Renal cell carcinoma (RCC) is among the top ten most common forms of cancer and is the most common malignancy of the kidney. Clear cell renal carcinoma (cc-RCC), the most common type of RCC, is one ...of the most refractory cancers with an incidence that is on the rise. Screening of plant extracts in search of new anti-cancer agents resulted in the discovery of englerin A, a guaiane sesquiterpene with potent cytotoxicity against renal cancer cells and a small subset of other cancer cells. Though a few cellular targets have been identified for englerin A, it is still not clear what mechanisms account for the cytotoxicity of englerin A in RCC, which occurs at concentrations well below those used to engage the targets previously identified. Unlike any prior study, the current study used a systems biology approach to explore the mechanism(s) of action of englerin A. Metabolomics analyses indicated that englerin A profoundly altered lipid metabolism by 24 h in cc-RCC cell lines and generated significant levels of ceramides that were highly toxic to these cells. Microarray analyses determined that englerin A induced ER stress signaling and an acute inflammatory response, which was confirmed by quantitative PCR and Western Blot analyses. Additionally, fluorescence confocal microscopy revealed that englerin A at 25 nM disrupted the morphology of the ER confirming the deleterious effect of englerin A on the ER. Collectively, our findings suggest that cc-RCC is highly sensitive to disruptions in lipid metabolism and ER stress and that these vulnerabilities can be targeted for the treatment of cc-RCC and possibly other lipid storing cancers. Furthermore, our results suggest that ceramides may be a mediator of some of the actions of englerin A. Lastly, the acute inflammatory response induced by englerin A may mediate anti-tumor immunity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Gangliosides, the major sialic‐acid containing glycosphingolipids in the mammalian brain, play important roles in brain development and neural functions. Here, we show that the b‐series ganglioside ...GD3 and its biosynthetic enzyme, GD3‐synthase (GD3S), were up‐regulated predominantly in the microglia of mouse hippocampus from 2 to 7 days following global cerebral ischemia (GCI). Interestingly, GD3S knockout (GD3S‐KO) mice exhibited decreased hippocampal neuronal loss following GCI, as compared to wild‐type (WT) mice. While comparable levels of astrogliosis and microglial proliferation were observed between WT and GD3S‐KO mice, the phagocytic capacity of the GD3S‐KO microglia was significantly compromised after GCI. At 2 and 4 days following GCI, the GD3S‐KO microglia demonstrated decreased amoebic morphology, reduced neuronal material engulfment, and lower expression of the phagolysosome marker CD68, as compared to the WT microglia. Finally, by using a microglia‐primary neuron co‐culture model, we demonstrated that the GD3S‐KO microglia isolated from mouse brains at 2 days after GCI are less neurotoxic to co‐cultured hippocampal neurons than the WT‐GCI microglia. Moreover, the percentage of microglia with engulfed neuronal elements in the co‐cultured wells was also significantly decreased in the GD3S‐KO mice after GCI. Interestingly, the impaired phagocytic capacity of GD3S‐KO microglia could be partially restored by pre‐treatment with exogenous ganglioside GD3. Altogether, this study provides functional evidence that ganglioside GD3 regulates phagocytosis by microglia in an ischemic stroke model. Our data also suggest that the GD3‐linked microglial phagocytosis may contribute to the mechanism of delayed neuronal death following ischemic brain injury.
We found that ganglioside GD3 expression can be up‐regulated in microglia in the mouse brain after global cerebral ischemia. We also detected an increased neuronal survival, and decreased microglia phagocytosis in the hippocampal region of the GD3 synthase‐knockout (GD3S‐KO) mice compared to the WT after brain ischemia. We proposed that the up‐regulated GD3 enhanced the phagocytic capacity of microglia, which may contribute to the mechanism of delayed neuronal death following ischemic brain injury.
Adjuvant properties of bacterial cell wall components like MPLA (monophosphoryl lipid A) are well described and have gained FDA approval for use in vaccines such as Cervarix. MPLA is the product of ...chemically modified lipooligosaccharide (LOS), altered to diminish toxic proinflammatory effects while retaining adequate immunogenicity. Despite the virtually unlimited number of potential sources among bacterial strains, the number of useable compounds within this promising class of adjuvants are few. We have developed bacterial enzymatic combinatorial chemistry (BECC) as a method to generate rationally designed, functionally diverse lipid A. BECC removes endogenous or introduces exogenous lipid A-modifying enzymes to bacteria, effectively reprogramming the lipid A biosynthetic pathway. In this study, BECC is applied within an avirulent strain of
to develop structurally distinct LOS molecules that elicit differential Toll-like receptor 4 (TLR4) activation. Using reporter cell lines that measure NF-κB activation, BECC-derived molecules were screened for the ability to induce a lower proinflammatory response than
LOS. Their structures exhibit varied, dose-dependent, TLR4-driven NF-κB activation with both human and mouse TLR4 complexes. Additional cytokine secretion screening identified molecules that induce levels of tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8) comparable to the levels induced by phosphorylated hexa-acyl disaccharide (PHAD). The lead candidates demonstrated potent immunostimulation in mouse splenocytes, human primary blood mononuclear cells (PBMCs), and human monocyte-derived dendritic cells (DCs). This newly described system allows directed programming of lipid A synthesis and has the potential to generate a diverse array of TLR4 agonist candidates.
There is an urgent need to develop effective vaccines against infectious diseases that continue to be major causes of morbidity and mortality worldwide. Making effective vaccines requires selecting an adjuvant to strengthen an appropriate and protective immune response. This work describes a practical method, bacterial enzymatic combinatorial chemistry (BECC), for generating functionally diverse molecules for adjuvant use. These molecules were analyzed in cell culture for their ability to initiate immune stimulatory activity. Several of the assays described herein show promising
cytokine production and costimulatory molecule expression results, suggesting that the BECC molecules may be useful in future vaccine preparations.
The quantity and expression pattern of gangliosides in mammalian brain change drastically during development and are mainly regulated through stage‐specific expression of ganglioside synthase genes. ...Despite extensive investigations in the past, it remains largely unclear how the transcriptional activation of the genes encoding glycosyltransferases is regulated. Here, we show that in the neuronogenic cultures of mouse embryonic brain‐derived neuroepithelial cells, histone modifications including acetylated histone H3 and histone H4, but not histone H3 trimethylation at lysine 27 of two genes encoding two key regulatory GTs, namely, N‐acetylgalactosaminyltransferase I and sialyltransferase II, were extensively and gradually enhanced, respectively. As a consequence, the level of each GT mRNA was increased correspondingly. Hyperacetylation of histones on the GalNAcT promoter resulted in recruitment of the trans‐activation factors Sp2 and AP‐1 when cellular histone deacetylases 1 and 2 were knocked down with RNA interference or inhibited by treatment with valproic acid. Moreover, epigenetic activation of GalNAcT was also detected, as accompanied by a pronounced induction of neural differentiation in primary neuroepithelium culture responding to an exogenous supplement of ganglioside GM1, a downstream product of the gene's encoding enzyme. Our findings thus provide direct evidence of novel pathways for ganglioside expression via the epigenetic up‐regulation of ganglioside synthase genes during neural development.
Epigenetic regulation of two key regulatory glycosyltransferase (GT) genes, namely, GalNAcT and ST‐II, has been presented in NECs. GalNAcT was also activated, as accompanied by induction of neuronal differentiation, in mouse NECs responding to exogenously added GM1, a product of the gene's encoding enzyme. Thus, ganglioside expression can be regulated by the epigenetic regulation of GT genes during neural development.
Mucositis is a complex, dose-limiting toxicity of chemotherapy or radiotherapy that leads to painful mouth ulcers, difficulty eating or swallowing, gastrointestinal distress, and reduced quality of ...life for patients with cancer. Mucositis is most common for those undergoing high-dose chemotherapy and hematopoietic stem cell transplantation and for those being treated for malignancies of the head and neck. Treatment and management of mucositis remain challenging. It is expected that multiple genes are involved in the formation, severity, and persistence of mucositis. We used Ingenuity Pathway Analysis (IPA), a novel network-based approach that integrates complex intracellular and intercellular interactions involved in diseases, to systematically explore the molecular complexity of mucositis. As a first step, we searched the literature to identify genes that harbor or are close to the genetic variants significantly associated with mucositis. Our literature review identified 27 candidate genes, of which ERCC1, XRCC1, and MTHFR were the most frequently studied for mucositis. On the basis of this 27-gene list, we used IPA to generate gene networks for mucositis. The most biologically significant novel molecules identified through IPA analyses included TP53, CTNNB1, MYC, RB1, P38 MAPK, and EP300. Additionally, uracil degradation II (reductive) and thymine degradation pathways (p = 1.06-08) were most significant. Finally, utilizing 66 SNPs within the 8 most connected IPA-derived candidate molecules, we conducted a genetic association study for oral mucositis in the head and neck cancer patients who were treated using chemotherapy and/or radiation therapy (186 head and neck cancer patients with oral mucositis vs. 699 head and neck cancer patients without oral mucositis). The top ranked gene identified through this association analysis was RB1 (rs2227311, p-value = 0.034, odds ratio = 0.67). In conclusion, gene network analysis identified novel molecules and biological processes, including pathways related to inflammation and oxidative stress, that are relevant to mucositis development, thus providing the basis for future studies to improve the management and treatment of mucositis in patients with cancer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Gangliosides are sialylated glycosphingolipids (GSLs) with essential but enigmatic functions in brain activities and neural stem cell (NSC) maintenance. Our group has pioneered research on the ...importance of gangliosides for growth factor receptor signaling and epigenetic regulation of NSC activity and differentiation. The primary localization of gangliosides is on cell-surface microdomains and the drastic dose and composition changes during neural differentiation strongly suggest that they are not only important as biomarkers, but also are involved in modulating NSC fate determination. Ganglioside GD3 is the predominant species in NSCs and GD3-synthase knockout (GD3S-KO) revealed reduction of postnatal NSC pools with severe behavioral deficits. Exogenous administration of GD3 significantly restored the NSC pools and enhanced the stemness of NSCs with multipotency and self-renewal. Since morphological changes during neurogenesis require a huge amount of energy, mitochondrial functions are vital for neurogenesis. We discovered that a mitochondrial fission protein, the dynamin-related protein-1 (Drp1), as a novel GD3-binding protein, and GD3 regulates mitochondrial dynamics. Furthermore, we discovered that GM1 ganglioside promotes neuronal differentiation by an epigenetic regulatory mechanism. Nuclear GM1 binds with acetylated histones on the promoters of N-acetylgalactosaminyltransferase (GalNAcT; GM2 synthase) as well as on the NeuroD1 genes in differentiated neurons. In addition, epigenetic activation of the GalNAcT gene was detected as accompanied by an apparent induction of neuronal differentiation in NSCs responding to an exogenous supplement of GM1. GM1 is indeed localized in the nucleus where it can interact with transcriptionally active histones. Interestingly, GM1 could induce epigenetic activation of the tyrosine hydroxylase (TH) gene, with recruitment of nuclear receptor related 1 (Nurr1, also known as NR4A2), a dopaminergic neuron-associated transcription factor, to the TH promoter region. In this way, GM1 epigenetically regulates dopaminergic neuron specific gene expression. GM1 interacts with active chromatin via acetylated histones to recruit transcription factors at the nuclear periphery, resulting in changes in gene expression for neuronal differentiation. The significance is that multifunctional gangliosides modulate lipid microdomains to regulate functions of important molecules on multiple sites: the plasma membrane, mitochondrial membrane, and nuclear membrane. Versatile gangliosides could regulate functional neurons as well as sustain NSC functions via modulating protein and gene activities on ganglioside microdomains.
Adjuvants are central to the efficacy of subunit vaccines. Aluminum hydroxide (alum) is the most commonly used vaccine adjuvant, yet its adjuvanticity is often weak and mechanisms of triggering ...antibody responses remain poorly understood. We demonstrate that site-specific modification of immunogens with short peptides composed of repeating phosphoserine (pSer) residues enhances binding to alum and prolongs immunogen bioavailability. The pSer-modified immunogens formulated in alum elicited greatly increased germinal center, antibody, neutralizing antibody, memory and long-lived plasma cell responses compared to conventional alum-adsorbed immunogens. Mechanistically, pSer-immunogen:alum complexes form nanoparticles that traffic to lymph nodes and trigger B cell activation through multivalent and oriented antigen display. Direct uptake of antigen-decorated alum particles by B cells upregulated antigen processing and presentation pathways, further enhancing B cell activation. These data provide insights into mechanisms of action of alum and introduce a readily translatable approach to significantly improve humoral immunity to subunit vaccines using a clinical adjuvant.
The 2012 report of the President's Cancer Panel highlighted the overriding contribution of missed clinical opportunities to suboptimal HPV vaccination coverage. Since then, it remains unknown whether ...the rates of provider recommendations for the HPV vaccine in the US population have increased. We conducted an analysis of four rounds of the Health Information National Trends Survey (HINTS), a household survey of civilian US residents aged 18 y or older. A total of 1,415 (2012), 1,476 (2014), 1,208 (2017), and 1,344 (2018) respondents to the HINTS survey who were either HPV vaccine-eligible or living with HPV vaccine-eligible individuals were included. Overall, the rates of providers' recommendations remained stagnated from 2012 to 2018 in all categories of the study population, except for non-Hispanic Blacks (NHBs), where this prevalence increased during the study period (AAPC = 16.4%, p < .001). In vaccine-eligible individuals (18-27 y), declining trends were noted overall (AAPC = −21.6%, p < .001), among NHWs (AAPC = −30.2%, p < .001) and urban dwellers (AAPC = −21.4%, p < .001). Among vaccine-ineligible respondents (˃27 y) living with vaccine-eligible individuals, trends in the prevalence of provider recommendations for HPV vaccine were stagnating overall (AAPC = 0.5%, p = .90), and increasing only among NHBs (AAPC = 13.9%, p < .001). Despite recent progress, our findings indicate variations of trends in provider recommendations for the HPV vaccine in the US adult population according to age, sex, race/ethnicity, and residence. To accelerate HPV vaccination uptake, immediate actions to enhance provider recommendation for HPV vaccine are needed.
Amyloid β-peptides (Aβs) aggregate to form amyloid plaques, also known as senile plaques, which are a major pathological hallmark of Alzheimer’s disease (AD). Aβs are reported to possess ...proliferation effects on neural stem cells (NSCs); however, this effect remains controversial. Thus, clarification of their physiological function is an important topic. We have systematically evaluated the effects of several putative bioactive Aβs (Aβ1–40, Aβ1–42, and Aβ25–35) on NSC proliferation. Treatment of NSCs with Aβ1–42 significantly increased the number of those cells (149 ± 10 %). This was not observed with Aβ1–40 which did not have any effects on the proliferative property of NSC. Aβ25–35, on the other hand, exhibited inhibitory effects on cellular proliferation. Since cell surface glycoconjugates, such as glycolipids, glycoproteins, and proteoglycans, are known to be important for maintaining cell fate determination, including cellular proliferation, in NSCs and they undergo dramatic changes during differentiation, we examined the effect of Aβs on a number of key glycoconjugate metabolizing enzymes. Significantly, we found for the first time that Aβ1–42 altered the expression of several key glycosyltransferases and glycosidases, including fucosyltransferase IX (FUT9), sialyltransferase III (ST-III), glucosylceramide ceramidase (GLCC), and mitochondrial sialidase (Neu4). FUT9 is a key enzyme for the synthesis of the Lewis X carbohydrate epitope, which is known to be expressed in stem cells. Aβ1–42 also stimulated the Notch1 intracellular domain (NICD) by upregulation of the expression of Musashi-1 and the paired box protein, Pax6. Thus, Aβ1–42 upregulates NSC proliferation by modulating the expression of several glycogenes involved in Notch signaling.
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