Mitochondrial signaling in inflammation-induced depressive behavior in female and male rats: The role of glucocorticoid receptor

Mitochondrial dysfunction can result from the interplay between elevated inflammatory markers and alterations in hypothalamic-pituitary-adrenal (HPA) axis, and can contribute to pathogenesis of major depression. Therefore, in this study we investigated whether the effects of lipopolysaccharide (LPS) on glucocorticoid receptor (GR) could be associated with alterations in mitochondrial apoptotic signaling in the prefrontal cortex of male and female Wistar rats with depressive-like behavior. To that end, we measured LPS-induced alterations in the extrinsic and intrinsic apoptotic pathways in mitochondria and cytosol of PFC of female and male rats, as well as the levels of cleaved cytosolic PARP-1. We also measured the mitochondrial levels of GR and its phosphoisoforms pGR232 and pGR246, as well as the mRNA levels of two GR-regulated mitochondrial genes, COX-1 and COX-3. We discovered that although seven-day LPS treatment evoked depressive-like behavior and induced apoptosis in the PFC of both sexes, it affected apoptotic cascades in both sexes differently. In females the treatment initiated both intrinsic and extrinsic apoptotic cascade, while in males only intrinsic cascade was engaged. Alterations in intrinsic apoptotic pathway were more associated with GR alterations in males, where LPS treatment decreased levels of mitochondrial GR and increased pGR232/pGR246 ratio. Alterations in mitochondrial GR could be associated with changes in expression of genes involved in oxidative metabolism in the PFC of this sex, and could, in combination with elevated levels of BCL-2 and decreased levels of BAX detected in this cell fraction, mitigate the detrimental effect of LPS on mitochondria in male PFC.

Gynura bicolor aqueous extract attenuated H2O2 induced injury in PC12 cells

BACKGROUND

Protective effects of Gynura bicolor aqueous extract (GAE) at three concentrations upon nerve growth factor (NGF) differentiated-PC12 cells against H₂O₂ induced injury were examined.

METHODS

NGF differentiated-PC12 cells were treated with GAE at 0.25%, 0.5% or 1%. 100 μM H₂O₂ was used to treat cells with GAE pre-treatments. After incubating at 37 °C for 12 hr, experimental analyses were processed.

RESULTS

H₂O₂ exposure decreased cell viability, increased plasma membrane damage, suppressed Bcl-2 mRNA expression and enhanced Bax mRNA expression. GAE pre-treatments reversed these changes. H₂O₂ exposure reduced mitochondrial membrane potential, lowered Na⁺-K⁺-ATPase activity, and increased DNA fragmentation and Ca²⁺ release. GAE pre-treatments attenuated these alterations. H₂O₂ stimulated the production of reactive oxygen species (ROS), interleukin (IL)-1beta, IL-6 and tumor necrosis factor-alpha, lowered glutathione content, and reduced glutathione peroxidase (GPX) and catalase activities. GAE pretreatments maintained GPX and catalase activities; and concentration-dependently diminished the generation of ROS and inflammatory cytokines. H₂O₂ enhanced mRNA expression of nuclear factor kappa (NF-κ) B and p38. GAE pre-treatments decreased mRNA expression of NF-κB and p38.

CONCLUSION

These findings suggested that GAE might be a potent neuronal protective agent.

BAX Gene Overexpression in the Tongue Could Warn of Infection Risk due to Periodontal Pathogens

Background:

Different host proteins play a central role in cell response during bacterial infections, the Bcl-2-Associated X protein (BAX) and Vascular Cell Adhesion Protein 1 (VCAM-1) are often reported in infective primary events during cell injury.

Objective:

The aim of this study is to evaluate the predictive value of these two proteins as biomarkers of oral bacterial infection, with particular emphasis on the tongue, which plays an important role in microbial homeostasis in the mouth.

Methods:

Twenty-nine patients were recruited and divided according to the Periodontal Index (CPI), 4 of them were severely compromised periodontal patients. Oral hygiene, gingival tissues and plaque presence were evaluated clinically. The laboratory analysis carried out on tongue tissue included: total bacterial genomes, proportion of specific periopathogens and BAX -VCAM-1 expression rate, while Reactive Oxygen Species (ROS) were measured in saliva.

Results:

Neither tongue microbiological status nor salivary ROS level corresponded with the state of disease. VCAM-1 mRNA expression rate was comparable in all patients but, on the contrary, BAX expression resulted high in periodontally-compromised patients and appears related to periodontal status in the analyzed subjects.

Conclusion:

This preliminary work suggests that the BAX protein is a possible candidate in a prognostic marker study for oral diseases started by periodontal bacteria. For example, none of the evaluated clinical and microbiological parameters could predict the presence, prognosis or recurrence of periodontal diseases. This biomarker could be a valuable tool in determining the risk, diagnosis and prognosis of this human illness.

Hypoxia-mediated mitochondria apoptosis inhibition induces temozolomide treatment resistance through miR-26a/Bad/Bax axis

Glioblastoma multiforme (GBM) is one of the most hypoxic tumors of the central nervous system. Although temozolomide (TMZ) is an effective clinical agent in the GBM therapy, the hypoxic microenvironment remains a major barrier in glioma chemotherapy resistance, and the underlying mechanisms are poorly understood. Here, we find hypoxia can induce the protective response to mitochondrion via HIF-1α-mediated miR-26a upregulation which is associated with TMZ resistance in vitro and in vivo. Further, we demonstrated that HIF-1α/miR-26a axis strengthened the acquisition of TMZ resistance through prevention of Bax and Bad in mitochondria dysfunction in GBM. In addition, miR-26a expression levels negatively correlate with Bax, Bad levels, and GBM progression; but highly correlate with HIF-1α levels in clinical cancer tissues. These findings provide a new link in the mechanistic understanding of TMZ resistance under glioma hypoxia microenvironment, and consequently HIF-1α/miR-26a/Bax/Bad signaling pathway as a promising adjuvant therapy for GBM with TMZ.

Rosiglitazone Reduces Apoptosis and Inflammation in Lipopolysaccharide-Induced Human Umbilical Vein Endothelial Cells

BACKGROUND Although the peroxisome proliferator-activated receptor-g (PPARg) agonist rosiglitazone has significant anti-inflammatory properties, no scientific studies have provided new insights in its pharmacological properties with respect to acute respiratory distress syndrome (ARDS). The present investigation aimed to evaluate whether rosiglitazone can reduce apoptosis and inflammation in a lipopolysaccharide (LPS)-induced acute respiratory distress syndrome in vitro model. MATERIAL AND METHODS Human umbilical vein endothelial cells (HUVECs) were treated with 1 µg/ml LPS in the absence or presence of 10 µM rosiglitazone for 24 h. Cell viability was measured by MTT assay. Flow cytometry was used to examine the cell apoptosis and ROS production in HUVECs response to LPS and rosiglitazone. The levels of pro-inflammatory cytokine factors, including TNF-α, IL-6, CXCL12, and CXCR4, were measured by ELISA, real-time PCR, and Western blot assay, respectively. The expression of PPARg, Bcl-2, and Bax and the activity of JAK2 and STAT3 were also investigated by Western blot assay. RESULTS We found that rosiglitazone significantly inhibited LPS-induced cell apoptosis, ROS production, and inflammation in HUVECs. Furthermore, we found a significant reduction of JAK2/STAT3 activation and the Bax/Bcl-2 ratio in LPS-induced HUVECs response to rosiglitazone treatment. CONCLUSIONS Treatment with rosiglitazone can reduce apoptosis and inflammation in HUVECs induced by LPS.

Metabolic Enhancer Piracetam Attenuates the Translocation of Mitochondrion-Specific Proteins of Caspase-Independent Pathway, Poly [ADP-Ribose] Polymerase 1 Up-regulation and Oxidative DNA Fragmentation

Piracetam, a nootropic drug, has been clinically used for decades; however, its mechanism of action still remains enigmatic. The present study was undertaken to evaluate the role of mitochondrion-specific factors of caspase-independent pathway like apoptotic-inducing factor (AIF) and endonuclease-G (endo-G) in piracetam-induced neuroprotection. N2A cells treated with lipopolysaccharide (LPS) exhibited significant cytotoxicity, impaired mitochondrial activity, and reactive oxygen species generation which was significantly attenuated with piracetam co-treatment. Cells co-treated with LPS and piracetam exhibited significant uptake of piracetam in comparison to only piracetam-treated cells as estimated by liquid chromatography-mass spectrometry (LC-MSMS). LPS treatment caused significant translocation of AIF and endonuclease-G in neuronal N2A cells which were significantly attenuated with piracetam co-treatment. Significant over-expression of proinflammatory cytokines was also observed after treatment of LPS to cells which was inhibited with piracetam co-treatment demonstrating its anti-inflammatory property. LPS-treated cells exhibited significant oxidative DNA fragmentation and poly [ADP-ribose] polymerase-1 (PARP-1) up-regulation in nucleus, both of which were attenuated with piracetam treatment. Antioxidant melatonin but not z-VAD offered the inhibited LPS-induced DNA fragmentation indicating the involvement of oxidative DNA fragmentation. Further, we did not observe the altered caspase-3 level after LPS treatment initially while at a later time point, significantly augmented level of caspase-3 was observed which was not inhibited with piracetam treatment. In total, our findings indicate the interference of piracetam in mitochondrion-mediated caspase-independent pathway, as well as its anti-inflammatory and antioxidative properties. Graphical Abstract Graphical abstract indicating the novel interference of metabolic enhancer piracetam (P) in neuronal death mechanisms.

High C-X-C motif chemokine 5 expression is associated with malignant phenotypes of prostate cancer cells via autocrine and paracrine pathways

The present study aimed to examine the effects and mechanisms of exogenous C-X-C motif chemokine 5 (CXCL5) and lentiviral CXCL5 overexpression on the regulation of malignant behaviors of prostate cancer cells in vitro and in a nude mouse xenograft model. The expression levels of CXCL5 and a number of tumor-related genes were assessed by using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), western blotting, ELISA, or immunohistochemistry in normal and cancerous prostate cells and tissues. Cell proliferation, colony formation, and Transwell assays were performed to determine the effects of exogenous, autocrine, and paracrine CXCL5 on prostate cancer cell proliferative and migratory capacity. The results indicated that CXCL5 expression was upregulated in PC‑3 and DU145 prostate cancer cells, in WPMY‑1 normal prostate stromal cells, and in RWPE‑1 prostate epithelial cells, as well as in prostate cancer tissue specimens. Exogenous CXCL5 exposure resulted in increase in prostate cancer cell proliferation, colony formation, and migration. In cells transfected with a CXCL5 overexpression vector, in cells cultured in conditioned medium from CXCL5-overexpressing WPMY cells, and in cells co-cultured with CXCL5‑OE WPMY cells prostate cancer cell malignant phenotypes were induced in an autocrine/paracrine fashion in vitro; similar results were observed in nude mouse xenografts. CXCL5 overexpression also regulated expression of tumor-related genes, including BAX, N-Myc downstream-regulated gene 3, extracellular signal-regulated kinase 1/2, C-X-C chemokine receptor type 2, interleukin 18, Bcl‑2, and caspase‑3. These data demonstrated that CXCL5 expression was upregulated in prostate cancer tissues and that exogenous CXCL5 protein exposure or CXCL5 overexpression promoted malignant phenotypes of prostate cancer cells in vitro and in vivo.

The effects of hydrogen peroxide and lipopolysaccharide on rat alveolar L2 cells

PURPOSE

This study aimed to investigate differential cell responses of alveolar epithelial cells (AECs) after treatments with lipopolysaccharide (LPS) and hydrogen peroxide (H₂O₂) to mimic the exposure to inflammation and oxidative stress and the mechanisms of a double-hit model of apoptosis.

MATERIALS AND METHODS

AECs were cultured and treated with combinations of 1 μg/mL of LPS and 500 μM H₂O₂ as follows: LPS-only at 0 h, LPS at 0 h with H₂O₂ at 6 h (LPS + H₂O₂), H₂O₂-only at 0 h, H₂O₂ at 0 h with LPS at 6 h (H₂O₂ + LPS), and control. We investigated mRNA expression (TNF-α, Fas, Fas ligand, Bax, Bcl-2, Caspase-7), protein expression (Fas, Bax, Bcl-2, Caspase-7) and apoptosis (Caspase-3 activity, TUNEL assay) at 0, 3, 6, 9, 12, and 24 h.

RESULTS

In the H₂O₂ + LPS group, the Caspase-7, and Fas mRNA levels were significantly higher than the other groups at 9 h and 12 h, and Bax was higher at 12 h. The Bax/Bcl-2 protein expression ratio was significantly higher in the H₂O₂ + LPS group than that of the other groups at 12h and 24h. Apoptotic index was highest in the H₂O₂ + LPS group at 24 h.

CONCLUSIONS

The sequence of stimulation may modify the cell response in rat AECs. The results suggest that previous oxidative stress and subsequent LPS-induced inflammation primarily influence apoptosis of L2 cells by up-regulation of cell signaling.

Dyrk2 involved in regulating LPS-induced neuronal apoptosis

The activation of relevant signaling pathways plays a very important role in LPS-induced neuronal damage. Dual-specificity tyrosine-phosphorylation-regulated kinase 2(Dyrk2), as a phosphokinase that can directly or indirectly phosphorylate signal molecules, was recently reported to down-regulate Type I Interferon(TIF) by promoting ser527 phosphorylation of TBK1. To further investigate the role of Dyrk2 in neuroinflammation, we for the first time focused on its function in LPS-induced neuronal damage. We found LPS stimulation increased the expression of Dyrk2 in the nucleus and cytoplasm of neurons. In addition, overexpression of Dyrk2 not only reduced the level of TNF-α induction, but also obviously inhibited LPS-induced neuronal apoptosis. We further found that Dyrk2 promoted the induction of phospho-Akt, phospho-p65 and phospho-p38MAPK (p38 mitogen-activated protein kinase), but immunoprecipitation showed Dyrk2 interacted with and Akt, p38MAPK and IκBα (IkappaB-alpha), except NF-κB subunit p65. These findings suggest Dyrk2 can inhibit LPS-induced neuronal apoptosis and plays key roles in LPS-indcued signaling pathways by its phosphokinase function. These data provide a novel viewpoint that Dyrks family may have an important role in neuroinflammation, and provide a potential molecular target for improving neuronal apoptosis.

Lacritin Salvages Human Corneal Epithelial Cells from Lipopolysaccharide Induced Cell Death

Innate immunity of the corneal epithelium is conferred by proteinaceous secretions from the epithelium and associated lacrimal and meibomian glands. Lacritin, an eye-specific protein with anti-microbial, cytoprotective and wound-healing properties, predominantly secreted by lacrimal glands, is absent in conditions such as Dry eye and Keratitis. In view of the biological significance of lacritin in human eye, we investigated its role in human corneal epithelial (HCE) cells during lipopolysaccharide (LPS)-induced infection. LPS-challenged HCE cells demonstrated apoptosis-mediated cell death and elevated lacritin levels. The LPS-induced cell death is alleviated with exogenous supplementation of recombinant lacritin. This cytoprotective effect of lacritin is mediated through Cyclooxygenase-2 (COX-2). This study is the first to highlight the protective role of lacritin and mechanism of its action during bacterial infection of cornea in vitro.

Attenuation of cellular toxicity by calpain inhibitor induced by bacterial endotoxin: a mechanistic study using muscle precursor cells as a model system

This investigation was under taken to explore probable mechanisms and signal pathways involved in cytotoxicity induced by bacterial endotoxin lipopolysaccharide (LPS). Herein, we selected muscle precursor C2C12 myoblasts as representative cells to test effect of calpain inhibitor 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606) on LPS induced inflammation and apoptosis. In order to rule out the toxicity of endotoxin, mouse myoblasts were exposed to various concentrations of LPS and viability of cells and morphology were assessed using CCK-8 assay and simple microscopy respectively. Apoptotic cell death was examined by fluorescence microscope at regular time intervals. Additionally, LPS induced apoptosis in C2C12 cells were determined by mRNA expression of µ-calpain, caspase-3 and tumor necrosis factor alpha (TNF-α) and were quantified by qRT-PCR. Our results point out that LPS stimulation produced dose dependent toxicity in muscle precursor cells. Pre-treatment with a calpain inhibitor can significantly attenuate LPS-induced inflammation/apoptosis. Results of present research determined that mRNA expression of aforesaid genes was amplified (p<0.05) in LPS stimulated C2C12 cells, whereas a noticeable drop off in mRNA expression of these genes was observed when pre-exposed with calpain inhibitor PD150606. Our study has outlined the current understanding regarding the connection between µ-calpain and caspase-3 in skeletal muscle wasting and as a result provides suitable choice for designing promising chemotherapeutic system for muscle illness and atrophy.

GM1 and GD1a gangliosides modulate toxic and inflammatory effects of E. coli lipopolysaccharide by preventing TLR4 translocation into lipid rafts

Exogenous gangliosides are known to inhibit the effects of Escherichia coli lipopolysaccharide (LPS) in different cells exhibiting anti-inflammatory and immunosuppressive activities. The mechanisms underlying ganglioside action are not fully understood. Because LPS recognition and receptor complex formation occur in lipid rafts, and gangliosides play a key role in their maintenance, we hypothesize that protective effects of exogenous gangliosides would depend on inhibition of LPS signaling via prevention of TLR4 translocation into lipid rafts. The effect of GM1 and GD1a gangliosides on LPS-induced toxic and inflammatory reactions in PC12 cells, and in epithelial cells isolated from the frog urinary bladder, was studied. In PC12 cells, GD1a and GM1 significantly reduced the effect of LPS on the decrease of cell survival and on stimulation of reactive oxygen species production. In epithelial cells, gangliosides decreased LPS-stimulated iNOS expression, NO, and PGE2 production. Subcellular fractionation, in combination with immunoblotting, showed that pretreatment of cells with GM1, GD1a, or methyl-β-cyclodextrin, completely eliminated the effect of LPS on translocation of TLR4 into lipid rafts. The results are consistent with the hypothesis that ganglioside-induced prevention of TLR4 translocation into lipid rafts could be a mechanism of protection against LPS in various cells.

Alterations in Caenorhabditis elegans and Cronobacter sakazakii lipopolysaccharide during interaction

Lipopolysaccharide is one of the pathogen-associated molecular patterns of Gram-negative bacteria which are essential for its pathogenicity. Cronobacter sakazakii is an opportunistic, emergent pathogen, which infects and cause mortality in Caenorhabditis elegans. In this study, modifications in host and C. sakazakii LPS during infections were evaluated. The physiological assays revealed that LPS alone is sufficient to affect the host pharyngeal pumping rate, brood size and cause lethality. FTIR spectra of LPS revealed that C. sakazakii modifies its LPS to escape from the recognition of host immune system. These results indicate that LPS plays a key role in C. sakazakii pathogenicity. qPCR studies revealed that LPS modulated the expression of selected host immune (clec-60, clec-87, lys-7, ilys-3, F08G5.6, atf-7, scl-2, cpr-2) and aging-related genes (skn-1, clk-2, bra-2, age-1, bec-1, daf-16, daf-2). Moreover, it was confirmed that p38 MAPK pathway has a major role in host immune response against LPS-mediated challenges.

Burn injury induces gelsolin expression and cleavage in the brain of mice

Gelsolin is an actin filament-severing and capping protein, affecting cellular motility, adhesiveness and apoptosis. Whether it is expressed in the brain of burned mice has not yet been characterized. Mice were subjected to a 15% total body surface area scald injury. Neuropathology was examined by hematoxylin and eosin staining. Cerebral gelsolin mRNA, distribution and cleavage were demonstrated by quantitative polymerase chain reaction (QPCR), immunohistochemistry and Western blot, respectively. Cysteinyl aspartate-specific protease (caspase)-3-positive cells and activity were also measured. Burn injury could induce pathological alterations in the brain including leukocyte infiltration, necrosis, microabscess and gliosis. Compared with sham-injured mice, gelsolin mRNA was up-regulated at 8h post-burn (pb) in a transient manner in the cortex and striatum of burned mice, while it remained at higher levels in the hippocampus up to 72 hpb. Of interest, gelsolin was further cleaved into 42 and 48 kDa (kilo Dalton) fragments as illustrated in the hippocampus at 24 hpb, and was widely expressed in the brain by activated monocyte/macrophages, astrocytes and damaged neurons. In the meantime, caspase-3-positive cells were noted in the striatum of burned mice and its activity peaked at 24 hpb. To clarify inflammation-induced gelsolin expression and cleavage in the brain, rat pheochromocytoma cells were exposed to lipopolysaccharide to show increased gelsolin expression and caspase-3-dependent cleavage. The results suggest that burn-induced cerebral gelsolin expression would be involved in the activation of both the monocytes and astroglial cells, thereby playing a crucial role in the subsequent inflammation-induced neural apoptosis following burn injury.

Mechanistic explanations how cell-mediated immune activation, inflammation and oxidative and nitrosative stress pathways and their sequels and concomitants play a role in the pathophysiology of unipolar depression

This paper reviews that cell-mediated-immune (CMI) activation and inflammation contribute to depressive symptoms, including anhedonia; anxiety-like behaviors; fatigue and somatic symptoms, e.g. illness behavior or malaise; and mild cognitive impairment (MCI). These effects are in part mediated by increased levels of pro-inflammatory cytokines (PICs), e.g. interleukin-1 (IL-1), IL-6 and tumor necrosis factor (TNF)α, and Th-1-derived cytokines, such as IL-2 and interferon (IFN)γ. Moreover, new pathways, i.e. concomitants and sequels of CMI activation and inflammation, were detected in depression: (1) Induction of indoleamine 2,3-dioxygenase (IDO) by IFNγ and some PICs is associated with depleted plasma tryptophan, which may interfere with brain 5-HT synthesis, and increased production of anxiogenic and depressogenic tryptophan catabolites. (2) Increased bacterial translocation may cause depression-like behaviors by activating the cytokine network, oxidative and nitrosative stress (O&NS) pathways and IDO. (3) Induction of O&NS causes damage to membrane ω3 PUFAs, functional proteins, DNA and mitochondria, and autoimmune responses directed against intracellular molecules that may cause dysfunctions in intracellular signaling. (4) Decreased levels of ω3 PUFAs and antioxidants, such as coenzyme Q10, glutathione peroxidase or zinc, are associated with an increased inflammatory potential; more oxidative damage; the onset of specific symptoms; and changes in the expression or functions of brain 5-HT and N-methyl-d-aspartate receptors. (5) All abovementioned factors cause neuroprogression, that is a combination of neurodegeneration, neuronal apoptosis, and lowered neurogenesis and neuroplasticity. It is concluded that depression may be the consequence of a complex interplay between CMI activation and inflammation and their sequels/concomitants which all together cause neuroprogression that further shapes the depression phenotype. Future research should employ high throughput technologies to collect genetic and gene expression and protein data from patients with depression and analyze these data by means of systems biology methods to define the dynamic interactions between the different cell signaling networks and O&NS pathways that cause depression.

Regulation of Caenorhabditis elegans and Pseudomonas aeruginosa machinery during interactions

The amenability of Caenorhabditis elegans against pathogen provides a valuable tool for studying host-pathogen interactions. Physiological experiments revealed that the P. aeruginosa was able to kill C. elegans efficiently. The effects of P. aeruginosa PA14, PAO1 and their isolated lipopolysaccharide (LPS) on the host system were analyzed. The LPS at higher concentrations (≥2 mg/ml) was toxic to the host animals. Kinetic studies using qPCR revealed the regulation of host-specific candidate antimicrobial genes during pathogen-mediated infections. In addition, the pathogen-specific virulent gene, exoT expression, was anlyzed and found to be varied during the interactions with the host system. Ability of the pathogens to modify their internal machinery in the presence of the host was analyzed by XRD, FTIR and PCA. LPS isolated from pathogens upon exposure to C. elegans showed modifications at their functional regions. LPS from PAO1 showed difference in d-spacing angle (Å) and °2Th position. FTIR spectra revealed alterations in polysaccharide (1,200-900 cm(-1)) and fatty acid (3,000-2,800 cm(-1)) regions of LPS from P. aeruginosa PAO1 exposed to the host system. These data provide additional insights on how the pathogens subvert its own and host machinery during interactions.

Protective effect of diosmin on LPS-induced apoptosis in PC12 cells and inhibition of TNF-α expression

Several studies have demonstrated a link between increased pro-inflammatory mediators and apoptosis in neurodegenerative diseases. It has been reported that lipopolysaccharide (LPS) induces apoptosis mostly through the production of TNF-α. In this study, we investigated the possible protective and anti-inflammatory mechanisms of diosmin, a natural flavone glycoside, on LPS-induced PC12 cells death through inhibition of TNF-α production. PC12 Cells were pretreated with diosmin for 2h prior to LPS treatment for 48 h to assess PC12 cells viability, TNF-α expression, and cell death mechanisms. Diosmin significantly increased cells survival and suppressed LPS-induced TNF-α in a concentration-dependent manner. Diosmin also significantly reduced the DNA fragmentation of LPS-induced cells, and its anti-apoptotic effect was confirmed by the decrease in the expression of pro-apoptotic protein Bad and the increase in the expression of anti-apoptotic protein Bcl-2 on Western blot analysis. Furthermore, diosmin inhibited LPS-induced caspase-3 activation further confirming its anti-apoptotic effects. This is the first study to report the anti-inflammatory and anti-apoptotic effects of diosmin via inhibition of TNF-α and a caspase-dependent pathway in neuronal PC12 cells. These results support the potential for diosmin to be investigated as a potential agent for the treatment of neurodegenerative diseases.