Myricetin attenuates hypoxia-induced inflammation in human adipocytes

BACKGROUND

Adipose tissue hypoxia plays a crucial role in the development of chronic low-grade systemic inflammation which has been associated with the pathogenesis of obesity-related diseases. Myricetin is a natural compound present in numerous plant-based foods with presumed anti-inflammatory and beneficial health effects. The impact of this flavonoid on hypoxia-induced expression of inflammatory adipokines and hypoxia-regulated pathways is unknown so far and has been addressed in the present study.

METHODS

Differentiated human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were cultured with or without myricetin under normoxic and hypoxic conditions for varying time periods. The effect of hypoxia and myricetin on the expression of the investigated adipokines was measured by real-time RT-PCR. Western blot analysis was used for the detection of transcription factors involved in hypoxia-regulated pathways.

RESULTS

Myricetin interfered in the hypoxia-induced regulation of adipokines and the underlying pathways, which are involved in transmitting the inflammatory response. It strongly repressed hypoxia-induced expression of apelin, leptin, chemerin, asprosin, and DPP-4 and HIF-1α accumulation in the nucleus was diminished. Furthermore, the activation of the key regulators in the inflammatory response NF-κB, Akt, and CREB was suppressed by myricetin under hypoxic conditions. Myricetin also decreased hypoxia-induced accumulation of the pro-tumorigenic transcription factors Snail and Slug in the nucleus.

CONCLUSION

Taken together, our results indicated that myricetin regulated hypoxia-induced expression of adipokines and hypoxia-regulated pathways in human adipocytes. Our study therefore provided evidence of the anti-inflammatory effects of myricetin in hypoxia-treated human adipocytes.

Circulating glypican-4 is a new predictor of all-cause mortality in patients with heart failure

BACKGROUND

Heart failure confers a high burden of morbidity and mortality. However, risk prediction in heart failure patients still is limited. Blood-based biomarkers hold promise to improve clinical risk assessment. Recently we have identified circulating glypican-4 (GPC4) as a significant predictor of mortality in coronary angiography patients and patients with peripheral artery disease. The impact of serum GPC4 on mortality in patients with heart failure is unknown and is addressed in this prospective cohort study.

METHODS

We prospectively recorded all-cause mortality in 288 patients with heart failure. GPC4 levels were measured using an enzyme-linked immunosorbent assay at baseline.

RESULTS

During the 24-month follow-up period, 28.1% (n = 81) of the patients died. Serum GPC4 significantly predicted all-cause mortality (hazard ratio (HR) per doublingof GPC4 = 3.57 [2.31-5.53]; P < 0.001). Subgroup analysis showed that GPC4 was significantly associated with all-cause mortality in patients with reduced ejection fraction (HR per doubling = 3.25 [1.75-6.04]; P < 0.001) as well as in those with preserved ejection fraction (HR per doubling = 3.07 [1.22-7.70]; P = 0.017). The association between serum GPC4 and all-cause mortality remained significant in multivariable Cox regression analysis correcting for traditional risk factors (P = 0.035). Results from C-statistics indicated an additional prognostic value of GPC4 relative to NT-proBNP for the prediction of two-year all-cause mortality (P = 0.030).

CONCLUSION

Circulating GPC4 independently predicts all-cause mortality in patients with heart failure.

Plasma apolipoprotein M predicts overall survival in metastatic breast cancer patients

PURPOSE

Apolipoprotein M (APOM) is a plasma apolipoprotein closely involved with lipid metabolism and inflammation. In vitro studies suggest that APOM may also have a tumor-suppressive role in breast cancer. In the present study, we aimed to evaluate the impact of plasma APOM levels on the prognosis of breast cancer patients.

METHODS

We measured APOM levels using an enzyme-linked immunosorbent assay in 75 patients with ER-positive/HER2-negative metastatic breast cancer. The endpoint was overall survival (OS) at 24 months.

RESULTS

During the 24-month follow-up period, 34.7% of the patients died. Baseline APOM levels were significantly reduced in patients who deceased during follow-up compared to survivors (42.7 ± 14.5 µg/mL versus 52.2 ± 13.8 µg/mL; P = 0.003). Cox regression analysis showed a hazard ratio of 0.30 [95% confidence interval 0.15-0.61]; P < 0.001 per doubling of APOM levels. Correction for age, C-reactive protein, menopausal state, histology of the primary tumor, metastatic site, number of metastases, endocrine resistance, scheduled therapy line, and kind of scheduled therapy indicated that circulating APOM predicted OS independently of these parameters (HRper doubling = 0.23 [0.09-0.56; P = 0.001).

CONCLUSIONS

Our study suggests that circulating APOM is significantly linked with reduced mortality in metastatic breast cancer patients.

Cell-free circulating RAS mutation concentrations significantly impact the survival of metastatic colorectal cancer patients

PURPOSE

RAS mutations are predictors of an adverse outcome in EGFR-targeted therapies and have been proposed as prognostic biomarkers of survival in metastatic colorectal cancer (mCRC). The analysis of circulating tumor DNA from plasma samples, known as liquid biopsies, has indicated that the RAS mutation status may change over time, potentially affecting patients' prognosis. To further evaluate the clinical validity of RAS mutation retesting using liquid biopsies, we prospectively investigated the impact of the circulating quantitative RAS mutation status on the course of mCRC.

METHODS

The present study included 81 consecutively recruited patients with mCRC. We used targeted next-generation sequencing of circulating cell-free DNA to determine and quantify plasma RAS mutation status.

RESULTS

Patients with a RAS mutation detected by liquid biopsy (37%; n = 30) were at increased risk of death during the follow-up period compared to RAS wild-type patients. Patients with evidence of a RAS mutation in the primary tumor but a putative RAS mutation loss in plasma (28%; n = 11) showed a prolonged survival compared to patients with a preserved RAS mutation status. Also, circulating RAS mutation concentrations significantly affected the outcome: The mortality risk of patients with a high RAS mutation concentration increased fivefold compared to subjects with a putative RAS mutation loss or low RAS mutation concentration.

CONCLUSION

Our results emphasize the clinical value of circulating RAS mutations in managing mCRC.

Circulating glypican-4 is a predictor of 24-month overall survival in metastatic breast cancer

BACKGROUND & OBJECTIVE

Endocrine treatment combined with CDK4/6 inhibitors is the preferred treatment strategy in patients presenting with ER-positive/HER2-negative breast cancer, but the clinical course remains highly variable among individual patients. There is an unmet need for prognostic or predictive biomarkers in this important group of patients. Recently, we have identified circulating glypican-4 (GPC4) as a new biomarker of inferior outcomes in patients with metastatic colorectal cancer. The impact of plasma GPC4 levels on the survival of breast cancer patients is unknown and has been addressed in the present study.

METHODS

Our study included 47 patients with ER-positive/HER2-negative metastatic breast cancer prior to treatment with CDK4/6 inhibitors combined with endocrine therapy. The endpoint was overall survival (OS) at 24 months. GPC4 levels were measured in plasma using an enzyme-linked immunosorbent assay.

RESULTS

Increased circulating GPC4 levels were significantly linked to advanced age, postmenopausal state, visceral metastases, and invasive lobular carcinoma. During the two-year observational follow-up period, 25.5 % of patients died. The area under the receiver operating characteristic curve (ROC-AUC) analysis revealed an AUC of 0.713 [0.555-0.871]; P=0.029 for OS and an optimal cut-off value of GPC4 for predicting OS of 4.77 ng/mL. No patient showing GPC4 values below this cut-off died during the observational period. Cox regression analysis showed a hazard ratio of 2.14 [95% confidence interval: 1.24-3.67]; P=0.006 for one standard deviation change of plasma GPC4.

CONCLUSIONS

In conclusion, our study suggests circulating GPC4 as a significant predictor of poor survival in metastatic breast cancer patients.

Lipid profiles of patients with manifest coronary versus peripheral atherosclerosis - Is there a difference?

AIM

Peripheral arterial disease (PAD) and coronary artery disease (CAD) are both caused by atherosclerosis. Serum lipids and lipoproteins are predictive of the development of atherosclerosis but it is not clear if they differ in the two manifestations, PAD and CAD. We tested whether a more detailed characterization of the lipid and lipoprotein patterns of PAD and CAD allows a clear differentiation between the two atherosclerotic phenotypes.

METHODS

A cohort of 274 statin-naïve patients with either newly diagnosed imaging proven PAD (n = 89) or stable CAD (n = 185) was characterized using nuclear magnetic resonance- and liquid chromatography-tandem mass spectrometry-based advanced lipid and lipoprotein analysis. An independent cohort of 1239 patients with PAD and CAD was used for validation.

RESULTS

We found a significant difference in markers of inflammation as well as ceramide and phosphatidylcholine levels between patients with PAD and CAD. In contrast, basic lipid markers including total cholesterol, LDL cholesterol, HDL cholesterol, lipoprotein(a) or detailed lipoprotein profiles did not differ significantly between patients with PAD and CAD. Applying ratios and scores derived from ceramides and phosphatidylcholines further improved the discrimination between PAD and CAD. These significant differences were independent of body composition, from the status of smoking or type 2 diabetes mellitus, and also from apolipoprotein C-III and other inflammatory parameters which were different between CAD and PAD.

CONCLUSION

The present study clearly suggests that PAD and CAD differ in terms of their ceramide- and phosphatidylcholine-based lipid patterns but not in lipoprotein characteristics.

Value of total cholesterol readings earlier versus later in life to predict cardiovascular risk

BACKGROUND

Prognostic implications of blood cholesterol may differ at different stages of life. This cohort study compares the value of total cholesterol (TC) readings earlier versus later in life for the prediction of coronary atherosclerosis, cardiovascular events, and cardiovascular death.

METHODS

In a cardiovascular observation study (CVOS) we performed coronary angiography and prospectively recorded cardiovascular events in 1090 patients over up to 19 years. These patients had participated in a health survey (HS) 15 years prior to the CVOS baseline. TC was measured twice, first at the earlier HS and then later at CVOS recruiting.

FINDINGS

Patients in the highest versus the lowest TC-category of the HS had an OR of 4.30 [2.41-7.65] for significant CAD at angiography, a HR of 1.74 [1.10-2.76] for cardiovascular events, and a HR of 7.55 [1.05-54.49] for cardiovascular death after multivariate adjustment. In contrast, TC as measured at the baseline of the CVOS was neither significantly associated with significant CAD (OR= 0.75 [0.49-1.13]) nor with cardiovascular events or death during follow-up (HR= 0.86 [0.62-1.18] and 0.79 [0.41-1.53], respectively). Moreover, the ESC/EAS-SCORE was found to be more powerful in predicting cardiovascular mortality when using earlier instead of later TC, with a continuous net reclassification improvement of 0.301 (p<0.001).

INTERPRETATION

Early measurement not only enables early intervention in keeping with the concept of lifelong exposure to atherogenic lipoproteins. These data also suggest that cardiovascular risk prediction is more accurate if using earlier in life TC readings.

FUNDING

The present study did not receive any particular funding.

Efficient protection of microorganisms for delivery to the intestinal tract by cellulose sulphate encapsulation

BACKGROUND

Gut microbiota in humans and animals play an important role in health, aiding in digestion, regulation of the immune system and protection against pathogens. Changes or imbalances in the gut microbiota (dysbiosis) have been linked to a variety of local and systemic diseases, and there is growing evidence that restoring the balance of the microbiota by delivery of probiotic microorganisms can improve health. However, orally delivered probiotic microorganisms must survive transit through lethal highly acid conditions of the stomach and bile salts in the small intestine. Current methods to protect probiotic microorganisms are still not effective enough.

RESULTS

We have developed a cell encapsulation technology based on the natural polymer, cellulose sulphate (CS), that protects members of the microbiota from stomach acid and bile. Here we show that six commonly used probiotic strains (5 bacteria and 1 yeast) can be encapsulated within CS microspheres. These encapsulated strains survive low pH in vitro for at least 4 h without appreciable loss in viability as compared to their respective non-encapsulated counterparts. They also survive subsequent exposure to bile. The CS microspheres can be digested by cellulase at concentrations found in the human intestine, indicating one mechanism of release. Studies in mice that were fed CS encapsulated autofluorescing, commensal E. coli demonstrated release and colonization of the intestinal tract.

CONCLUSION

Taken together, the data suggests that CS microencapsulation can protect bacteria and yeasts from viability losses due to stomach acid, allowing the use of lower oral doses of probiotics and microbiota, whilst ensuring good intestinal delivery and release.

Serum Parathyroid Hormone Predicts Mortality in Coronary Angiography Patients with Type 2 Diabetes

BACKGROUND

Elevated serum levels of parathyroid hormone (PTH), one of the main regulators of calcium homeostasis and vitamin D metabolism, have been proposed as predictors of mortality. The impact of type 2 diabetes mellitus (T2DM) on the putative association between PTH and mortality has not been investigated thus far.

AIM

The aim of our study was to investigate the impact of T2DM on the power of PTH to predict mortality risk.

METHODS

Serum PTH levels were determined in 904 consecutive Caucasian patients referred to coronary angiography for the evaluation of established or suspected stable coronary artery disease (CAD), including 235 patients with T2DM. Prospectively, deaths were recorded over a mean follow-up period of 6.3 years.

RESULTS

PTH at baseline did not differ significantly between patients with and without T2DM (P = .307). Cox regression analysis revealed that the serum PTH level strongly predicted all-cause mortality in patients with T2DM (hazard ratio [HR] = 2.35 [1.37-4.03]; P = .002), whereas PTH did not predict all-cause mortality in patients without T2DM (HR = 1.04 [0.81-1.32]; P = .766). The interaction term PTH × T2DM was significant (P = .006), indicating a significantly stronger impact of PTH on mortality risk in patients with T2DM than in individuals without diabetes. The impact of PTH on mortality risk in patients with T2DM remained significant after adjustment for glycated hemoglobin A1c, diabetes duration, classical cardiovascular risk factors, serum levels of vitamin D, and kidney function (HR = 2.10 [1.10-4.10]; P = .030).

CONCLUSION

We conclude that PTH is a significantly stronger predictor of all-cause mortality in patients with T2DM than in those without T2DM.

Data on the association between CTRP1 and future major adverse cardiovascular events in patients undergoing coronary angiography

This article provides additional data on the association of the new adipokine CTRP1 with the incidence of future major adverse cardiovascular events in a prospective cohort of patients undergoing coronary angiography. In this regard, multivariable Cox proportional hazards models taking into account cardiac risk markers are presented. Additionally, data on the impact of baseline variables including metabolic traits and co-morbidities on the incidence of future major adverse cardiovascular events are shown. This data article is associated to the research article titled ‘The Novel Adipokine CTRP1 is Significantly Associated with the Incidence of Major Adverse Cardiovascular Events’ Muendlein et al., 2019.

Quantification and characterization of autotransduction in retroviral vector producer cells

Gene therapy has evolved into a tempting strategy for the management of cancer and other life-threatening diseases. Various approaches employ retroviral vectors to deliver the therapeutic gene. The profound knowledge about retrovirus biology allows the generation of increasingly advanced vector systems as well as an accurate assessment and management of potential safety risks. This study focuses on the genetic stability of retrovirus producer cells as a basic safety requirement and its compromise by autotransduction. It has been shown previously that protection of retroviral packaging systems by superinfection interference is not guaranteed. The current study provides insight into the extent of autotransduction and the time point at which it occurs, and examines strategies to antagonize it. Therefore, a reconstituting vector system was used that obviates transgene expression in virus producer cells by physically separating transgene and promoter. Just on infection two functional expression cassettes are reconstituted, causing highly efficient transgene expression in transduced cells. Equipped with an enhanced green fluorescent protein-encoding gene, this vector allowed accurate quantification of autotransduced cells, which were then isolated by fluorescence-activated cell sorting and further characterized. Sequencing of recloned integrated vector copies demonstrated that high transgene expression levels were strictly associated with the presence of reverse-transcribed vector copies. Envelope protein expression levels, however, were found to be equal in autotransduced and noninfected virus producer cells. Finally, the occurrence of autotransduction could be assigned to an early time point after transfection and was successfully blocked by azidothymidine treatment, yielding a stable and homogeneous population of noninfected retrovirus producer cells.

Reconstituting retroviral (ReCon) vectors facilitating delivery of cytotoxic genes in cancer gene therapy approaches

BACKGROUND

We have previously described the generation of reconstituting retroviral (ReCon) vectors designed for cancer gene therapy using cytotoxic gene products. The unique vector structure with a promoter physically separated from the transgene allows generation of stable virus producer cells irrespective of the toxic gene. The mechanism of synthesis of DNA from retroviral RNA dictates that infection leads to the reconstitution of functional expression cassettes in the target cell.

METHODS

To improve vector titres, a cytomegalovirus enhancer was inserted upstream of the 5'-long-terminal repeat (LTR); the Woodchuck hepatitis virus post-transcriptional regulatory element and an elongated attachment site upstream of the 3'-LTR were included. In addition, a bacterial origin of replication was deleted and a functional internal polyadenylation signal mutated. Transcriptional targeting was attempted by introducing mammary tissue-specific promoters such as the U3 region of mouse mammary tumour virus or the promoter of the whey acidic protein encoding gene. All modifications were analysed in detail with respect to virus production and infectivity. Finally, the vector was armed with the lambda-holin encoding gene and transduced cells were analysed for cytotoxic effects.

RESULTS

Distinct modifications of the vector resulted in a titre improvement of more than 560-fold. Compatibility of the optimized vector with targeted cellular promoters was demonstrated. When equipped with the cytotoxic gene, stable producer cells could be successfully established and high titre virus infection resulted in rigorous target cell killing.

CONCLUSIONS

The ReCon vector in its optimized form is an attractive tool for cancer gene therapy approaches.

An inhibitor-resistant histone deacetylase in the plant pathogenic fungus Cochliobolus carbonum

We have partially purified and characterized histone deacetylases of the plant pathogenic fungus Cochliobolus carbonum. Depending on growth conditions, this fungus produces HC-toxin, a specific histone deacetylase inhibitor. Purified enzymes were analyzed by immunoblotting, by immunoprecipitation, and for toxin sensitivity. The results demonstrate the existence of at least two distinct histone deacetylase activities. A high molecular weight complex (430,000) is sensitive to HC-toxin and trichostatin A and shows immunoreactivity with an antibody against Cochliobolus HDC2, an enzyme homologous to yeast RPD3. The second activity, a 60,000 molecular weight protein, which is resistant even to high concentrations of well-known deacetylase inhibitors, such as HC-toxin and trichostatin A, is not recognized by antibodies against Cochliobolus HDC1 (homologous to yeast HOS2) or HDC2 and represents a different and/or modified histone deacetylase which is enzymatically active in its monomeric form. This enzyme activity is not present in the related filamentous fungus Aspergillus nidulans. Furthermore, in vivo treatment of Cochliobolus mycelia with trichostatin A and analysis of HDACs during the transition from non-toxin-producing to toxin-producing stages support an HC-toxin-dependent enzyme activity profile.

Characterization of two putative histone deacetylase genes from Aspergillus nidulans

In eukaryotic organisms, acetylation of core histones plays a key role in the regulation of transcription. Multiple histone acetyltransferases (HATs) and histone deacetylases (HDACs) maintain a dynamic equilibrium of histone acetylation. The latter form a highly conserved protein family in many eukaryotic species. In this paper, we report the cloning and sequencing of two putative histone deacetylase genes (rpdA, hosA) of Aspergillus nidulans, which are the first to be analyzed from filamentous fungi. Hybridization with a chromosome-specific cosmid library of A. nidulans allowed the localization of rpdA to chromosome III and hosA to chromosome II, respectively. PCR analyses and Southern hybridization experiments revealed that no further members of the RPD3 family are present in the genome of the fungus. Although sequence alignment displays significant amino acid similarity to other eukaryotic RPD3-type deacetylases, the deduced RPDA sequence reveals an unusual 200-amino acid extension at the C-terminus. Expression of both genes was determined by RNA blot analysis. Treatment of the cells with trichostatin A (TSA), a potent inhibitor of HDACs, was found to stimulate expression of rpdA of A. nidulans.