Integrative Proteomic and Metabolomic Analysis Reveals Metabolic Phenotype in Mice With Cardiac-Specific Deletion of Natriuretic Peptide Receptor A.

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are important biological markers and cardiac function regulators. Natriuretic peptide receptor A (NPRA) binds to an ANP or BNP ligand and induces transmembrane signal transduction by elevating the intracellular cyclic guanosine monophosphate (cGMP) levels. However, the metabolic phenotype and related mechanisms induced by NPRA deletion remain ambiguous. Here, we constructed myocardial-specific NPRA deletion mice and detected the heart functional and morphological characteristics by histological analysis and explored the altered metabolic pattern and the expression patterns of proteins by liquid chromatography-mass spectrometry (LC-MS)-based omics technology. NPRA deficiency unexpectedly did not result in significant cardiac remodeling or dysfunction. However, compared with the matched littermates, NPRA-deficient mice had significant metabolic differences. Metabolomic analysis showed that the metabolite levels varied in cardiac tissues and plasma. In total, 33 metabolites were identified in cardiac tissues and 54 were identified in plasma. Compared with control mice, NPRA-deficient mice had 20 upregulated and six downregulated metabolites in cardiac tissues and 25 upregulated and 23 downregulated metabolites in plasma. Together, NPRA deficiency resulted in increased nucleotide biosynthesis and histidine metabolism only in heart tissues and decreased creatine metabolism only in plasma. Further proteomic analysis identified 136 differentially abundant proteins in cardiac tissues, including 54 proteins with higher abundance and 82 proteins with lower abundance. Among them, cytochrome c oxidase subunit 7c and 7b (Cox7c, Cox7b), ATP synthase, H+ transporting, mitochondrial Fo complex subunit F2 (ATP5J2), ubiquinol-cytochrome c reductase, complex III subunit X (Uqcr10), and myosin heavy chain 7 (Myh7) were mainly involved in related metabolic pathways. These results revealed the essential role of NPRA in metabolic profiles and may elucidate new underlying pathophysiological mechanisms of NPRA in cardiovascular diseases.

LRP1-mediated pH-sensitive polymersomes facilitate combination therapy of glioblastoma in vitro and in vivo.

BACKGROUND: Glioblastoma (GBM) is the most invasive primary intracranial tumor, and its effective treatment is one of the most daunting challenges in oncology. The blood-brain barrier (BBB) is the main obstacle that prevents the delivery of potentially active therapeutic compounds. In this study, a new type of pH-sensitive polymersomes has been designed for glioblastoma therapy to achieve a combination of radiotherapy and chemotherapy for U87-MG human glioblastoma xenografts in nude mice and significantly increased survival time. RESULTS: The Au-DOX@PO-ANG has a good ability to cross the blood-brain barrier and target tumors. This delivery system has pH-sensitivity and the ability to respond to the tumor microenvironment. Gold nanoparticles and doxorubicin are designed as a complex drug. This type of complex drug improve the radiotherapy (RT) effect of glioblastoma. The mice treated with Au-DOX@PO-ANG NPs have a significant reduction in tumor volume. CONCLUSION: In summary, a new pH-sensitive drug delivery system was fabricated for the treatment of glioblastoma. The new BBB-traversing drug delivery system potentially represents a novel approach to improve the effects of the treatment of intracranial tumors and provides hope for glioblastoma treatment.

Chitosan oligosaccharide decorated liposomes combined with TH302 for photodynamic therapy in triple negative breast cancer.

BACKGROUND: Triple negative breast cancer (TNBC) is an aggressive tumor with extremely high mortality that results from its lack of effective therapeutic targets. As an adhesion molecule related to tumorigenesis and tumor metastasis, cluster of differentiation-44 (also known as CD44) is overexpressed in TNBC. Moreover, CD44 can be effectively targeted by a specific hyaluronic acid analog, namely, chitosan oligosaccharide (CO). In this study, a CO-coated liposome was designed, with Photochlor (HPPH) as the 660 nm light mediated photosensitizer and evofosfamide (also known as TH302) as the hypoxia-activated prodrug. The obtained liposomes can help diagnose TNBC by fluorescence imaging and produce antitumor therapy by synergetic photodynamic therapy (PDT) and chemotherapy. RESULTS: Compared with the nontargeted liposomes, the targeted liposomes exhibited good biocompatibility and targeting capability in vitro; in vivo, the targeted liposomes exhibited much better fluorescence imaging capability. Additionally, liposomes loaded with HPPH and TH302 showed significantly better antitumor effects than the other monotherapy groups both in vitro and in vivo. CONCLUSION: The impressive synergistic antitumor effects, together with the superior fluorescence imaging capability, good biocompatibility and minor side effects confers the liposomes with potential for future translational research in the diagnosis and CD44-overexpressing cancer therapy, especially TNBC.

Understanding the lived experiences of medical learners in a narrative medicine course: a phenomenological study.

BACKGROUND: Reflection and various approaches to foster reflection have been regarded as an indispensable element in enhancing professional practice across different disciplines. With its inherent potential to engage learners in reflection and improvement, narrative medicine has been adopted in various settings. However, the relevance and effectiveness of reflection remains underexplored in the context of narrative medicine, specifically in regard to the concern about variability of learner acceptance and the way learners really make sense of these reflective activities. This study aimed to explore what medical learners experience through narrative medicine and the meanings they ascribe to the phenomenon of this narrative-based learning. METHODS: Using a transcendental phenomenology approach, twenty medical learners were interviewed about their lived experiences of taking a narrative medicine course during their internal medicine clerkship rotation. Moustakas' phenomenological analysis procedures were applied to review the interview data. RESULTS: Six themes were identified: feeling hesitation, seeking guidance, shifting roles in narratives, questioning relationships, experiencing transformation, and requesting a safe learning environment. These themes shaped the essence of the phenomenon and illustrated what and how medical learners set out on a reflective journey in narrative medicine. These findings elucidate fundamental elements for educators to consider how narrative approaches can be effectively used to engage learners in reflective learning and practice. CONCLUSION: Adopting Moustakas' transcendental phenomenology approach, a better understanding about the lived experiences of medical learners regarding learning in narrative medicine was identified. Learner hesitancy should be tackled with care by educators so as to support learners with strategies that address guidance, relationship, and learning environment. In so doing, medical learners can be facilitated to develop reflective capabilities for professional and personal growth.

Design Features for Improving Mobile Health Intervention User Engagement: Systematic Review and Thematic Analysis.

BACKGROUND: Well-designed mobile health (mHealth) interventions support a positive user experience; however, a high rate of disengagement has been reported as a common concern regarding mHealth interventions. To address this issue, it is necessary to summarize the design features that improve user engagement based on research over the past 10 years, during which time the popularity of mHealth interventions has rapidly increased due to the use of smartphones. OBJECTIVE: The aim of this review was to answer the question "Which design features improve user engagement with mHealth interventions?" by summarizing published literature with the purpose of guiding the design of future mHealth interventions. METHODS: This review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist. Databases, namely, PubMed, Web of Science, Cochrane Library, Ovid EMBASE, and Ovid PsycINFO, were searched for English and Chinese language papers published from January 2009 to June 2019. Thematic analysis was undertaken to assess the design features in eligible studies. The Mixed Methods Appraisal Tool was used to assess study quality. RESULTS: A total of 35 articles were included. The investigated mHealth interventions were mainly used in unhealthy lifestyle (n=17) and chronic disease (n=10) prevention programs. Mobile phone apps (n=24) were the most common delivery method. Qualitative (n=22) and mixed methods (n=9) designs were widely represented. We identified the following 7 themes that influenced user engagement: personalization (n=29), reinforcement (n=23), communication (n=20), navigation (n=17), credibility (n=16), message presentation (n=16), and interface aesthetics (n=7). A checklist was developed that contained these 7 design features and 29 corresponding specific implementations derived from the studies. CONCLUSIONS: This systematic review and thematic synthesis identified useful design features that make an mHealth intervention more user friendly. We generated a checklist with evidence-based items to enable developers to use our findings easily. Future evaluations should use more robust quantitative approaches to elucidate the relationships between design features and user engagement.

Production of trehalose with trehalose synthase expressed and displayed on the surface of Bacillus subtilis spores.

BACKGROUND: Bacillus subtilis spores have been commonly used for the surface display of various food-related or human antigens or enzymes. For successful display, the target protein needs to be fused with an anchor protein. The preferred anchored proteins are the outer-coat proteins of spores; outer-coat proteins G (CotG) and C (CotC) are commonly used. In this study, mutant trehalose synthase (V407M/K490L/R680E TreS) was displayed on the surface of B. subtilis WB800n spores using CotG and CotC individually or in combination as an anchoring protein. RESULTS: Western blotting, immunofluorescence, dot blot, and enzymatic-activity assays detected TreS on the spore surface. The TreS activity with CotC and CotG together as the anchor protein was greater than the sum of the enzymatic activities with CotC or CotG alone. The TreS displayed on the spore surface with CotC and CotG together as the anchoring protein showed elevated and stable specific activity. To ensure spore stability and prevent spore germination in the trehalose preparation system, two germination-specific lytic genes, sleB and cwlJ, were deleted from the B. subtilis WB800n genome. It was demonstrated that this deletion did not affect the growth and spore formation of B. subtilis WB800n but strongly inhibited germination of the spores during transformation. The conversion rate of trehalose from 300 g/L maltose by B. subtilis strain WB800n(ΔsleB, ΔcwlJ)/cotC-treS-cotG-treS was 74.1% at 12 h (350 U/[g maltose]), and its enzymatic activity was largely retained, with a conversion rate of 73% after four cycles. CONCLUSIONS: The spore surface display system based on food-grade B. subtilis with CotC and CotG as a combined carrier appears to be a powerful technology for TreS expression, which may be used for the biotransformation of D-maltose into D-trehalose.

Design and Development of Lidocaine Microemulsions for Transdermal Delivery.

Topical administration is a preferable choice for local anesthetic delivery. Microemulsions have shown great effectiveness for transdermal transport of lidocaine. However, fabrication of microemulsions containing highly concentrated lidocaine (10%) to provide an extended local anesthetic effect is still a challenge. This study investigated the feasibility of using microemulsions for transdermal delivery of a high dosage of lidocaine (10%). At first, eutectic mixtures by kneading lidocaine with thymol were tailored to form a lipophilic solution, then the mixtures were readily incorporated into the oil phase of microemulsions after addition of proper surfactants and cosurfactants. The physicochemical properties, the skin permeation, local anesthetic efficacy, and the irritation experiment of the developed microemulsions were evaluated. The optimum composition was as follows: 12% of ethyl oleate as oil phase, 28% of the mixed surfactant, and cosurfactant (polyoxyl 15 hydroxystearate and ethanol) and 60% of the aqueous phase. The average particle size was about 13 nm. The transmission electron microscope (TEM) studies revealed almost homogeneous spherical globules without aggregation. The Fourier-transform infrared spectroscopy (FTIR) results highlighted the drugs homogeneously dispersed in the microemulsions. In vitro skin permeation and in vivo anesthesia effect evaluation indicated that microemulsions can enhance and extend the anesthetic effect of lidocaine. The irritable results indicated that the microemulsions had the better biocompatibility and the negligible influence on the dermal. Therefore, incorporating the eutectic mixtures into microemulsions could be proposed as an attractive choice and a promising transdermal delivery strategy for the future topical anesthetic therapy.

Facile assembly of upconversion nanoparticle-based micelles for active targeted dual-mode imaging in pancreatic cancer.

BACKGROUND: Pancreatic cancer remains the leading cause of cancer-related deaths, the existence of cancer stem cells and lack of highly efficient early detection may account for the poor survival rate. Gadolinium ion-doped upconversion nanoparticles (UCNPs) provide opportunities for combining fluorescent with magnetic resonance imaging, and they can improve the diagnostic efficacy of early pancreatic cancer. In addition, as one transmembrane glycoprotein overexpressed on the pancreatic cancer stem cells, CD326 may act as a promising target. In this study, we developed a facile strategy for developing anti-human CD326-grafted UCNPs-based micelles and performed the corresponding characterizations. After conducting in vitro and vivo toxicology experiments, we also examined the active targeting capability of the micelles upon dual-mode imaging in vivo. RESULTS: We found that the micelles owned superior imaging properties and long-time stability based on multiple characterizations. By performing in vitro and vivo toxicology assay, the micelles had good biocompatibility. We observed more cellular uptake of the micelles with the help of anti-human CD326 grafted onto the micelles. Furthermore, we successfully concluded that CD326-conjugated micelles endowed promising active targeting ability by conducting dual-mode imaging in human pancreatic cancer xenograft mouse model. CONCLUSIONS: With good biocompatibility and excellent imaging properties of the micelles, our results uncover efficient active homing of those micelles after intravenous injection, and undoubtedly demonstrate the as-obtained micelles holds great potential for early pancreatic cancer diagnosis in the future and would pave the way for the following biomedical applications.

Novel trigenic CACNA1C/DES/MYPN mutations in a family of hypertrophic cardiomyopathy with early repolarization and short QT syndrome.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) patients with early repolarization (ER) pattern are at higher risk of ventricular arrhythmia, yet the genetic background of this situation has not been well investigated. Here we report novel trigenic mutations detected in a Chinese family of obstructive HCM with ER and short QT syndrome (SQTS). METHODS: Proband and family members underwent detailed medical assessments. DNAs were extracted from peripheral blood leukocytes for genetic screening with next generation method. The functional characterization of the mutation was conducted in TSA201 cells with patch-clamp experiment. RESULTS: The proband was a 52-year-old male who had a ER pattern ECG in inferioral-lateral leads with atrioventricular block and QTc of 356 ms. He also suffered from severe left ventricular hypertrophy and dysfunction. Targeted sequencing revealed trigenic mutations: c.700G>A/p.E234K in DES, c.2966G>A/p.R989H in MYPN, and c.5918G>C/p.R1973P in CACNA1C. All mutations were also detected in his daughter with ER and mild myocardium hypertrophy. The CACNA1C-R1973P mutation caused significant reduction (68.4%) of ICa compared to CACNA1C-WT (n = 14 and 14, P < 0.05). The computer modeling showed that all 3 mutations were highly disease-causing. The proband received the CRT-D (cardiac resynchronizing therapy) implantation, which lowered the left ventricular outflow tract gradient (LVOTG, 124 mmHg pre vs. 27 mmHg post) and restored the LV function (LVEF 40% pre vs. 63% post). CONCLUSIONS: The study reveals a novel CACNA1C mutation underlying the unique ER pattern ECGs with SQTS. It also shows the rare trigenic mutations are the pathogenic substrates for the complicated clinical manifestation in HCM patients.

Antioxidant catalase rescues against high fat diet-induced cardiac dysfunction via an IKKß-AMPK-dependent regulation of autophagy.

Autophagy, a conservative degradation process for long-lived and damaged proteins, participates in a variety of biological processes including obesity. However, the precise mechanism of action behind obesity-induced changes in autophagy still remains elusive. This study was designed to examine the role of the antioxidant catalase in high fat diet-induced changes in cardiac geometry and function as well as the underlying mechanism of action involved with a focus on autophagy. Wild-type (WT) and transgenic mice with cardiac overexpression of catalase were fed low or high fat diet for 20 weeks prior to assessment of myocardial geometry and function. High fat diet intake triggered obesity, hyperinsulinemia, and hypertriglyceridemia, the effects of which were unaffected by catalase transgene. Myocardial geometry and function were compromised with fat diet intake as manifested by cardiac hypertrophy, enlarged left ventricular end systolic and diastolic diameters, fractional shortening, cardiomyocyte contractile capacity and intracellular Ca²âº mishandling, the effects of which were ameliorated by catalase. High fat diet intake promoted reactive oxygen species production and suppressed autophagy in the heart, the effects of which were attenuated by catalase. High fat diet intake dampened phosphorylation of inhibitor kappa B kinase ß(IKKß), AMP-activated protein kinase (AMPK) and tuberous sclerosis 2 (TSC2) while promoting phosphorylation of mTOR, the effects of which were ablated by catalase. In vitro study revealed that palmitic acid compromised cardiomyocyte autophagy and contractile function in a manner reminiscent of fat diet intake, the effect of which was significantly alleviated by inhibition of IKKß, activation of AMPK and induction of autophagy. Taken together, our data revealed that the antioxidant catalase counteracts against high fat diet-induced cardiac geometric and functional anomalies possibly via an IKKß-AMPK-dependent restoration of myocardial autophagy. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases.

Spatiotemporal Regulation and Transport Engineering for Sustainable Production of Geraniol in Candida glycerinogenes.

Geraniol is an attractive natural monoterpene with significant industrial and commercial value in the fields of pharmaceuticals, condiments, cosmetics, and bioenergy. The biosynthesis of monoterpenes suffers from the availability of key intermediates and enzyme-to-substrate accessibility. Here, we addressed these challenges in Candida glycerinogenes by a plasma membrane-anchoring strategy and achieved sustainable biosynthesis of geraniol using bagasse hydrolysate as substrate. On this basis, a remarkable 2.4-fold improvement in geraniol titer was achieved by combining spatial and temporal modulation strategies. In addition, enhanced geraniol transport and modulation of membrane lipid-associated metabolism effectively promoted the exocytosis of toxic monoterpenes, significantly improved the resistance of the engineered strain to monoterpenes and improved the growth of the strains, resulting in geraniol yield up to 1207.4 mg L-1 at shake flask level. Finally, 1835.2 mg L-1 geraniol was obtained in a 5 L bioreactor using undetoxified bagasse hydrolysate. Overall, our study has provided valuable insights into the plasma membrane engineering of C. glycerinogenes for the sustainable and green production of valuable compounds.

Development of a co-culture system for green production of caffeic acid from sugarcane bagasse hydrolysate.

Caffeic acid (CA) is a phenolic acid compound widely used in pharmaceutical and food applications. However, the efficient synthesis of CA is usually limited by the resources of individual microbial platforms. Here, a cross-kingdom microbial consortium was developed to synthesize CA from sugarcane bagasse hydrolysate using Escherichia coli and Candida glycerinogenes as chassis. In the upstream E. coli module, shikimate accumulation was improved by intensifying the shikimate synthesis pathway and blocking shikimate metabolism to provide precursors for the downstream CA synthesis module. In the downstream C. glycerinogenes module, conversion of p-coumaric acid to CA was improved by increasing the supply of the cytoplasmic cofactor FAD(H2). Further, overexpression of ABC transporter-related genes promoted efflux of CA and enhanced strain resistance to CA, significantly increasing CA titer from 103.8 mg/L to 346.5 mg/L. Subsequently, optimization of the inoculation ratio of strains SA-Ec4 and CA-Cg27 in this cross-kingdom microbial consortium resulted in an increase in CA titer to 871.9 mg/L, which was 151.6% higher compared to the monoculture strain CA-Cg27. Ultimately, 2311.6 and 1943.2 mg/L of CA were obtained by optimization of the co-culture system in a 5 L bioreactor using mixed sugar and sugarcane bagasse hydrolysate, respectively, with 17.2-fold and 14.6-fold enhancement compared to the starting strain. The cross-kingdom microbial consortium developed in this study provides a reference for the production of other aromatic compounds from inexpensive raw materials.

Cross-linked α-Ni(OH)2 nanosheets with a Ni3+-rich structure for accelerating electrochemical oxidation of 5-hydroxymethylfurfural.

Electrochemical oxidation of biomass-based 5-hydroxymethylfurfural (HMF) is an effective approach for achieving the high-value products of 2,5-furandicarboxylic acid (FDCA). However, the restricted formation of high-valence metal active species for electrocatalysts results in a sluggish kinetic process of HMF oxidation reaction (HMFOR). Herein, we fabricated the Ni3+-rich cross-linked α-Ni(OH)2 nanosheets for accelerating the HMFOR through an anion-mediated strategy. It is identified that the Cl- ions with strong penetrability replace a portion of lattice oxygen atoms in α-Ni(OH)2 to form Ni-Cl bonds, contributing to breaking the inherent lattice order and generating a special Ni3+-rich structure. Owing to the promoted adsorption and accelerated oxidation of hydroxyl and aldehyde groups by the affluent Ni3+ active species, the large oxidation current density of 116.5 mA cm-2 and HMFOR kinetic constant of 0.067 min-1 has been achieved at 1.45 V (vs. RHE). By analyzing the oxidation products, the FDCA yield and Faradic efficiency are both higher than 99.25 % and 99.36 % for five successive determinations. Therefore, this work provides an insightful anion-mediated strategy for designing high-performance electrocatalysts for biomass conversion application.

To master or perform? Exploring relations between achievement goals and conceptual change learning.

BACKGROUND: Research is needed to explore conceptual change in relation to achievement goal orientations and depth of processing. AIMS: To address this need, we examined relations between achievement goals, use of deep versus shallow processing strategies, and conceptual change learning using a think-aloud protocol. SAMPLE AND METHOD: Seventy-three undergraduate students were assessed on their prior knowledge and misconceptions about Newtonian mechanics, and then reported their achievement goals and participated in think-aloud protocols while reading Newtonian physics texts. RESULTS: A mastery-approach goal orientation positively predicted deep processing strategies, shallow processing strategies, and conceptual change. In contrast, a performance-approach goal orientation did not predict either of the processing strategies, but negatively predicted conceptual change. A performance-avoidance goal orientation negatively predicted deep processing strategies and conceptual change. Moreover, deep and shallow processing strategies positively predicted conceptual change as well as recall. Finally, both deep and shallow processing strategies mediated relations between mastery-approach goals and conceptual change. CONCLUSION: Results provide some support for Dole and Sinatra's (1998) Cognitive Reconstruction of Knowledge Model of conceptual change but also challenge specific facets with regard to the role of depth of processing in conceptual change.

Metabolic Engineering of Candida glycerinogenes for Sustainable Production of Geraniol.

Geraniol is a class of natural products that are widely used in the aroma industry due to their unique aroma. Here, to achieve the synthesis of geraniol and alleviate the intense competition from the yeast ergosterol pathway, a transcription factor-mediated ergosterol feedback system was developed in this study to autonomously regulate ergosterol metabolism and redirect carbon flux to geraniol synthesis. In addition, the modification of ergosterol-responsive promoters, the optimization of transcription factor expression intensity, and stepwise metabolic engineering resulted in a geraniol titer of 531.7 mg L-1. For sustainable production of geraniol, we constructed a xylose assimilation pathway in Candida glycerinogenes (C. glycerinogenes). Then, the xylose metabolic capacity was ameliorated and the growth of the engineered strain was rescued by activating the pentose phosphate (PP) pathway. Finally, we obtained 1091.6, 862.4, and 921.8 mg L-1 of geraniol in a 5 L bioreactor by using pure glucose, simulated wheat straw hydrolysates, and simulated sugarcane bagasse hydrolysates, with yields of 47.5, 57.9, and 59.1 mg g-1 DCW, respectively. Our study demonstrated that C. glycerinogenes has the potential to produce geraniol from lignocellulosic biomass, providing a powerful tool for the sustainable synthesis of other valuable monoterpenes.

Effect of the index of cardiac electrophysiological balance on major adverse cardiovascular events in patients with diabetes complicated with coronary heart disease.

Purpose: To investigate the prognostic value of the index of cardio-electrophysiological balance (ICEB) and its association with major adverse cardiac events (MACE) and cardiovascular death in diabetic patients complicated with coronary heart disease. Methods: A total of 920 diabetic patients were enrolled in this longitudinal study. Participants were categorized into three groups based on their ICEB levels: normal ICEB, low ICEB, and high ICEB. The primary outcome was the occurrence of MACE, and secondary outcomes included cardiovascular death, coronary heart disease (CHD), heart failure (HF), and sudden cardiac arrest (SCA). Patients were followed for a median period of 3.26 years, and the associations between ICEB levels and various outcomes were evaluated. Results: Over the follow-up period, 46 (5.0%) MACE were observed in the normal ICEB group, 57 (6.2%) in the low ICEB group, and 62 (6.8%) in the high ICEB group. Elevated ICEB levels were found to be associated with a higher risk of MACE and cardiovascular death. A significant relationship between ICEB levels and the risk of MACE was observed for both genders. The risk of MACE increased with each unit increment in the ICEB index. However, the two-stage linear regression model did not outperform the single-line linear regression models in determining the threshold effect. Conclusion: This study demonstrates the potential utility of ICEB, derived from a standard non-invasive ECG, as a prognostic tool for predicting MACE and cardiovascular death in diabetic patients complicated with CVD. The associations between ICEB levels and the risk of MACE highlight the importance of understanding cardiac electrophysiological imbalances and their implications in CVD.

Balancing Pyruvate Node Based on a Dual-Layered Dynamic Regulation System to Improve the Biosynthesis of Caffeic Acid in Candida glycerinogenes.

Caffeic acid is a phenolic acid compound widely applied in the food and pharmaceutical fields. Currently, one of the reasons for the low yield of caffeic acid biosynthesis is that the carbon flow enters mainly into the TCA cycle via pyruvate, which leads to low concentrations of erythrose 4-phosphate (E4P) and phosphoenolpyruvate (PEP), the precursors of caffeic acid synthesis. Here, we developed a growth-coupled dual-layered dynamic regulation system. This system controls intracellular pyruvate supply in real time by responding to intracellular pyruvate and p-coumaric acid concentrations, autonomously coordinates pathway gene expression, and redirects carbon metabolism to balance cell growth and caffeic acid synthesis. Finally, our constructed engineered strain based on the dual-layered dynamic regulation system achieved a caffeic acid titer of 559.7 mg/L in a 5 L bioreactor. Thus, this study demonstrated the efficiency and potential of this system in boosting the yield of aromatic compounds.

The landscape of N6-methyladenosine modification patterns and altered transcript profiles in the cardiac-specific deletion of natriuretic peptide receptor A.

The atrial natriuretic peptide (ANP) and the brain natriuretic peptide (BNP) are critical biological makers and regulators of cardiac functions. Our previous results show that NPRA (natriuretic peptide receptor A)-deficient mice have distinct metabolic patterns and expression profiles compared with the control. Still, the molecular mechanism that could account for this observation remains to be elucidated. Here, methylation alterations were detected by mazF-digestion, and differentially expressed genes of transcriptomes were detected by a Genome Oligo Microarray using the myocardium from NPRA-deficient (NPRA-/-) mice and wild-type (NPRA+/+) mice as the control. Comprehensive analysis of m6A methylation data gave an altered landscape of m6A modification patterns and altered transcript profiles in cardiac-specific NPRA-deficient mice. The m6A "reader" igf2bp3 showed a clear trend of increase, suggesting a function in altered methylation and expression in cardiac-specific NPRA-deficient mice. Intriguingly, differentially m6A-methylated genes were enriched in the metabolic process and insulin resistance pathway, suggesting a regulatory role in cardiac metabolism of m6A modification regulated by NPRA. Notably, it was confirmed that the pyruvate dehydrogenase kinase 4 (Pdk4) gene upregulated the gene expression and the hypermethylation level simultaneously, which may be the key factor for the cardiac metabolic imbalance and insulin resistance caused by natriuretic peptide signal resistance. Taken together, cardiac metabolism might be regulated by natriuretic peptide signaling, with decreased m6A methylation and a decrease of Pdk4.

BNP protects against diabetic cardiomyopathy by promoting Opa1-mediated mitochondrial fusion via activating the PKG-STAT3 pathway.

Brain natriuretic peptide (BNP) belongs to the family of natriuretic peptides, which are responsible for a wide range of actions. Diabetic cardiomyopathy (DCM) is often associated with increased BNP levels. This present research intends to explore the role of BNP in the development of DCM and the underlying mechanisms. Diabetes was induced in mice using streptozotocin (STZ). Primary neonatal cardiomyocytes were treated with high glucose. It was found that the levels of plasma BNP started to increase at 8 weeks after diabetes, which preceded the development of DCM. Addition of exogenous BNP promoted Opa1-mediated mitochondrial fusion, inhibited mitochondrial oxidative stress, preserved mitochondrial respiratory capacity and prevented the development of DCM, while knockdown of endogenous BNP exacerbated mitochondrial dysfunction and accelerated DCM. Opa1 knockdown attenuated the aforementioned protective action of BNP both in vivo and in vitro. BNP-induced mitochondrial fusion requires the activation of STAT3, which facilitated Opa1 transcription by binding to its promoter regions. PKG, a crucial signaling biomolecule in the BNP signaling pathway, interacted with STAT3 and induced its activation. Knockdown of NPRA (the receptor of BNP) or PKG blunted the promoting effect of BNP on STAT3 phosphorylation and Opa1-mediated mitochondrial fusion. The results of this study demonstrate for the first time that there is a rise in BNP during the early stages of DCM as a compensatory protection mechanism. BNP is a novel mitochondrial fusion activator in protecting against hyperglycemia-induced mitochondrial oxidative injury and DCM through the activation of NPRA-PKG-STAT3-Opa1 signaling pathway.