Microbial Metabolite Dysbiosis and Colorectal Cancer

The global burden of colorectal cancer (CRC) is expected to continuously increase. Through research performed in the past decades, the effects of various environmental factors on CRC development have been well identified. Diet, the gut microbiota and their metabolites are key environmental factors that profoundly affect CRC development. Major microbial metabolites with a relevance for CRC prevention and pathogenesis include dietary fiber-derived short-chain fatty acids, bile acid derivatives, indole metabolites, polyamines, trimethylamine-N-oxide, formate, and hydrogen sulfide. These metabolites regulate various cell types in the intestine, leading to an altered intestinal barrier, immunity, chronic inflammation, and tumorigenesis. The physical, chemical, and metabolic properties of these metabolites along with their distinct functions to trigger host receptors appear to largely determine their effects in regulating CRC development. In this review, we will discuss the current advances in our understanding of the major CRC-regulating microbial metabolites, focusing on their production and interactive effects on immune responses and tumorigenesis in the colon.

Arabidopsis CK2 family gene CKB3 involved in abscisic acid signaling / Gene da família Arabidopsis CK2 CKB3 envolvido na sinalização de ácido abscísico

CKB3 is a regulatory (beta) subunit of CK2. In this study Arabidopsis thaliana homozygous T-DNA mutant ckb3 was studied to understand the role of CKB3 in abscisic acid (ABA) signaling. The results shown: CKB3 was expressed in all organs and the highest expression in the seeds, followed by the root. During seed germination and root growth the ckb3 mutant showed reduced sensitivity to ABA. The ckb3 mutant had more stomatal opening and increased proline accumulation and leaf water loss. The expression levels of number of genes in the ABA regulatory network had changed. This study demonstrates that CKB3 is an ABA signaling-related gene and may play a positive role in ABA signaling.

CKB3 é uma subunidade reguladora (beta) de CK2. Neste estudo, o mutante homozigoto ckb3 de Arabidopsis thaliana foi estudado para entender o papel da CKB3 na sinalização de ácido abscísico (ABA). Os resultados apresentados: CKB3 foi expresso em todos os órgãos e a maior expressão nas sementes, seguida pela raiz. Durante a germinação das sementes e o crescimento radicular, o mutante ckb3 mostrou sensibilidade reduzida ao ABA. O mutante ckb3 teve mais abertura estomática e aumento do acúmulo de prolina e perda de água nas folhas. Os níveis de expressão do número de genes na rede reguladora da ABA haviam mudado. Este estudo demonstra que CKB3 é um gene relacionado à sinalização ABA e pode desempenhar um papel positivo na sinalização ABA.

Control of Innate and Adaptive Lymphocytes by the RAR-Retinoic Acid Axis

Lymphocytes, such as T cells, B cells, and innate lymphoid cells (ILCs), play central roles in regulating immune responses. Retinoic acids (RAs) are vitamin A metabolites, produced and metabolized by certain tissue cells and myeloid cells in a tissue-specific manner. It has been established that RAs induce gut-homing receptors on T cells, B cells, and ILCs. A mounting body of evidence indicates that RAs exert far-reaching effects on functional differentiation and fate of these lymphocytes. For example, RAs promote effector T cell maintenance, generation of induced gut-homing regulatory and effector T cell subsets, antibody production by B cells, and functional maturation of ILCs. Key functions of RAs in regulating major groups of innate and adaptive lymphocytes are highlighted in this article.

Arabidopsis CK2 family gene CKB3 involved in abscisic acid signaling

Abstract CKB3 is a regulatory (beta) subunit of CK2. In this study Arabidopsis thaliana homozygous T-DNA mutant ckb3 was studied to understand the role of CKB3 in abscisic acid (ABA) signaling. The results shown: CKB3 was expressed in all organs and the highest expression in the seeds, followed by the root. During seed germination and root growth the ckb3 mutant showed reduced sensitivity to ABA. The ckb3 mutant had more stomatal opening and increased proline accumulation and leaf water loss. The expression levels of number of genes in the ABA regulatory network had changed. This study demonstrates that CKB3 is an ABA signaling-related gene and may play a positive role in ABA signaling.

Resumo CKB3 é uma subunidade reguladora (beta) de CK2. Neste estudo, o mutante homozigoto ckb3 de Arabidopsis thaliana foi estudado para entender o papel da CKB3 na sinalização de ácido abscísico (ABA). Os resultados apresentados: CKB3 foi expresso em todos os órgãos e a maior expressão nas sementes, seguida pela raiz. Durante a germinação das sementes e o crescimento radicular, o mutante ckb3 mostrou sensibilidade reduzida ao ABA. O mutante ckb3 teve mais abertura estomática e aumento do acúmulo de prolina e perda de água nas folhas. Os níveis de expressão do número de genes na rede reguladora da ABA haviam mudado. Este estudo demonstra que CKB3 é um gene relacionado à sinalização ABA e pode desempenhar um papel positivo na sinalização ABA.

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering

Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-based scaffolds in tissue engineering. Advances in the preparation, modification, and application of PHBHHx scaffolds are discussed.

Delivery of the Sox9 gene promotes chondrogenic differentiation of human umbilical cord blood-derived mesenchymal stem cells in an in vitro model

SRY-related high-mobility-group box 9 (Sox9) gene is a cartilage-specific transcription factor that plays essential roles in chondrocyte differentiation and cartilage formation. The aim of this study was to investigate the feasibility of genetic delivery of Sox9 to enhance chondrogenic differentiation of human umbilical cord blood-derived mesenchymal stem cells (hUC-MSCs). After they were isolated from human umbilical cord blood within 24 h after delivery of neonates, hUC-MSCs were untreated or transfected with a human Sox9-expressing plasmid or an empty vector. The cells were assessed for morphology and chondrogenic differentiation. The isolated cells with a fibroblast-like morphology in monolayer culture were positive for the MSC markers CD44, CD105, CD73, and CD90, but negative for the differentiation markers CD34, CD45, CD19, CD14, or major histocompatibility complex class II. Sox9 overexpression induced accumulation of sulfated proteoglycans, without altering the cellular morphology. Immunocytochemistry demonstrated that genetic delivery of Sox9 markedly enhanced the expression of aggrecan and type II collagen in hUC-MSCs compared with empty vector-transfected counterparts. Reverse transcription-polymerase chain reaction analysis further confirmed the elevation of aggrecan and type II collagen at the mRNA level in Sox9-transfected cells. Taken together, short-term Sox9 overexpression facilitates chondrogenesis of hUC-MSCs and may thus have potential implications in cartilage tissue engineering.

Gut Microbiota-Derived Short-Chain Fatty Acids, T Cells, and Inflammation

T cells are central players in the regulation of adaptive immunity and immune tolerance. In the periphery, T cell differentiation for maturation and effector function is regulated by a number of factors. Various factors such as antigens, co-stimulation signals, and cytokines regulate T cell differentiation into functionally specialized effector and regulatory T cells. Other factors such as nutrients, micronutrients, nuclear hormones and microbial products provide important environmental cues for T cell differentiation. A mounting body of evidence indicates that the microbial metabolites short-chain fatty acids (SCFAs) have profound effects on T cells and directly and indirectly regulate their differentiation. We review the current status of our understanding of SCFA functions in regulation of peripheral T cell activity and discuss their impact on tissue inflammation.

Biodistribution of 99mTc Labeled Integrin Antagonist

The selective targeting of an integrin alphavbeta3 receptor using radioligands may enable the assessment of angiogenesis and integrin alphavbeta3 receptor status in tumors. The aim of this research was to label a peptidomimetic integrin alphavbeta3 antagonist (PIA) with 99mTc(CO)3 and to test its receptor targeting properties in nude mice bearing receptor-positive tumors. PIA was reacted with tris-succinimidyl aminotriacetate (TSAT) (20 mM) as a PIA per TSAT. The product, PIA-aminodiacetic acid (ADA), was radiolabeled with [99mTc(CO)3(H2O)3](+1), and purified sequentially on a Sep-Pak C-18 cartridge followed by a Sep-Pak QMA anion exchange cartridge. Using gradient C-18 reverse-phase HPLC, the radiochemical purity of 99mTc(CO)3-ADA-PIA (retention time, 10.5 min) was confirmed to be > 95%. Biodistribution analysis was performed in nude mice (n = 5 per time point) bearing receptor-positive M21 human melanoma xenografts. The mice were administered 99mTc(CO)3-ADA-PIA intravenously. The animals were euthanized at 0.33, 1, and 2 hr after injection for the biodistribution study. A separate group of mice were also co-injected with 200 microg of PIA and euthanized at 1 hr to quantify tumor uptake. 99mTc(CO)3-ADA-PIA was stable in phosphate buffer for 21 hr, but at 3 and 6 hr, 7.9 and 11.5% of the radioactivity was lost as histidine, respectively. In tumor bearing mice, 99mTc(CO)3-ADA-PIA accumulated rapidly in a receptor-positive tumor with a peak uptake at 20 min, and rapid clearance from blood occurring primarily through the hepatobiliary system. At 20 min, the tumor-to-blood ratio was 1.8. At 1 hr, the tumor uptake was 0.47% injected dose (ID)/g, but decreased to 0.12% ID/g when co-injected with an excess amount of PIA, indicating that accumulation was receptor mediated. These results demonstrate successful 99mTc labeling of a peptidomimetic integrin antagonist that accumulated in a tumor via receptor-specific binding. However, tumor uptake was very low because of low blood concentrations that likely resulted from rapid uptake of the agent into the hepatobiliary system. This study suggests that for 99mTc(CO)3-ADA-PIA to be useful as a tumor detection agent, it will be necessary to improve receptor binding affinity and increase the hydrophilicity of the product to minimize rapid hepatobiliary uptake.

Vanishing Pancreatic Grafts

Comparison of pancreaticoduodenal transplants (PDT) and duct-ligated pancreas transplant (DLPT) were performed using syngeneic and allogeneic studies in rats. Both DLPT and PDT allogeneic grafts showed mild rejection. DLPT groups showed disorganized pathology and acini replaced by fat. Eventually, massive fibrosis was seen in the Islets of Langerhans, as well as rejection cellular infiltrates. In both PDT groups, normal histology was observed in the same period. Thus the effect of duct occlusion is highly detrimental for the grafts.

Biodistribution and Hepatic Metabolism of Galactosylated 111In-Antibody-Chelator Conjugates: Comparison with 111In-Antibody-Chelator Conjugates / 대한핵의학회잡지

PURPOSE: To evaluate the use of monoclonal antibody (MoAb) as a carrier of the receptor-binding ligand, the receptor mediated uptake into liver and subsequent metabolism of (111) In-labeled galactosylated MoAb-chelator conjugates were investigated and compared with those of (111) In labeled MoAb. MATERIALS AND METHODS: T101 MoAb, IgG2 against human lymphocytic leukemic cell, conjugated with cyclic DTPA dianhydride (DTPA) or 2-p-isothiocyanatobenzyl-6-methyl-DTPA (1B4M) was galactosylated with 2-imino-2-methoxyethyl-1-thio-beta-D-galactose and then radiolabeled with (111) In. Biodistribution and metabolism study was performed with two (111) In-conjugates in mice and rats. RESULTS: (111) In-labeled T101 and its galactosylated conjugates were taken to the liver by the time, mostly within 10 min. However DTPA conjugate was retained longer in the liver than the 1B4M conjugate (55% vs 20% of injected dose at 44 hr). During this time, the radiometabolite of DTPA conjugate was excreted similarly into urine (24%) and feces (17%). The radiometabolite of 1B4M was excreted primarily into feces (68%) rather than urine (8%). Size exclusion HPLC analysis of the bile and supernatant of liver homogenate showed two peaks, the first (35%) with the retention time (Rt) identical to IgG and the second (65%) with Rt similar to free 111In at 3 hr post-injection for the 1B4M conjugate, indicating that the metabolite is rapidly excreted through the biliary system. In contrast to DTPA conjugate, the small (111) In-DTPA-like metabolite was the major radioindium component (90%) in the liver homogenate as early as 3 hour post-injection, but the cumulative radioindium activity in feces was only 17% at 44 hour, indicating that the metabolite from DTPA conjugate does not clear readily through the biliary tract. CONCLUSION: The galactosylation of the MoAb conjugates resulted in higher hepatocyte uptake and enhanced metabolism, compared to those without galactosylation. Metabolism of the MoAb-conjugates is different between compounds radiolabled with different chelators due to different characteristics of radiometabolites generated in the liver.

Vascular biology and stroke.

The pathophysiology of stroke is complex and involves an abnormal interaction between vessel wall and platelets. Of late many genetic and environmental factors impinging on the vessel wall have been identified which may determine the susceptibility of an individual to stroke. These include elevated homocysteine levels, chronic chalymydial and periodontal infection, plaque characteristics and genetic susceptibility. Intervention with HMG CO enzyme A reductase inhibitors, Angiotensin Enzyme Inhibitors and vitamins have been shown to offer protection.

Persistent hypoglycemic hemiplegia: A case report

Hypoglycemia sometimes manifests as focal neurologic deficits simulating cerebrovascular disease. Symptoms are usually resolved by glucose infusion, but persistent hemiplegia is rarely reported. A 68-year-old diabetic woman on oral hypoglycemic agent(OHA) was admitted with right hemiplegia and global aphasia. Blood glucose level was 29 mg/dl on admission. No evidence of cerebral infarct or underlying brain disease could be found on initial brain CT and follow up MRI. Focal stenosis or occlusion was also absent on MR angiography. Hemiplegia and aphasia were not improved despite adequate therapy. Hypoglycemic hemiplegia should be suspected in all diabetic patients using insulin or OHA with stroke-like episode, and we suggest that prolonged hypoglycemia may be related to persistence of neurologic deficits.

Lipoprotein oxidation: implications to atherogenesis

Lipoprotein modification is a critical step in the development of atherosclerosis. Oxidant species released by endothelial cells, smooth muscle cells, monocytes, neutrophils, macrophages and platelets can oxidatively modify lipoproteins. Oxidized lipoproteins generated in vivo may participate in the atherogenic process by different mechanisms. This review will focus on the processes leading to lipoprotein oxidation, the interactions of oxidized lipoproteins with vascular endothelium and their participation in atheroma formation, the disturbances induced by lipoprotein oxidative modifications on intravascular lipoprotein metabolism, and the occurrence of oxidative stress in subjects with hyperlipoproteinemia. The elucidation of these events may be important to establish future preventive strategies and therapeutic approaches for atherosclerosis.

Comparison of multiplex PCR and culture for detection of Legionellae in cooling tower water samples.

We compared multiplex polymerase chain reaction (PCR) and culture for detecting the presence of Legionella pneumophila and Legionella spp in cooling tower water samples. Multiplex PCR was performed after phenol extraction of DNA from the samples. The set of primers for the PCR assay involved the 5S rRNA (Legionella spp) and the mip (macrophage infectivity potentiator gene, specific for L. pneumophila) genes as target sequences for amplification. Both the sensitivity and the specificity of the PCR assay were 100% when the 5S rRNA gene was used as target sequence. Isolation of Legionellae from the samples was observed only with the PCR-positive samples. We propose that PCR be used as a screening test before attempting to culture Legionellae from cooling tower water samples.