Molecular signature of cardiac remodeling associated with Polymerase Gamma mutation

AIMS

Metabolic function/dysfunction is central to aging biology. This is well illustrated by the Polymerase Gamma (POLG) mutant mouse where a key residue of the mitochondrial DNA polymerase is mutated (D257A), causing loss of mitochondrial DNA stability and dramatically accelerated aging processes. Given known cardiac phenotypes in the POLG mutant, we sought to characterize the course of cardiac dysfunction in the POLG mutant to guide future intervention studies.

MATERIALS AND METHODS

Cardiac echocardiography and terminal hemodynamic analyses were used to define the course of dysfunction in the right and left cardiac ventricles in the POLG mutant. We also conducted RNA-seq analysis on cardiac right ventricles to identify mechanisms engaged by severe metabolic dysfunction and compared this analysis to several publically available datasets.

KEY FINDINGS

Interesting sex differences were noted as female POLG mutants died earlier than male POLG mutants and LV chamber diameters were impacted earlier in females than males. Moreover, male mutants showed LV wall thinning while female mutant LV walls were thicker. Both males and females displayed significant RV hypertrophy. POLG mutants displayed a gene expression pattern associated with inflammation, fibrosis, and heart failure. Finally, comparative omics analyses of publically available data provide additional mechanistic and therapeutic insights.

SIGNIFICANCE

Aging-associated cardiac dysfunction is a growing clinical problem. This work uncovers sex-specific cardiac responses to severe metabolic dysfunction that are reminiscent of patterns seen in human heart failure and provides insights to the molecular mechanisms engaged downstream of severe metabolic dysfunction that warrant further investigation.

Significance of mitochondrial activity in neurogenesis and neurodegenerative diseases

Mitochondria play a multidimensional role in the function and the vitality of the neurological system. From the generation of neural stem cells to the maintenance of neurons and their ultimate demise, mitochondria play a critical role in regulating our neural pathways' homeostasis, a task that is critical to our cognitive health and neurological well-being. Mitochondria provide energy via oxidative phosphorylation for the neurotransmission and generation of an action potential along the neuron's axon. This paper will first review and examine the molecular subtleties of the mitochondria's role in neurogenesis and neuron vitality, as well as outlining the impact of defective mitochondria in neural aging. The authors will then summarize neurodegenerative diseases related to either neurogenesis or homeostatic dysfunction. Because of the significant detriment neurodegenerative diseases have on the quality of life, it is essential to understand their etiology and ongoing molecular mechanics. The mitochondrial role in neurogenesis and neuron vitality is essential. Dissecting and understanding this organelle's role in the genesis and homeostasis of neurons should assist in finding pharmaceutical targets for neurodegenerative diseases.

The Mitochondrial Deubiquitinase USP30 Regulates AKT/mTOR Signaling

Mitophagy is an intracellular mechanism to maintain mitochondrial health by removing dysfunctional mitochondria. The E3 ligase Parkin ubiquitinates the membrane proteins on targeted mitochondria to initiate mitophagy, whereas USP30 antagonizes Parkin-dependent mitophagy by removing ubiquitin from Parkin substrates. The AKT/mTOR signaling is a master regulator of cell proliferation, differentiation, apoptosis, and autophagy. Although mounting evidence suggests that perturbations in the AKT/mTOR signaling pathway may contribute to mitophagy regulation, the specific mechanisms between Parkin/USP30 and AKT/mTOR signaling have not been elucidated. In this study, we employ a set of genetic reagents to investigate the role of Parkin and USP30 in regulating the AKT/mTOR signaling during mitophagy. We demonstrated that, in the setting of mitochondrial stress, the AKT/mTOR signaling is regulated, at least in part, by the activity of Parkin and USP30. Parkin inhibits AKT/mTOR signaling following an in vitro mitochondrial stress, thereby promoting apoptosis. However, USP30 overexpression antagonizes the activity of Parkin to sustain AKT/mTOR activity and inhibit apoptosis. These findings provide new insights into Parkin and USP30’s role in apoptosis and suggest that inhibiting USP30 might provide a specific strategy to synergize with AKT/mTOR inhibitors in cancer treatment.

Detection of blaKPC and blaNDM genes by duplex PCR with lateral flow dipsticks from sterile body fluid samples

Duplex polymerase chain reaction with lateral flow dipsticks (duplex PCR-LFD) was developed for the simultaneous detection of beta-lactamase Klebsiella pneumoniae carbapenemase (bla_KPC ) and beta-lactamase New Dehli metallo-beta-lactamase (bla_NDM ) genes in body fluid samples. This method was validated using well-characterized isolates. The assessment of the specificity of duplex PCR-LFD showed that there was no cross-reactivity with other targets. The detection limit of the duplex PCR-LFD assay was 20 CFU per ml for bla_KPC and bla_NDM . Among 177 sterile body fluid samples tested by the duplex PCR-LFD assay, 40 were bla_KPC -positive and five were bla_NDM -positive. The results obtained from 122 corresponding Gram-negative bacteria which were isolated from these clinical samples and tested by duplex PCR-LFD assay showed that there were 37 strains carrying bla_KPC genes in 40 bla_KPC -positive samples and three strains carrying bla_NDM genes in five bla_NDM -positive samples. Statistical analysis indicated that there was no significant difference between the direct detection of bla_KPC and bla_NDM genes in clinical sterile body fluid samples and their corresponding clinical isolates. Therefore, duplex PCR-LFD can be effective for the simultaneous detection of bla_KPC and bla_NDM in clinical isolates and directly from clinical samples, which may be helpful for the administration of appropriate antimicrobial treatment.

Hyper-Synergistic Antifungal Activity of Rapamycin and Peptide-Like Compounds against Candida albicans Orthogonally via Tor1 Kinase

Candida albicans is a life-threatening, opportunistic fungal pathogen with a high mortality rate, especially within the immunocompromised populations. Multidrug resistance combined with limited antifungal drugs even worsens the situation. Given the facts that the current drug discovery strategies fail to deliver sufficient antifungals for the emerging multidrug resistance, we urgently need to develop novel approaches. By systematically investigating what caused the different antifungal activity of rapamycin in RPMI 1640 and YPD, we discovered that peptide-like compounds can generate a hyper-synergistic antifungal effect with rapamycin on both azole-resistant and sensitive clinical C. albicans isolates. The minimum inhibitory concentration (MIC) of rapamycin reaches as low as 2.14 nM (2^-9 μg/mL), distinguishing this drug combination as a hyper-synergism by having a fractional inhibitory concentration (FIC) index ≤ 0.05 from the traditional defined synergism with an FIC index < 0.5. Further studies reveal that this hyper-synergism orthogonally targets the protein Tor1 and affects the TOR signaling pathway in C. albicans, very likely without crosstalk to the stress response, Ras/cAMP/PKA, or calcineurin signaling pathways. These results lead to a novel strategy of controlling drug resistant C. albicans infection in the immunocompromised populations. Instead of prophylactically administering other antifungals with undesirable side-effects for extended durations, we now only need to coadminister some nontoxic peptide additives. The novel antifungal strategy approached in this study not only provides a new therapeutic method to control fungal infections in rapamycin-taking immunocompromised patients but also mitigates the immunosuppressive side-effects of rapamycin, repurposing rapamycin as an antifungal agent with wide applications.

[Genomic investigation of human Streptococcus suis infection in Shandong Province]

To investigate Streptococcus suis (S.suis) isolated from patients in Shandong province using genomic epidemiology and pathogenologic analysis. To provide the foundation to establish reasonable and accurate prevention and control measures of human S. suis infection. Molecular typing, whole genome phylogenetic tree, virulence gene typing, antibiotic resistance profile and mobile genetic elements carrying antibiotic resistance genes of isolated S. suis strains were investigated. The pathogenicity of isolated strains was also evaluated by comparing their capacity to induce pro-inflammatory cytokine production in vitro. S. suis infections in Shandong province were predominantly due to serotype 2 and sequence type 1 strains. The major symptoms were meningitis. The studied strains could be divided into five lineages. All strains belong to highly pathogenic type in Shandong province,Strains from lineage 2 possessed higher capacity to stimulate pro-inflammatory cytokine production than other strains did, even though other strains belong to highly pathogenic strains. In addition, multiple antibiotic resistance genes and corresponding mobile genetic elements werewidespread in S. suis strains from Shandong province, except strains from lineage 3. High diversities in genome, evolutionary path and pathogenicity of S. suis strains from Shandong province were revealed. It was necessary to surveillant the S. suis strain in genomic level.

Berberine reverses multidrug resistance in Candida albicans by hijacking the drug efflux pump Mdr1p

Clinical use of antimicrobials faces great challenges from the emergence of multidrug-resistant pathogens. The overexpression of drug efflux pumps is one of the major contributors to multidrug resistance (MDR). Reversing the function of drug efflux pumps is a promising approach to overcome MDR. In the life-threatening fungal pathogen Candida albicans, the major facilitator superfamily (MFS) transporter Mdr1p can excrete many structurally unrelated antifungals, leading to MDR. Here we report a counterintuitive case of reversing MDR in C. albicans by using a natural product berberine to hijack the overexpressed Mdr1p for its own importation. Moreover, we illustrate that the imported berberine accumulates in mitochondria and compromises the mitochondrial function by impairing mitochondrial membrane potential and mitochondrial Complex I. This results in the selective elimination of Mdr1p overexpressed C. albicans cells. Furthermore, we show that berberine treatment can prolong the mean survival time of mice with blood-borne dissemination of Mdr1p overexpressed multidrug-resistant candidiasis. This study provides a potential direction of novel anti-MDR drug discovery by screening for multidrug efflux pump converters.

Abstract MP231: Long Non-coding Rna Camirt Plays A Sentinel Role In Aging-related Heart Failure Via Interaction With Phb2 To Modulate Mitophagy Signaling In The Heart

Background: Mitochondrial dysfunction is an important risk factor for heart failure in elderly people. Mitophagy, a physiological process that controls the removal of damaged mitochondria, is compromised in aging or failing hearts. In this study, we examined the physiological role of a cardiac-specific lncRNA Camirt that can potentially modulate mitophagy in the heart.

Methods and Results: RNA-seq analysis and RT-PCR reveal a lncRNA is highly expressed in both mouse and human hearts, with undetectable levels in other vital organs. Furthermore, Real time qPCR was used to examine the expression of lncRNA in different animal models and in human hearts, which results showed that the expression of this lncRNA is decreased in aging mouse and human hearts, and failing mouse hearts induced by isoproterenol and doxorubicin. RNA pull-down and RNA-binding protein immunoprecipitation assays identify prohibitin-2 (Phb2), a known mitophagy receptor, as a binding partner for this lncRNA. Thus, we name this novel lncRNA as a cardiac-specific mitophagy-associated RNA transcript (Camirt). Camirt conditional (flox) knockout mice were created via CRISPR /Cas9 technology, and subjected to the longitudinal echocardiographic and survival studies. Mice with cardiac specific deletion of Camirt (Camirt-cKO) display progressive heart failure and die within 12 month after birth. RNA sequencing and gene ontology analysis revealed that genes involved in mitophagy signaling were significantly altered in the Camirt-cKO hearts compared with the littermate wild type mice. Transmission electron microscopy were used to examine the mitochondrial morphology in mouse hearts, and reveal excessive accumulation of mitolysosomes in cardiomyocytes derived from the Camirt-cKO mice. In vitro study with Annexin-V/PI staining showed an increased number of live cells and decreased number of apoptotic cells in cultured neonatal cardiomyocytes with overexpression of Camirt following oxidative stress induced by treatment with H2O2. Increased autophagy (or mitophagy) activity was observed in HL-1 cells with stable overexpression of Camirt and in the presence of chloroquine (an inhibitor for the lysosome degradation). While reduced Camirt expression via shRNA knock-down leads to compromised mitophagy activity in HL-1 cells. Further biochemical studies support the function of Camirt/Phb2 in maintenance of mitochondria function and mitophagy signaling under stress conditions.

Conclusion: Overall, our results suggested that Camirt plays a sentinel role in aging-related heart failure via interaction with Phb2 to modulate mitophagy signaling in the heart. Future studies will focus on elucidating the in vivo role and mechanisms of Camirt in modulation of mitophagy under natural aging or stress-induced pathologic conditions using the loss- or gain-of-function of Camirt mouse models.

[Survival analysis of silicosis patients in Wuxi City]

Objective: To analyze the living condition and influencing factors of silicosis patients in Wuxi City form 1975 to 2019. Methods: Through the monitoring of death causes of residents, the paper-based materials and online report system of diagnosis over the years, and the combination of public security and human social system to obtain 3721 cases of silicosis patients as subjects form August to December 2019. And the combination of Kaplan Meier method and life table method were used to carry out single factor survival analysis. Through Cox regression model to analyze the factors affecting the survival time of patients. Results: From 1975 to 2019, 3721 cases of silicosis and 1274 deaths have been reported in Wuxi City, with a mortality rate of 34.24% and a median survival time of 30.9 years. With the development of diagnosis time, the mortality decreased significantly (χ(2)=747.75, P<0.05) . Compared with the first stage silicosis patients, the risk of decreased survival time of the third stage silicosis patients increased (HR=1.486, P<0.05) . Compared with the non-smoking patients, the risk of decreased survival time of the smoking patients increased (HR=1.136, P<0.05) . Compared with the patients who were less than 30 years old, the risk of decreased survival time of patients with 40-49 years old, 50-59 years old and more than 60 years old were increased (HR=9.641, 13.650, 26.794, P<0.05) . Compared with the patients who received industrial and commercial insurance, the risk of decreased survival time of patients who received compensation from employers, basic medical insurance for urban and rural residents, other social compensation and no compensation were increased (HR=3.137, 3.119, 5.129, 8.442, P<0.05) . Conclusion: The survival time of silicosis patients is related to the stage of silicosis, smoking condition, age of onset and social compensation. We should focus on controlling the above risk factors so as to improve the quality of life of patients and prolong their lives.

Pharmacological inhibition of USP30 activates tissue-specific mitophagy

AIM

Mitophagy is the regulated process that targets damaged or dysfunctional mitochondria for lysosomal-mediated removal. This process is an essential element of mitochondrial quality control, and dysregulation of mitophagy may contribute to a host of diseases, most notably neurodegenerative conditions such as Parkinson's disease. Mitochondria targeted for mitophagic destruction are molecularly marked by the ubiquitination of several outer mitochondrial membrane (OMM) proteins. This ubiquitination is positively regulated, in part, by the mitochondrial-targeted kinase PINK1 and the E3 ubiquitin ligase Parkin. In contrast, the reverse phenomenon, deubiquitination, removes ubiquitin from Parkin substrates embedded in the OMM proteins, antagonizing mitophagy. Recent evidence suggests that the mitochondrial deubiquitinase USP30 negatively regulates Parkin-mediated mitophagy, providing opportunities to identify USP30 inhibitors and test for their effects in augmenting mitophagy. Here we will characterize a USP30 inhibitor and demonstrate how the pharmacological inhibition of USP30 can augment stress-induced mitophagic flux.

METHODS

We have conducted mitophagy and mitochondrial analyses in cultured cells. We have determined the plasma pharmacokinetics of the USP30 inhibitor in mice and conducted analyses using the mt-Keima mice to measure in vivo mitophagy directly.

RESULTS

The compound has minimal mitochondrial toxicity in cultured cells and is tolerated well in mice. Interestingly, we demonstrated tissue-specific induction of mitophagy following USP30 pharmacological inhibition. In particular, pharmacological inhibition of USP30 induces a significant increase in cardiac mitophagy without detriment to cardiac function.

CONCLUSION

Our data support the evidence that USP30 inhibition may serve as a specific strategy to selectively increase mitophagic flux, allowing for the development of novel therapeutic approaches.

Inactivation of lncRNA HOTAIRM1 caused by histone methyltransferase RIZ1 accelerated the proliferation and invasion of liver cancer

OBJECTIVE

Liver cancer is the second most common cause of cancer death, causing more than 700,000 deaths every year. It has been demonstrated that Long non-coding RNA (LncRNA) plays an important regulatory role in a series of diseases. However, the regulatory mechanism of LncRNAs in liver cancer has not been fully elucidated. The purpose of this study was to explore the interaction of lncRNA HOTAIRM1 and aberrant histone modification in liver cancer.

MATERIALS AND METHODS

qRT-PCR was used to detect the expression levels of RIZ1 and miR-125b in liver cancer cells. Cell proliferation was measured using the CCK8 assay. ChIP-Real-time PCR confirmed the binding site of the promoter of HOTAIRM1 by H3K9me1. The direct target of HOTAIRM1 and miR-125b in liver cancer cells was measured by a luciferase reporter assay. Cell proliferation was detected by Cell Counting Kit-8 (CCK8). Cell invasion was measured by transwell assays and cell migration was detected by wound healing assay.

RESULTS

The expression level of RIZ1 and miR-125b was upregulated, and HOTAIRM1 was downregulated in liver cancer cells. Transwell and CCK-8 assay showed that RIZ1 expression is associated with the proliferation, invasion and migration of liver cancer cells, silencing of RIZ1 inhibited cell proliferation, migration, and invasion in HEPG2 and HCC-LM3 cells. RIZ1 interference could significantly inhibit H3K9me1 expression. H3K9me1 protein can bind to HOTAIRM1 promoter directly. Furthermore, the bioinformatics prediction and luciferase assay demonstrated that miR-125b can interact with HOTAIRM1 by direct binding. HOTAIRM1 down-expression promoted HEPG2 cell growth and metastasis, which was further strengthened following the co-transfection of miR-125b. Furthermore, overexpressed HOTAIRM1 inhibited HCC-LM3 cell growth and metastasis and a complete reversal of the results seen when transfected with miR-125b.

CONCLUSIONS

For the first time, we found that RIZ1 was upregulated in liver cancer cells and RIZ1-mediated H3K9me1 enrichment on the HOTAIRM1 promoter regulated the growth and metastasis of liver cancer cells by targeting miR-125b, which could further accelerate tumor proliferation, migration and invasion. It may serve as a therapeutic marker for liver cancer treatment.

[Comparison of different reconstruction procedures after distal gastrectomy in patients with gastric cancer]

Objective: To systematically compare the effect of Roux-en-Y with Billroth Ⅰ or Billroth Ⅱ in gastric cancer patients after distal gastrectomy by meta-analysis. Methods: Systematic search was conducted on the relevant electronic databases of Pubmed, Embase, Wanfang Database, CNKI and VIP from the established time to August 18, 2019. The randomized controlled trials about comparison of Roux-en-Y with Billroth Ⅰ or Billroth Ⅱ were strictly screened and analyzed by the software of Revman 5.3. Procedure and postoperative outcomes were analyzed, respectively. Results: A total of 783 relevant literatures were systematically retrieved, and 6 randomized controlled trials, including 954 patients, finally met the inclusion criteria after strict screening. The results of meta-analysis showed that operative time of Billroth Ⅰ was significantly shorter than that of Roux-en-Y (MD=-37.60, 95%CI:-50.79--24.40, P<0.001), intraoperative bleeding (MD=-21.64, 95%CI:-32.20--11.07, P<0.001) and the number of delayed gastric emptying (RR=0.52, 95%CI: 0.31-0.86, P=0.01) of Billroth Ⅰ were both significantly less than those of Roux-en-Y, while bile reflux (RR=8.17, 95%CI: 2.21-31.53, P=0.002) and residual gastritis (RR=1.75, 95%CI:1.43-2.14, P<0.000 01) of Billroth Ⅰ were both significantly higher than those of Roux-en-Y, other outcomes showed no significant difference. Compared with Roux-en-Y, operative time of Billroth Ⅱ was significantly shorter (MD=-19.73, 95%CI:-32.82--6.64, P=0.003), while bile reflux (RR=17.63, 95%CI: 4.50-69.02, P<0.001), residual gastritis (RR=1.94, 95%CI:1.15-3.26, P=0.01) and reflux esophagitis (RR=3.13, 95%CI: 1.31-7.45, P=0.01) of Billroth Ⅱ were all significantly higher, and there was no significant difference in other outcomes. Conclusion: Compared with Billroth Ⅰ and Billroth Ⅱ, the operation time of Roux-en-Y in gastric cancer patients undergoing distal gastrectomy is longer, but the incidences of bile reflux and residual gastritis are both lower, and the postoperative quality of life seems better.

Zika Virus-Induced Neuronal Apoptosis via Increased Mitochondrial Fragmentation

The 2015 to 2016 outbreak of Zika virus (ZIKV) infections in the Americas coincided with a dramatic increase in neurodevelopmental abnormalities, including fetal microcephaly, in newborns born to infected women. In this study, we observed mitochondrial fragmentation and disrupted mitochondrial membrane potential after 24 h of ZIKV infection in human neural stem cells and the SNB-19 glioblastoma cell line. The severity of these changes correlated with the amount of ZIKV proteins expressed in infected cells. ZIKV infection also decreased the levels of mitofusin 2, which modulates mitochondria fusion. Mitochondrial division inhibitor 1 (Mdivi-1), a small molecule inhibiting mitochondria fission, ameliorated mitochondria disruptions and reduced cell death in ZIKV-infected cells. Collectively, this study suggests that abnormal mitochondrial fragmentation contributes to ZIKV-induced neuronal cell death; rebalancing mitochondrial dynamics of fission-fusion could be a therapeutic strategy for drug development to treat ZIKV-mediated neuronal apoptosis.

Predicting non-elective hospital readmission or death using a composite assessment of cognitive impairment and frailty in elderly inpatients with cardiovascular diseases

Background

Cardiovascular disease (CVD) and related complications are significant healthcare problems in the growing elderly population. Metabolic factors are the predominant risk factors for CVD, sedentary behaviour and physical inactivity are major modifiable risk factors for CVD. Age-associated cognitive decline and impairment are associated with an increased mortality. Cognitive and physical components of frailty have pathophysiologic rationale as risk factors for CVD. There is a clinical need to identify more practical screens that can assist us to definite cognitive impairment and physical frailty, then to determine which patients with CVD are at high risk of adverse outcomes, early management of these high-risk patients can reduce readmission rates, healthcare spending, and improve quality of care.

Purpose

We aimed to assess the utility of a combination developed using the mini-mental state examination + clock drawing test and the Fried phenotype for predicting non-elective hospital readmission or death within 6-month in elderly inpatients with CVD.

Methods

A single center prospective cohort was conducted between September 2018 and February 2019. Inpatients aged 65 years or older were recruited. All enrolled patients received a comprehensive geriatric assessment during hospitalization. The Kaplan-Meier curves were used to estimate the cumulative incidence of events. The multivariate Cox regression model was used to analyze the association between frailty and cognitive status and the non-elective hospital readmission or death.

Results

A total of 542 patients were included; and a total of 113 patients (20.9%) died or were readmitted at 6-month. Overall 20% screened positive for cognitive impairment, including 8% were cognitive impairment combined with physical frailty, which were more older, more common in women and non-married group, had a lower education and a higher risk of malnutrition. Frail participants with normal (hazard ratio [HR]: 1.73, 95% confidence intervals [CI]: 1.06–2.82, P=0.028) and impaired cognition (HR: 2.50, 95% CI: 1.27–4.91, P=0.008) had a higher risk of non-elective hospital readmission or death than robust patients, after adjustment for age, sex, education level, marital status, the presence of diabetes mellitus, heart failure, and previous stroke.

Conclusions

The presence of physical frailty and cognitive frailty were powerful predictors of non-elective hospital readmission or death in elderly inpatients with CVD, and taking cognitive impairment into account in the frailty model may allow better prediction of adverse outcomes of frailty in the short time.

Kaplan-Meier survival curves

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Beijing Municipal Science & Technology Commission, Chinese Academy of Medical Sciences

Correlation between COX-2 gene polymorphism and susceptibility to nasopharyngeal carcinoma

OBJECTIVE

The aim of this study was to investigate cyclooxygenase-2 (COX-2) gene polymorphism in peripheral blood cells of patients with nasopharyngeal carcinoma (NPC) and normal people, and to explore the correlation between polymorphism and the occurrence of NPC.

PATIENTS AND METHODS

The genotype and allele distributions of gene loci COX-2-899 (G/C) and COX-2-1195 (G/A) in peripheral blood of 56 normal people and 114 NPC patients were analyzed via reverse transcription-polymerase chain reaction (RT-PCR). The genetic equilibrium was detected by TaqMan genotyping technique. Meanwhile, the risk factors for NPC were analyzed via multivariate logistic regression analysis. Subsequently, the effects of risk factors, clinical features, and gene polymorphism of NPC on the prognosis and survival of patients were analyzed using univariate and multivariate COX regression analysis. Finally, the correlation of smoking, Epstein-Barr (EB) virus infection and COX-2-1195 gene polymorphism with NPC was explored via χ2-test.

RESULTS

There was a significant difference in the genotype and allele distributions at COX-2-1195 (G/A) between the two groups (p<0.05). However, no significant differences were observed at COX-2-899 (G/C) between the two groups (p>0.05). According to the results of univariate and multivariate COX regression analysis, smoking and EB virus infection were risk factors for NPC (p<0.05). The χ2-test indicated that there was an evident gene polymorphism at COX-2-1195 in smokers and EB virus-infected people compared to non-smokers and non-infected people (p<0.05).

CONCLUSIONS

COX-2-1195 gene polymorphism is associated with susceptibility to NPC. Smoking and EB virus infection are major risk factors for NPC, both of which can affect COX-2-1195 gene polymorphism.

Volcanic origin for Younger Dryas geochemical anomalies ca. 12,900 cal B.P

The Younger Dryas (YD) abrupt cooling event ca. 12.9 ± 0.1 ka is associated with substantial meltwater input into the North Atlantic Ocean, reversing deglacial warming. One controversial and prevailing hypothesis is that a bolide impact or airburst is responsible for these environmental changes. Here, highly siderophile element (HSE; Os, Ir, Ru, Pt, Pd, and Re) abundances and 187Os/188Os ratios were obtained in a well-dated sediment section at Hall's Cave, TX, USA to test this hypothesis. In Hall's Cave, layers below, above, and in the YD have 187Os/188Os ratios consistent with incorporation of extraterrestrial or mantle-derived material. The HSE abundances indicate that these layers contain volcanic gas aerosols and not extraterrestrial materials. The most likely explanation is that episodic, distant volcanic emissions were deposited in Hall's Cave sediments. Coupled 187Os/188Os ratios and HSE concentration data at close stratigraphic intervals are required to effectively differentiate between bolide and volcanic origins.

A Healthy Heart and a Healthy Brain: Looking at Mitophagy

Mitochondrial dysfunction is a hallmark of aging and is a major contributor to neurodegenerative diseases and various cardiovascular disorders. Mitophagy, a specialized autophagic pathway to remove damaged mitochondria, provides a critical mechanism to maintain mitochondrial quality. This function has been implicated in a tissue's ability to appropriately respond to metabolic and to bioenergetic stress, as well as to recover from mitochondrial damage. A global decline in mitophagic flux has been postulated to be linked to pathological alterations that occur in the heart and the brain as well as a general age-dependent decline in organ function. Cellular observation suggests multiple mechanistically distinct pathways converge upon and activate mitophagy. Over the past decade, additional molecular components within mitophagy have been discovered, including several disease-associated genes that are functionally implicated in mitophagy. However, the pathophysiological role of mitophagy, and how it is regulated within normal physiology or various disease states, is less well established. Here, we will review the evidence that a decline in mitophagy contributes to impaired mitochondrial homeostasis and may be particularly detrimental to postmitotic neurons and cardiomyocytes. We will discuss mitophagy's pathological significance in both neurodegenerative diseases and cardiovascular disorders. Additionally, signaling pathways regulating mitophagy are reviewed, with emphasis placed on how these pathways might contribute to disease progression. Understanding mitophagy's role in the mechanisms of disease pathogenesis should allow for the development of more efficient strategies to battle pathological conditions associated with mitochondrial dysfunction.

Mitophagy in cardiovascular homeostasis

Mitochondria are essential organelles that generate energy to fuel myocardial contraction. Accumulating evidence also suggests that, in the heart, mitochondria may contribute to specific aspects of disease progression through the regulations of specific metabolic intermediates, as well as the transcriptional and epigenetic states of cells. If damaged, the mitochondria and their related pathways are hindered, which may result in or contribute to the development of a wide range of cardiovascular diseases. Therefore, the maintenance of cardiac mitochondrial function and integrity through specific mitochondrial quality control mechanisms is critical for cardiovascular health. Mitophagy is part of the overall mitochondrial quality control process, and acts as a specialized autophagic pathway that mediates the lysosomal clearance of damaged mitochondria. In response to cardiac stress and injury, the pathways associated with mitophagy are triggered resulting in the removal of damaged mitochondrial, thereby maintaining cardiac homeostasis. In addition, recent studies have demonstrated an essential role for mitophagy in both developmental and disease-related metabolic transitioning of cardiac mitochondria. Here, we discuss the physiological and the pathological roles of mitophagy in the heart, the underlying molecular mechanisms, as well as potential therapeutic strategies based on mitophagic modulation.