Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish

<p>Abstract</p> <p>Background</p> <p>Although unsaturated fatty acids such as eicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (ARA, C20:4n-6), collectively known as the highly unsaturated fatty acids (HUFA), play pivotal roles in vertebrate reproduction, very little is known about their synthesis in the ovary. The zebrafish (Danio rerio) display capability to synthesize all three HUFA via pathways involving desaturation and elongation of two precursors, the linoleic acid (LA, C18:2n-6) and linolenic acid (LNA, C18:3n-3). As a prerequisite to gain full understanding on the importance and regulation of ovarian HUFA synthesis, we described here the mRNA expression pattern of two enzymes; desaturase (fadsd6) and elongase (elovl5), involved in HUFA biosynthesis pathway, in different zebrafish ovarian follicle stages. Concurrently, the fatty acid profile of each follicle stage was also analyzed.</p> <p>Methods</p> <p>mRNA levels of fadsd6 and elovl5 in different ovarian follicle stages were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assays. For analysis of the ovarian follicular fatty acid composition, gas chromatography was used.</p> <p>Results</p> <p>Our results have shown that desaturase displayed significant upregulation in expression during the oocyte maturation stage. Expression of elongase was significantly highest in pre-vitellogenic follicles, followed by maturation stage. Fatty acid composition analysis of different ovarian follicle stages also showed that ARA level was significantly highest in pre-vitellogenic and matured follicles. DHA level was highest in both late vitellogenic and maturation stage.</p> <p>Conclusion</p> <p>Collectively, our findings seem to suggest the existence of a HUFA synthesis system, which could be responsible for the synthesis of HUFA to promote oocyte maturation and possibly ovulation processes. The many advantages of zebrafish as model system to understand folliculogenesis will be useful platform to further elucidate the regulatory and mechanism aspects of ovarian HUFA synthesis.</p

Paclitaxel Inhibits Expression of Neuronal Nitric Oxide Synthase and Prevents Mitochondrial Dysfunction in Spinal Ventral Horn in Rats After C7 Spinal Root Avulsion

AIm: This study evaluated the neuroprotective effect of intrathecally infused paclitaxel in the prevention of motoneuron death and mitochondrial dysfunction following brachial plexus avulsion injury. Mat erIal and Methods: Brachial root avulsion injury was induced in Sprague-Dawley rats. The Paclitaxel treatment group (n = 32) received a 5-d intrathecal infusion of paclitaxel (256 ng/d) via a micro infusion pump, whereas the Control group (n = 32) received normal saline. The cervical cord was harvested at survival times of 1, 2, 4, and 6 wk (n = 8 each). The number of surviving and nNOS-positive motoneurons at the injury level in the ventral horn was determined with NADPH-d histochemistry. Mitochondrial function at this location was measured with CcO histochemistry and densitometry. An independent t-test was applied to detect differences between the study groups at specific survival times. Result s: The Paclitaxel treatment group showed a significant relative reduction in nNOS expression at 2, 4, and 6 wk, and significantly improved mitochondrial function at 4 and 6 wk. Motoneuron survival was significantly increased at 2, 4, and 6 wk. ConclusIon: Paclitaxel has a significant neuroprotective effect against spinal motoneuron degeneration following brachial plexus avulsion injury, which involves inhibition of nNOS expression and prevention of mitochondrial dysfunction

Characterisation of protein-truncating and missense variants in PALB2 in 15 768 women from Malaysia and Singapore

Funder: National University Cancer Institute, Singapore; FundRef: http://dx.doi.org/10.13039/501100011105Background: Rare protein-truncating variants (PTVs) in partner and localiser of BRCA2 (PALB2) confer increased risk to breast cancer, but relatively few studies have reported the prevalence in South-East Asian populations. Here, we describe the prevalence of rare variants in PALB2 in a population-based study of 7840 breast cancer cases and 7928 healthy Chinese, Malay and Indian women from Malaysia and Singapore, and describe the functional impact of germline missense variants identified in this population. Methods: Mutation testing was performed on germline DNA (n=15 768) using targeted sequencing panels. The functional impact of missense variants was tested in mouse embryonic stem cell based functional assays. Results: PTVs in PALB2 were found in 0.73% of breast cancer patients and 0.14% of healthy individuals (OR=5.44; 95% CI 2.85 to 10.39, p<0.0001). In contrast, rare missense variants in PALB2 were not associated with increased risk of breast cancer. Whereas PTVs were associated with later stage of presentation and higher-grade tumours, no significant association was observed with missense variants in PALB2. However, two novel rare missense variants (p.L1027R and p.G1043V) produced unstable proteins and resulted in a decrease in homologous recombination-mediated repair of DNA double-strand breaks. Conclusion: Despite genetic and lifestyle differences between Asian and other populations, the population prevalence of PALB2 PTVs and associated relative risk of breast cancer, are similar to those reported in European populations

Transcriptomic convergence despite genomic divergence drive field cancerization in synchronous squamous tumors

IntroductionField cancerization is suggested to arise from imbalanced differentiation in individual basal progenitor cells leading to clonal expansion of mutant cells that eventually replace the epithelium, although without evidence.MethodsWe performed deep sequencing analyses to characterize the genomic and transcriptomic landscapes of field change in two patients with synchronous aerodigestive tract tumors.ResultsOur data support the emergence of numerous genetic alterations in cancer-associated genes but refutes the hypothesis that founder mutation(s) underpin this phenomenon. Mutational signature analysis identified defective homologous recombination as a common underlying mutational process unique to synchronous tumors.DiscussionOur analyses suggest a common etiologic factor defined by mutational signatures and/or transcriptomic convergence, which could provide a therapeutic opportunity

Obesity-Dependent Adipokine Chemerin Suppresses Fatty Acid Oxidation to Confer Ferroptosis Resistance

Lipid droplet formation is a defining histological feature in clear cell renal cell carcinoma (ccRCC) but the importance of this biological behavior remains enigmatic. As adipogenic trans-differentiation is an important component of ccRCC tumorigenesis, we assessed adipokine expression in ccRCC and found an obesity-dependent elevation of adipokine chemerin in ccRCC as compared to normal kidney. The roles of chemerin in regulating lipid metabolism and tumor growth were investigated in this dissertation. To functionally dissect its role in cancer, chemerin was attenuated by several approaches in vitro and in vivo, all of which led to significant impairments of tumor growth. A multi-omic approach revealed that chemerin functions by suppressing mitochondrial fatty acid oxidation, and maintains fatty acid levels which transcriptionally activate HIF-2a expression. Chemerin silencing, also led to reduction of lipid CoQ and mitochondrial complex IV, whose biogenesis are lipid-dependent, enhancing lipid reactive oxygen species production and contributed to ferroptosis. This result highlights a critical metabolic dependency unique in ccRCC.&nbsp; Collectively, targeting lipid metabolism via inhibition of a soluble adipokine is a promising pharmacological approach to greatly expand therapeutic strategies for ccRCC patients.</p

Lipid in Renal Carcinoma: Queen Bee to Target?

Clear cell renal cell carcinoma (ccRCC) is the most common renal cancer subtype, characterized by a lipid storage phenotype. We found that carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme of mitochondrial fatty acid (FA) transport, is repressed by hypoxia-inducible factors (HIFs), reducing FA oxidation (FAO). Altering lipid metabolism may be a new therapeutic avenue in ccRCC

Economic crisis : impact on the travelling habits of the Singapore tourist.

The study seeks to explore Singaporean travel habits as well as to assess how the recent economic crisis has affected these habits

GENE-07. EPIGENETIC PATHWAYS CONTROLLING HOTAIR EXPRESSION IN GLIOBLASTOMA

Glioblastoma multiforme (GBM) is the most common and aggressive malignant adult brain tumor. Long noncoding RNAs (lncRNAs) have emerged as new players in the cancer paradigm, demonstrating potential roles in both oncogenic and tumor-suppressive pathways. Utilizing single molecule sequencing, we have previously demonstrated that hundreds of lncRNAs, including HOTAIR, are strongly dysregulated in GBM and HOTAIR is critical in GBM cells proliferation. Histone deacetylase inhibitors (HDACi) are small molecules that interfere with histone tail modification, thus altering chromatin structure and epigenetic pathways. However, the mechanistic into HDAC dependent control of HOTAIR expression has remained elusive. We hypothesized that BRD4 that binds to HOTAIR promoter and Gli2 acetylation status could provide insight into regulation of HOTAIR transcription by HDACs. The HOTAIR expression after treatment of HDACi on 2 patient-derived xenografts GBM cells (PDX-10 and PDX-22) were measured via qRT-PCR and the levels of proteins were investigated via Western blot analysis. shRNA constructs targeting individual HDACs (1–7) were used to knockdown HDAC and chromatin immunoprecipitation was performed to assess the protein binding on HOTAIR. From the epigenetic drug library screening, Tricostatin A, NSC-3852, BML-281, Apicidin, M-344, Scriptaid, Oxamflatin and Vorinostat (SAHA) reduced HOTAIR levels more than 50%. HDACi treatments resulted in a dose-dependent decrease in HOTAIR expression in both newly diagnosed and recurrent GBM cells. Both BRD4 RNA and protein levels were also reduced. Furthermore, HDACi treatment resulted in an increase in acetylation and BRD4 binding at HOTAIR gene bodies but a decrease in HOTAIR promoter region. We found that the acetylation of Gli2 after HDACi treatment also prevents its usual occupancy at HOTAIR promoter and subsequent BRD4 recruitment. Importantly, our results unravel a previously unappreciated mechanism through which HDAC inhibition modulate a key regulatory step in GBM cells growth by reducing the recruitment of BRD4 and Gli2 to the HOTAIR promoter