Suppression of RCAN1 alleviated lipid accumulation and mitochondrial fission in diabetic cardiomyopathy.

BACKGROUND: Although metabolic disturbance is a characteristic of diabetic cardiomyopathy (DbCM), the detailed pathogenesis of DbCM remains unknown. METHODS: We used a heart transplantation (HTx) cohort to explore the effect of diabetes mellitus on heart failure (HF) progression dependent of myocardium. Microscopic and ultramicroscopic pathology were used to depict the pathological features of human myocardium of DbCM. We performed targeted metabolomics to characterize the metabolic phenotype of human DbCM. Transcriptomics data were analyzed and weighted gene co-expression network analysis was performed to explore the potential upstream regulator for metabolic remodeling of DbCM. In vivo and in vitro experiments were further conducted to demonstrate the therapeutic effects and molecular mechanisms. RESULTS: DbCM promoted the progression of HF and increased death or HF-rehospitalization after HTx. Lipid accumulation and mitochondrial fission were the obvious pathological features of DbCM myocardium. The concentrations of C14:0-CoA and C16:1-CoA were significantly increased in the myocardium, and they were positively correlated with the accelerated HF progression and RCAN1 expression in DbCM patients. Knockdown of RCAN1 improved cardiac dysfunction, lipid accumulation, and mitochondrial fission in db/db mice. In vitro studies showed that RCAN1 knockdown improved mitochondrial dysfunction in DbCM cardiomyocytes via the RCAN1-p-Drp1 Ser616 axis. CONCLUSIONS: Diabetes is associated with faster progression of HF and causes poor prognosis after HTx, accompanied by metabolic remodeling in the myocardium. Accumulation of long chain acyl-CoA in the myocardium is the metabolic hallmark of human DbCM and is associated with more rapid disease progression for DbCM patients. Upregulation of RCAN1 in the myocardium is associated with the metabolic signatures of DbCM and RCAN1 is a potential therapeutic target for DbCM.

Single-Cell RNA Sequencing of Coronary Perivascular Adipose Tissue From End-Stage Heart Failure Patients Identifies SPP1+ Macrophage Subpopulation as a Target for Alleviating Fibrosis.

BACKGROUND: Perivascular adipose tissue (PVAT) is vital for vascular homeostasis, and PVAT dysfunction is associated with increased atherosclerotic plaque burden. But the mechanisms underlining coronary PVAT dysfunction in coronary atherosclerosis remain elusive. METHODS: We performed single-cell RNA sequencing of the stromal vascular fraction of coronary PVAT from 3 groups of heart transplant recipients with end-stage heart failure, including 3 patients with nonobstructive coronary atherosclerosis, 3 patients with obstructive coronary artery atherosclerosis, and 4 nonatherosclerosis control subjects. Bioinformatics was used to annotate the cellular populations, depict the cellular developmental trajectories and interactions, and explore the differences among 3 groups of coronary PVAT at the cellular and molecular levels. Pathological staining, quantitative real-time polymerase chain reaction, and in vitro studies were performed to validate the key findings. RESULTS: Ten cell types were identified among 67 936 cells from human coronary PVAT. Several cellular subpopulations, including SPP1+ (secreted phosphoprotein 1) macrophages and profibrotic fibroadipogenic progenitor cells, were accumulated in PVAT surrounding atherosclerotic coronary arteries compared with nonatherosclerosis coronary arteries. The fibrosis percentage was increased in PVAT surrounding atherosclerotic coronary arteries, and it was positively associated with the grade of coronary artery stenosis. Cellular interaction analysis suggested OPN (osteopontin) secreted by SPP1+ macrophages interacted with CD44 (cluster of differentiation 44)/integrin on fibroadipogenic progenitor cells. Strikingly, correlation analyses uncovered that higher level of SPP1 in PVAT correlates with a more severe fibrosis degree and a higher coronary stenosis grade. In vitro studies showed that conditioned medium from atherosclerotic coronary PVAT promoted the migration and proliferation of fibroadipogenic progenitor cells, while such effect was prevented by blocking CD44 or integrin. CONCLUSIONS: SPP1+ macrophages accumulated in the PVAT surrounding atherosclerotic coronary arteries, and they promoted the migration and proliferation of fibroadipogenic progenitor cells via OPN-CD44/integrin interaction and thus aggravated the fibrosis of coronary PVAT, which was positively correlated to the coronary stenosis burden. Therefore, SPP1+ macrophages in coronary PVAT may participate in the progression of coronary atherosclerosis.

Fabrication of a novel polyurethane foam-alginate-zeolite hydrogel and subsequent KSND bacteria encapsulation: evidence of accelerated biofilm colonization and enhanced nitrogen removal efficiency.

Biofilms are used widely to remove nitrogen from wastewater; however, most biofilm carriers (i.e. polyurethane foam, PUF) are hydrophobic organic materials with millimetre-scale apertures, ineffective attachment, and unstable colonization of microorganisms. To address these limitations, hydrophilic sodium alginate (SA) mixed with zeolite powder (Zeo) was cross-linked in PUF to form a micro-scale hydrogel (PAS) with a well-organized and reticular cellular structure. Scanning electron microscopy revealed that immobilized cells were entrapped in the interior of hydrogel filaments and rapidly formed a stable biofilm on the surface. The biofilm generated was 10.3-fold greater than the film developed on PUF. Kinetics and isotherm studies revealed that the as-developed carrier, because of the presence of Zeo, effectively improved the adsorption of NH4+-N by 53%. The PAS carrier achieved total nitrogen removal in excess of 86% for low carbon-to-nitrogen ratio wastewater treated for 30 d, indicating that this novel modification-encapsulation technology has potential for wastewater treatment.

A high-yielding strain of indole-3-acetic acid isolated from food waste compost: metabolic pathways, optimization of fermentation conditions, and application.

Food waste is a potential resource to prepare microbial fertilizer. However, functional microorganisms derived from the food waste compost (FWC) are relatively lacking. We have isolated, identified, characterized and optimized a high-yielding indole-3-acetic acid (IAA) strain from FWC and further evaluated its growth promoting effect on plants. A IAA high-yielding strain, Providencia sp.Y, with an initial IAA yield of 139.98 mg L-1, was obtained through high-throughput screening, and identified by 16S rRNA gene sequence. The novel strain Y may simultaneously involve the following three pathways from L-tryptophan to IAA, which were identified using liquid chromatography-tandem mass spectrometry: (1) L-tryptophan-indole-3-ethanol-indole-3-acetaldehyde-indole-3-acetic acid; (2) L-tryptophan-1-hydroxy-indole-3-ethanol-indole-3-acetic acid; (3) L-tryptophan-indole-3-acetamide-indole-3-acetic acid. The most suitable comprehensive conditions for IAA production, which were optimized by single factor experiment, were: culture time 12 h, inoculation amount 2% (v/v), NaCl concentration 4% (w/v), culture temperature 25℃, initial pH = 5, and L-tryptophan concentration 3.0 g L-1. The yield of IAA after optimization was increased by 590.48%, from 139.98 mg L-1 (before optimization) to 966.54 mg L-1. Diluted 200-fold microbial suspension could significantly improve the growth of pakchoi seedlings. The seedling plant height, root length, leaf width, leaf length, and fresh weight with microbial suspension increased by 17.39%, 107.35%, 77.98%, 37.75%, and 215.38%, respectively, compared with those without microbial suspension. The increase was greater than that of commercial bacterial agents. In conclusion, this isolated strain can be used as an economical microbial inoculant and provides a new germplasm resource for developing microbial fertilizers.

Cellular Landscapes of Nondiseased Human Cardiac Valves From End-Stage Heart Failure-Explanted Heart.

BACKGROUND: Exploring the mechanisms of valvular heart disease at the cellular level may be useful to identify new therapeutic targets; however, the comprehensive cellular landscape of nondiseased human cardiac valve leaflets remains unclear. METHODS: The cellular landscapes of nondiseased human cardiac valve leaflets (5 aortic valves, 5 pulmonary valves, 5 tricuspid valves, and 3 mitral valves) from end-stage heart failure patients undergoing heart transplantation were explored using single-cell RNA sequencing. Bioinformatics was used to identify the cell types, describe the cell functions, and investigate cellular developmental trajectories and interactions. Differences among the 4 types of cardiac valves at the cellular level were summarized. Pathological staining was performed to validate the key findings of single-cell RNA sequencing. An integrative analysis of our single-cell data and published genome-wide association study-based and bulk RNA sequencing-based data provided insights into the cell-specific contributions to calcific aortic valve diseases. RESULTS: Six cell types were identified among 128 412 cells from nondiseased human cardiac valve leaflets. Valvular interstitial cells were the largest population, followed by myeloid cells, lymphocytes, valvular endothelial cells, mast cells, and myofibroblasts. The 4 types of cardiac valve had distinct cellular compositions. The intercellular communication analysis revealed that valvular interstitial cells were at the center of the communication network. The integrative analysis of our single-cell RNA sequencing data revealed key cellular subpopulations involved in the pathogenesis of calcific aortic valve diseases. CONCLUSIONS: The cellular landscape differed among the 4 types of nondiseased cardiac valve, which might explain their differences in susceptibility to pathological remodeling and valvular heart disease.

Enhanced nitrogen removal from low-temperature wastewater by an iterative screening of cold-tolerant denitrifying bacteria.

The biological process to remove nitrogen in winter effluent is often seriously compromised due to the effect of low temperatures (< 13 °C) on the metabolic activity of microorganisms. In this study, a novel heterotrophic nitrifying-aerobic denitrifying bacterium with cold tolerance was isolated by iterative domestication and named Moraxella sp. LT-01. The LT-01 maintained almost 60% of its maximal growth activity at 10 °C. Under initial concentrations of 100 mg/L, the removal efficiencies of ammonium, nitrate, nitrite by LT-01 were 70.3%, 65.4%, 61.7% respectively for 72 h incubation at 10 °C. Nitrogen balance analysis showed that about 46% of TN was released as gases and 16% of TN was assimilated for cell growth. The biomarker genes involved in nitrification and denitrification pathways were identified by gene-specific PCR and revealed that the LT-01 has nitrite reductase (NirS) but not hydroxylamine reductase (HAO), which implies the involvement of other genes in the process. The study indicates that LT-01 has the potential for use in low-temperature regions for efficient sewage treatment.

[Aeromonas immobilized on chitosan for treating high-oil wastewater from kitchens].

To effectively solve the serious impact of high oil in the kitchen wastewater on the downstream treatment process, an excellent oil-degrading strain Aeromonas allosaccarophila CY-01 was immobilized to prepare Chitosan-Aeromonas pellets (CH-CY01) by using chitosan as a carrier. Oil degradation condition and efficiency of CH-CY01 pellets were assessed. The growth of immobilized CH-CY01 was almost unaffected, and the maximum degradation rate of soybean oil was 89.7%. Especially at 0.5% NaCl concentration, oil degradation efficiency of CH-CY01 was increased by 20% compared with free cells. In the presence of a surfactant (sodium dodecylbenzene sulfonate) at 1 mg/L, the degradation efficiency of oil by CH-CY01 was increased by 40%. Moreover, using the high-oil catering wastewater as the substrate, more than 80% of the solid oil was degraded with 1% (V/V) CH-CY01 pellets treatment for 7 days, significantly higher than that of free cells. In summary, immobilized CH-CY01 significantly improved the efficiency of oil degradation.

Enhanced stability and nitrogen removal efficiency of Klebsiella sp. entrapped in chitosan beads applied in the domestic sewage system.

Although numerous denitrifying bacteria have been isolated and characterized, their capacity is seriously compromised by traditional inoculant addition and environmental stress in open bioreactors for wastewater treatment. In this study, a biocompatible material, chitosan, was used as a carrier to immobilize a simultaneously heterotrophic nitrifying-aerobic denitrifying bacterium Klebsiella sp., KSND, for continuous nitrogen removal from domestic wastewater in an open purification tank. The results showed that immobilization had no significant effect on cell viability and was beneficial for the reproduction and adhesion of cells. The entrapped KSND exhibited a slightly higher nitrogen removal efficiency of 90.09% than that of free KSND (87.69%). Subsequently, repeated batch cultivation experiments and analysis of the effects of organic contaminants and metal ions were performed using artificial wastewater and domestic wastewater. The findings revealed that the immobilized KSND beads presented desirable biophysical properties with good mechanical stability, cell viability, and enrichment, remarkable stability in organic contaminants and metal ions, and high efficiency nitrogen removal capacity. In conclusion, the developed immobilized denitrifying bacteria system has great potential for continuous wastewater treatment in open bioreactors.