Human papillomaviruses (HPVs) are causative agents of various diseases associated with cellular hyperproliferation, including cervical cancer, one of the most prevalent tumors in women. E7 is one of ...the two HPV-encoded oncoproteins and directs recruitment and subsequent degradation of tumor-suppressive proteins such as retinoblastoma protein (pRb) via its LxCxE motif. E7 also triggers tumorigenesis in a pRb-independent pathway through its C-terminal domain, which has yet been largely undetermined, with a lack of structural information in a complex form with a host protein. Herein, we present the crystal structure of the E7 C-terminal domain of HPV18 belonging to the high-risk HPV genotypes bound to the catalytic domain of human nonreceptor-type protein tyrosine phosphatase 14 (PTPN14). They interact directly and potently with each other, with a dissociation constant of 18.2 nM. Ensuing structural analysis revealed the molecular basis of the PTPN14-binding specificity of E7 over other protein tyrosine phosphatases and also led to the identification of PTPN21 as a direct interacting partner of E7. Disruption of HPV18 E7 binding to PTPN14 by structure-based mutagenesis impaired E7's ability to promote keratinocyte proliferation and migration. Likewise, E7 binding-defective PTPN14 was resistant for degradation via proteasome, and it was much more effective than wild-type PTPN14 in attenuating the activity of downstream effectors of Hippo signaling and negatively regulating cell proliferation, migration, and invasion when examined in HPV18-positive HeLa cells. These results therefore demonstrated the significance and therapeutic potential of the intermolecular interaction between HPV E7 and host PTPN14 in HPV-mediated cell transformation and tumorigenesis.
In Alzheimer's disease (AD), memory impairment is the most prominent feature that afflicts patients and their families. Although reactive astrocytes have been observed around amyloid plaques since ...the disease was first described, their role in memory impairment has been poorly understood. Here, we show that reactive astrocytes aberrantly and abundantly produce the inhibitory gliotransmitter GABA by monoamine oxidase-B (Maob) and abnormally release GABA through the bestrophin 1 channel. In the dentate gyrus of mouse models of AD, the released GABA reduces spike probability of granule cells by acting on presynaptic GABA receptors. Suppressing GABA production or release from reactive astrocytes fully restores the impaired spike probability, synaptic plasticity, and learning and memory in the mice. In the postmortem brain of individuals with AD, astrocytic GABA and MAOB are significantly upregulated. We propose that selective inhibition of astrocytic GABA synthesis or release may serve as an effective therapeutic strategy for treating memory impairment in AD.
Alcoholic liver disease (ALD) is a worldwide health problem and hepatocyte apoptosis has been associated with the development/progression of ALD. However, no definite effective pharmacotherapy for ...ALD is currently available. Cilostazol, a selective type III phosphodiesterase inhibitor has been shown to protect hepatocytes from ethanol-induced apoptosis. In the present study, the underlying mechanisms for the protective effects of cilostazol were examined. Primary rat hepatocytes were treated with ethanol in the presence or absence of cilostazol. Cell viability and intracellular cAMP were measured. Apoptosis was detected by Hoechst staining, TUNEL assay, and caspase-3 activity assay. The roles of cAMP and AMP-activated protein kinase (AMPK) pathways in the action of CTZ were explored using pharmacological inhibitors and siRNAs. Liver from mice received ethanol (5 g/kg body weight) by oral gavage following cilostazol treatment intraperitoneally was obtained for measurement of apoptosis and activation of AMPK pathway. Cilostazol inhibited ethanol-induced hepatocyte apoptosis and potentiated the increases in cAMP level induced by forskolin. However, the anti-apoptotic effect of cilostazol was not reversed by an inhibitor of adenylyl cyclase. Interestingly, cilostazol activated AMPK and increased the level of LC3-II, a marker of autophagy. The inhibition of AMPK abolished the effects of cilostazol on LC3-II expression and apoptosis. Moreover, the inhibition of LKB1 and CaMKK2, upstream kinases of AMPK, dampened cilostazol-inhibited apoptosis as well as AMPK activation. In conclusion, cilostazol protected hepatocytes from apoptosis induced by ethanol mainly via AMPK pathway which is regulated by both LKB1 and CaMKK2. Our results suggest that cilostazol may have potential as a promising therapeutic drug for treatment of ALD.
Intermittent fasting （IF）, a periodic energy restriction, has been shown to provide health benefits equivalent to prolonged fasting or caloric restriction. However, our understanding of the ...underlying mechanisms of IF-mediated metabolic benefits is limited. Here we show that isocaloric IF improves metabolic homeostasis against diet-induced obesity and metabolic dysfunction primarily through adipose thermogenesis in mice. IF-induced metabolic benefits require fasting-mediated increases of vascular endothelial growth factor （VEGF） expression in white adipose tissue （WAT）. Furthermore, periodic adipose-VEGF overexpression could recapitulate the metabolic improvement of IF in non-fasted animals. Importantly, fasting and adipose-VEGF induce alternative activation of adipose macrophage, which is critical for thermogenesis. Human adipose gene analysis further revealed a positive correlation of adipose VEGF-M2 macrophage-WAT browning axis. The present study uncovers the molecular mechanism of IF-mediated metabolic benefit and suggests that isocaloric IF can be a preventive and therapeutic approach against obesity and metabolic disorders.
Development of localized inflammatory environments by M1 macrophages in the cardiac infarction region exacerbates heart failure after myocardial infarction (MI). Therefore, the regulation of ...inflammation by M1 macrophages and their timely polarization toward regenerative M2 macrophages suggest an immunotherapy. Particularly, controlling cellular generation of reactive oxygen species (ROS), which cause M1 differentiation, and developing M2 macrophage phenotypes in macrophages propose a therapeutic approach. Previously, stem or dendritic cells were used in MI for their anti-inflammatory and cardioprotective potentials and showed inflammation modulation and M2 macrophage progression for cardiac repair. However, cell-based therapeutics are limited due to invasive cell isolation, time-consuming cell expansion, labor-intensive and costly ex vivo cell manipulation, and low grafting efficiency. Here, we report that graphene oxide (GO) can serve as an antioxidant and attenuate inflammation and inflammatory polarization of macrophages via reduction in intracellular ROS. In addition, GO functions as a carrier for interleukin-4 plasmid DNA (IL-4 pDNA) that propagates M2 macrophages. We synthesized a macrophage-targeting/polarizing GO complex (MGC) and demonstrated that MGC decreased ROS in immune-stimulated macrophages. Furthermore, DNA-functionalized MGC (MGC/IL-4 pDNA) polarized M1 to M2 macrophages and enhanced the secretion of cardiac repair-favorable cytokines. Accordingly, injection of MGC/IL-4 pDNA into mouse MI models attenuated inflammation, elicited early polarization toward M2 macrophages, mitigated fibrosis, and improved heart function. Taken together, the present study highlights a biological application of GO in timely modulation of the immune environment in MI for cardiac repair. Current therapy using off-the-shelf material GO may overcome the shortcomings of cell therapies for MI.
Runx2 plays essential roles in bone formation and chondrocyte maturation. Akt promotes osteoblast differentiation induced by the bone morphogenetic proteins BMP2 and enhances the function and ...transcriptional activity of Runx2. However, the precise molecular mechanism underlying the relationship between Runx2 and Akt is not well understood. In this study, we examined the role of Akt in regulating Runx2 function. We found that Akt increases the stability of Runx2 protein. However, the level of Runx2 mRNA was not affected by Akt, and we did not find any evidence for direct modification of Runx2 by Akt. Instead, we found evidence that Akt induces the phosphorylation of the Smad ubiquitination regulatory factor Smurf2 and decreases the level of Smurf2 protein through ubiquitin/proteasome‐mediated degradation of Smurf2. Akt also alleviates Smurf2‐mediated suppression of Runx2 transcriptional activity. Taken together, our results suggest that Akt regulates osteoblast differentiation, at least in part, by enhancing the protein stability and transcriptional activity of Runx2 through regulation of ubiquitin/proteasome‐mediated degradation of Smurf2.
Akt increases the stability of Runx2 protein. But the level of Runx2 mRNA was not affected by Akt and we could not detect any evidence for direct modification of Runx2 by Akt. Akt induces the phosphorylation of Smurf2 and decreases the level of Smurf2 protein through ubiquitin‐proteasome‐mediated degradation of Smurf2. Akt also alleviates Smurf2‐mediated suppression of Runx2 transcriptional activity.
Accurate estimation of shortwave net radiation (
S
n
) at a high spatial resolution is critical for regional and global land surface models. Current surface radiation budget products have fine ...temporal resolutions, but only coarse spatial resolutions that are not suitable for land applications. A hybrid algorithm was developed in this study to estimate
S
n
from MODIS data under both clear and cloudy sky conditions without requiring coarser resolution ancillary data. This algorithm was validated using ground measurements at seven sites of the SURFace RADiation budget observing network (SURFRAD) in the United States. Instantaneous
S
n
estimated by this method was also compared with GEWEX/SRB and ISCCP data, and other methods. The results indicate that our algorithm can produce
S
n
at 1-km resolution with improved accuracy and is easily implemented to generate operational global products. Daily integrated
S
n
is estimated at 1-km resolution using instantaneous
S
n
. These finer spatial resolution datasets capture the specific sequence of the redistribution of the available energy at the Earth's surface. Therefore, they support recent high resolution land surface models.
There are limited data regarding whether mortality is higher in patients with non cystic fibrosis bronchiectasis (bronchiectasis) than in those without bronchiectasis. Using 2005-2015 data from the ...Korean National Health Insurance Service, we evaluated hazard ratio (HR) for all-cause mortality in the bronchiectasis cohort relative to the matched cohort. The effect of comorbidities over the study period on the relative mortality was also assessed. All-cause mortality was significantly higher in the bronchiectasis cohort than in the matched cohort (2505/100,000 vs 2142/100,000 person-years, respectively; P < 0.001). Mortality risk was 1.15-fold greater in the bronchiectasis cohort than in the matched cohort (95% confidence interval CI 1.09-1.22); mortality was greatest among elderly patients (HR = 1.17, 95% CI 1.10-1.25) and men (HR = 1.19, 95% CI 1.10-1.29). Comorbidities over the study period significantly increased the risk of death in the bronchiectasis cohort relative to the matched cohort: asthma (adjusted HR = 1.20, 95% CI 1.11-1.30), chronic obstructive pulmonary disease (adjusted HR = 1.24, 95% CI 1.15-1.34), pneumonia (adjusted HR = 1.50, 95% CI 1.39-1.63), lung cancer (adjusted HR = 1.85, 95% CI 1.61-2.12), and cardiovascular disease (adjusted HR = 1.34, 95% CI 1.23-1.45). In contrast, there were no significant differences in the risk of death in patients without bronchiectasis-related comorbidities and the matched cohort, except in the case of non-tuberculous mycobacterial infection. In conclusion, all-cause mortality was higher in patients with bronchiectasis cohort than those without bronchiectasis, especially in elderly patients and men. Comorbidities over the study period played a major role in increasing mortality in patients with bronchiectasis relative to those without bronchiectasis.
PDF
