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Alpha1-antitrypsin deficiency and inflammatory bowel diseases.

OBJECTIVE: To evaluate a possible etiologic role of alpha1-antitrypsin deficiency (alpha1AD), most frequently caused by a Z allele mutation, in ulcerative colitis (UC) and Crohn disease (CD). PATIENTS AND METHODS: This retrospective study included 10 patients diagnosed with and/or treated for inflammatory bowel disease (IBD) between 1976 and 1997 and identified from the Mayo Clinic Medical Index System. All 10 patients had either alpha1AD and CD or alpha1AD and UC. The alpha1-antitrypsin (alpha1AT) types and levels were determined with isoelectric focusing testing. The allele types, representing genotypes, were designated PiZZ (or ZZ) for homozygotes and PiMZ (or MZ) for heterozygotes. RESULTS: Seven patients had UC: 4 were genotype ZZ and 3 MZ. Four of these 7 patients had emphysema, 2 had asthma, and 1 had chronic bronchitis. Five were cigarette smokers, but only 1 had smoked coincident with activity of her UC. Two of the UC patients never smoked, and 1 of these 2 had asthma. Three of the 10 patients had CD, 2 genotype ZZ and 1 MZ. Two of the 3 patients were long-term cigarette smokers, and both had emphysema. Nine of the 10 patients with UC and alpha1AD required surgery. CONCLUSIONS: The need for surgery in patients with UC and alpha1-AD may point to a unique phenotypic subgroup of patients with alpha1AD and severe UC. Further studies are required to substantiate the etiologic role of alpha1AD in IBD. Our observations, if confirmed by future studies, suggest that in patients with both IBD and chronic obstructive pulmonary disease, alpha1AD testing should be considered.

Adult↗

CD1d deficiency exacerbates inflammatory dermatitis in MRL-lpr/lpr mice.

Mechanisms responsible for the development of autoimmune skin disease in humans and animal models with lupus remain poorly understood. In this study, we have investigated the role of CD1d, an antigen-presenting molecule known to activate natural killer T cells, in the development of inflammatory dermatitis in lupus-susceptible MRL-lpr/lpr mice. In particular, we have established MRL-lpr/lpr mice carrying a germ-line deletion of the CD1d genes. We demonstrate that CD1d-deficient MRL-lpr/lpr mice, as compared with wild-type littermates, have more frequent and more severe skin disease, with increased local infiltration with mast cells, lymphocytes and dendritic cells, including Langerhans cells. CD1d-deficient MRL-lpr/lpr mice had increased prevalence of CD4(+) T cells in the spleen and liver and of TCR alpha beta (+)B220(+) cells in lymph nodes. Furthermore, CD1d deficiency was associated with decreased T cell production of type 2 cytokines and increased or unchanged type 1 cytokines. These findings indicate a regulatory role of CD1d in inflammatory dermatitis. Understanding the mechanisms by which CD1d deficiency results in splenic T cell expansion and cytokine alterations, with increased dermal infiltration of dendritic cells and lymphocytes in MRL-lpr/lpr mice, will have implications for the pathogenesis of inflammatory skin diseases.

Animals↗

Differential gene expression profiles in the hippocampus of senescence-accelerated mouse.

The senescence-accelerated mouse (SAM) is an animal model for studying senescence and age-associated disorders due to its inherited aging phenotype. The SAM/prone8 (SAMP8) is a useful animal model to investigate the fundamental mechanisms involved in age-related learning and memory deficits that may have relevance to age-associated AD, while SAM/resistant1 (SAMR1) shows normal. To identify genes rendering the cognitive deterioration with aging, the subtractive cDNA libraries containing 1924 clones with the positive ratio of 96.18% were generated and the microarray containing 3136 cDNA was prepared. The results of screening libraries by the microarray showed that of all 91 differentially expressed genes, 50 were over-expressed and 41 were low-expressed in SAMP8. Some of the identified genes were confirmed by the real time quantitative RT-PCR. These results indicated the profiles of gene expression in the hippocampus of SAMP8 and SAMR1 were significantly different, which may play important roles in the age-related cognitive deficit in SAMP8, suggesting those genes related to the cognitive deficient or pathology change in the brain of SAMP8 may be potential gene targets for Alzheimer's disease therapy.

Aging↗

P27 knockout mice: reduced myostatin in muscle and altered adipogenesis.

Knockout of the P27(kip) gene, which encodes a cyclin-dependent kinase inhibitor involved in cell proliferation regulation, results in growth enhancement in mice. To investigate how p27 deficiency affected adipogenesis and myogenesis, levels of PPARgamma, C/EBPalpha, and the myogenesis inhibitor, myostatin, were measured in p27(-/-) (n=14), p27(+/-) (n=18), and p27(+/+) mice (n=11). Body weight and gastrocnemius muscle (GC) mass were increased in p27(-/-) mice (P<0.05), but there were no differences in fat depot weights, percent body fat or serum leptin concentrations among genotypes. PPARgamma, but not C/EBPalpha, was markedly increased in p27(-/-) mice (P<0.05). There was also a higher incidence of inguinal fat apoptosis (P<0.01) in p27(-/-) mice. Myostatin levels were reduced in GC muscle of p27(-/-) mice (P<0.05). These findings suggest that in p27 deficient mice, increased skeletal muscle mass is mediated in part through decreased myostatin. Although total adiposity was not changed, increased PPARgamma levels suggest an alteration in adipogenesis.

Adipose Tissue↗

Impaired nonhomologous end-joining in mismatch repair-deficient colon carcinomas.

Frameshift mutations of coding mononucleotide repeat of the hRAD50 gene and formation of the mutant hMRE11 splicing variant are frequent events in tumors with mismatch repair (MMR) deficiency. Both the hRAD50 and hMRE11 proteins form a heterotrimer with the NBS1, and this heterotrimer is involved in the double strand DNA break repair by homologous recombination and nonhomologous end-joining (NHEJ). In order to clarify the role of hRAD50 and hMRE11 gene alterations in MMR-deficient tumors, we analyzed the expression of the hRAD50 and hMRE11 proteins and we evaluated NHEJ in the seven MMR-deficient and five MMR-proficient colon cancer cell lines. Frameshift mutations of the hRAD50 gene were found in five of seven MMR-deficient cell lines, and this was directly related to the decreased expression of hRAD50 mRNA and protein. The mutant hMRE11 splicing variant was found in all of the seven MMR-deficient cell lines, and this was related to the decreased hMRE11 expression in four of the seven MMR-deficient cell lines. MMR-deficient cell lines with decreased hRAD50 and hMRE11 expressions were more sensitive to gamma-irradiation, and these cell lines showed an impaired NHEJ. The impairment of NHEJ was induced after knockdown of hRAD50 and hMRE11 through small interference RNA. Our findings suggest that mutations of hRAD50 and hMRE11 genes in MMR-deficient tumors are related to the defects in NHEJ, and this may result in chromosomal changes during the progression of tumor.

Acid Anhydride Hydrolases↗

Functional interaction of H2AX, NBS1, and p53 in ATM-dependent DNA damage responses and tumor suppression.

Ataxia-telangiectasia (A-T) mutated (ATM) kinase signals all three cell cycle checkpoints after DNA double-stranded break (DSB) damage. H2AX, NBS1, and p53 are substrates of ATM kinase and are involved in ATM-dependent DNA damage responses. We show here that H2AX is dispensable for the activation of ATM and p53 responses after DNA DSB damage. Therefore, H2AX functions primarily as a downstream mediator of ATM functions in the parallel pathway of p53. NBS1 appears to function both as an activator of ATM and as an adapter to mediate ATM activities after DNA DSB damage. Phosphorylation of ATM and H2AX induced by DNA DSB damage is normal in NBS1 mutant/mutant (NBS1m/m) mice that express an N-terminally truncated NBS1 at lower levels. Therefore, the pleiotropic A-T-related systemic and cellular defects observed in NBS1m/m mice are due to the disruption of the adapter function of NBS1 in mediating ATM activities. While H2AX is required for the irradiation-induced focus formation of NBS1, our findings indicate that NBS1 and H2AX have distinct roles in DNA damage responses. ATM-dependent phosphorylation of p53 and p53 responses are largely normal in NBS1m/m mice after DNA DSB damage, and p53 deficiency greatly facilitates tumorigenesis in NBS1m/m mice. Therefore, NBS1, H2AX, and p53 play synergistic roles in ATM-dependent DNA damage responses and tumor suppression.

Animals↗

The transcription factor gene Nfib is essential for both lung maturation and brain development.

The phylogenetically conserved nuclear factor I (NFI) gene family encodes site-specific transcription factors essential for the development of a number of organ systems. We showed previously that Nfia-deficient mice exhibit agenesis of the corpus callosum and other forebrain defects, whereas Nfic-deficient mice have agenesis of molar tooth roots and severe incisor defects. Here we show that Nfib-deficient mice possess unique defects in lung maturation and exhibit callosal agenesis and forebrain defects that are similar to, but more severe than, those seen in Nfia-deficient animals. In addition, loss of Nfib results in defects in basilar pons formation and hippocampus development that are not seen in Nfia-deficient mice. Heterozygous Nfib-deficient animals also exhibit callosal agenesis and delayed lung maturation, indicating haploinsufficiency at the Nfib locus. The similarity in brain defects in Nfia- and Nfib-deficient animals suggests that these two genes may cooperate in late fetal forebrain development, while Nfib is essential for late fetal lung maturation and development of the pons.

Agenesis of Corpus Callosum↗

Macrophage migration inhibitory factor deficiency impairs atherosclerosis in low-density lipoprotein receptor-deficient mice.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine expressed widely by vascular cells. However, scant in vivo evidence supports direct participation of MIF in atherogenesis. Therefore, we investigated whether deficiency of MIF modulates atherosclerotic lesion formation and composition in low-density lipoprotein receptor-deficient (LDLr-/-) mice. METHODS AND RESULTS: MIF-/-LDLr-/- and LDLr-/- mice were generated and consumed an atherogenic diet for 12 or 26 weeks. MIF-/-LDLr-/- mice had significantly reduced abdominal aorta lipid deposition and intimal thickening from aortic arch throughout the abdominal aorta compared with LDLr-/- mice. Marked retardation of atherosclerosis over time in MIF-deficient mice accompanied decreased lesion cell proliferation. At 26 weeks, 20% of MIF-deficient mice developed only early, fatty streak-like lesions, whereas >80% of LDLr-/- mice developed advanced lesions containing calcification and lipid cores. Analysis of smooth muscle cells from mouse aortae demonstrated that MIF deficiency reduced smooth muscle cell proliferation, cysteine protease expression, and elastinolytic and collagenolytic activities. CONCLUSIONS: Deficiency of MIF reduces atherogenesis in LDLr-/- mice. These results provide novel insight into inflammatory pathways operating in atheromata and identify a new potential target for modulating atherogenesis.

Animals↗

Absence of alpha-1 antitrypsin deficiency alleles (S and Z) in Japanese and Korean patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: A possible association has been proposed for the formation of intracranial aneurysm (IA) and deficiency alleles (S and Z) of the alpha1-antitrypsin (AAT) gene. We extensively screened this gene in Japanese and Korean patients with aneurysmal subarachnoid hemorrhage. METHODS: Seven allelic variants, including S and Z alleles, were genotyped by direct sequencing of genomic DNA obtained from 195 and 189 ruptured IA patients and 195 and 94 controls in Japanese and Koreans, respectively. The haplotype in phase-unknown samples was constructed with the expectation-maximization method. Differences in allelic frequencies between patients and controls were evaluated by Fisher exact test. RESULTS: No significant differences in allelic frequencies were observed at all 7 variants between ruptured IA patients and controls. We could not detect the S and Z alleles of the AAT gene in Japanese and Korean populations. CONCLUSIONS: AAT deficiency may not be a common genetic risk factor for aneurysmal subarachnoid hemorrhage in Japanese and Koreans.

Asian People↗

Apoptotic insults impair Na+, K+-ATPase activity as a mechanism of neuronal death mediated by concurrent ATP deficiency and oxidant stress.

The Na+, K+-ATPase (Na+, K+-pump) plays critical roles in maintaining ion homeostasis. Blocking the Na+, K+-pump may lead to apoptosis. By contrast, whether an apoptotic insult may affect the Na+, K+-pump activity is largely undefined. In cultured cortical neurons, the Na+, K+-pump activity measured as a membrane current Ipump was time-dependently suppressed by apoptotic insults including serum deprivation, staurosporine, and C2-ceramide, concomitant with depletion of intracellular ATP and production of reactive oxygen species. Signifying a putative relationship among these events, Ipump was highly sensitive to changes in ATP and reactive oxygen species levels. Moreover, the apoptosis-associated Na+, K+-pump failure and serum deprivation-induced neuronal death were antagonized by pyruvate and succinate in ATP- and reactive-oxygen-species-dependent manners. We suggest that failure of the Na+, K+-pump as a result of a combination of energy deficiency and production of reactive oxygen species is a common event in the apoptotic cascade; preserving the pump activity provides a neuroprotective strategy in certain pathological conditions.

Adenosine Diphosphate↗

Histiocytic medullary reticulosis: radiologic diagnosis of splenic infarction--a case report.

A case of histiocytic medullary reticulosis with splenic infaraction from a 23-year-old male is presented. Radiologic findings on selective spleen scintigraphy and abdominal CT are described. Selective spleen scintigraphy showed huge, multilobulated spleen with numerous photon-deficient areas in it and peripherally. Abdominal CT showed large peripheral band-like low density and infiltrative lesion in spleen with accompanying intraabdominal lymphadenopathy. Histoligical features were consistent with HMR in spleen and liver specimens.

Adult↗

[Priority of selenium incorporation into selenoproteins during selenium depletion in rats].

Male weanling Wistar rats were fed with either a basal selenium deficient diet (a Torula yeast based semisynthetic diet, containing Se 0.01 mg/kg) or a selenium sufficient diet supplemented with Se as Na2SeO3 (containing Se 0.5 mg/kg). Rats were killed after different weeks(0,1,2,4,8,12,15,17,19,20 and 24 respectively). Their organs were taken to observe the kinetic change of selenium concentration, the activities of intracellular glutathione peroxidase (cGPX), extracellular glutathione peroxidase (eGPX), and phospholipid hydroperoxide glutathione peroxidase (PHGPX) in different organs. The results showed that selenium levels and the activities of selenoenzyme in testis and pituitary were more resistant to selenium deficiency than other organs. During selenium deficiency, the utilization of selenium by PHGPX and deiodinase was prior to eGPX and cGPX, which suggested that the function of PHGPX and deiodinase were more important than that of eGPX and cGPX.

Animals↗

Overexpression of the natural recO sequence and its effects on DNA repair of Escherichia coli.

The recO gene is required for the RecF pathway of recombination and the repair of DNA daughter-strand gaps in Escherichia coli. In this work, the structural portion of recO was synthesized by the polymerase chain reaction (PCR) and cloned onto expression vectors at their Nco1 fusion cloning site, to eliminate the presence of mRNA leader sequence. While the plasmid carrying a Ptac promoter failed to overproduce RecO, the plasmid carrying a T7O10 promoter overproduced RecO in large quantity, indicating that the natural recO may be overexpressed. An increase of intracellular RecO, which may be due to the increased recO gene copies or to the induction of RecO synthesis, increased the UV resistance of recA, recF, and ssb cells, but did not increase the UV resistance of uvrB, uvrB recF, uvrB recA and uvrB ssb cells. We suggest that an increase of intracellular RecO may allow some recombination-deficient cells to perform more excision repair, thus increasing the survival. The possible causes for RecO overproduction on excision repair, and for the differential expression of recO by the Ptac and T7 promoter plasmids are discussed.

Bacterial Proteins↗

Maternal vitamin B12 deprivation exacerbates offspring obesity by reducing early-life colonization with Bifidobacterium pseudolongum.

Vitamin B12 deficiency during pregnancy and lactation is common, yet its mechanistic impact on reproductive outcomes and offspring health remains poorly understood. Here, we show that maternal dietary vitamin B12 deprivation not only impairs maternal glucose metabolism and reproductive outcomes but also exacerbates high-fat-diet-induced obesity in offspring. These effects are mediated by gut microbiota and associated with a marked reduction of Bifidobacterium pseudolongum (B. pseudolongum) in both dams and their offspring. Maternal vitamin B12 deprivation limits early-life acquisition of B. pseudolongum in offspring during lactation, subsequently intensifying obesity and metabolic dysregulation. Early-life restoration of B. pseudolongum or its key metabolite, acetate, effectively ameliorates this aggravated obesity. Mechanistically, acetate acts through the Ffar2 receptor to upregulate Ehhadh expression. Together, these data establish that perinatal nutrition imprints long-term metabolic phenotypes in offspring via early-life acquisition of the gut microbiota, with a critical window during lactation.

Animals↗

Association of B vitamins status and homocysteine levels in elderly Taiwanese.

To investigate the relationship between homocysteine (Hcy) and B vitamins status in the Taiwanese elderly population, an analysis was made of the plasma Hcy levels in elderly persons. The study sample was taken from the Elderly Nutrition and Health Survey in Taiwan (1999-2000) (Elderly NAHSIT) and included 1094 males and 1135 females aged 65-90 years. The results showed that average plasma Hcy was 13.3+/-0.6 micromol/ L for males and 10.6+/-0.7 micromol/L for females. The average plasma Hcy levels of males from all age groups were significantly higher than those of females, and significantly increased with age (P<0.0001). The overall prevalence of hyperhomocysteinemia (Hcy>15 micromol/L) was 23.4% for elderly males and 11.2% for elderly females, and this also increased with age (P<0.0001). In subjects with normal renal function, folate, vitamin B2, B6, and B12 status were significantly lower in males with hyperhomocysteinemia, while only folate and vitamin B12 were significantly lower in females with hyperhomocysteinemia. Further analysis suggested that folate, vitamin B6 or B12 insufficiency were associated with hyperhomocysteinemia in both sexes, while vitamin B2 insufficiency was significantly associated only in males. In elderly persons with adequate folate, vitamin B6, and B12 status, there was no significant association between vitamin B2 and hyperhomocysteinemia. This association occurred only in those who had concurrent poor folate, vitamin B6, or B12 status. The strength of the association between vitamin B12 insufficiency and hyperhomocysteinemia was not affected by simultaneous vitamin B2 or B6 insufficiency, but increased about 3-fold when combined with folate. This suggests that poor folate and vitamin B12 status has a synergistic effect on the risk of hyperhomocysteinema in the elderly, as did a poor folate and vitamin B6 status. Therefore, maintaining adequate vitamin B12 status and avoiding multiple B vitamin insufficiency, especially that of folate and vitamin B12 or B6, should be emphasized as an important measure for reducing plasma Hcy levels among elderly Taiwanese.

Age Factors↗

Fe-S cluster deficiency drives small colony variant formation in persistent infections.

INTRODUCTION: Small colony variants (SCVs) of Staphylococcus aureus (S. aureus) are associated with persistent infections and poor clinical outcomes. The mechanisms driving stable SCV formation remain poorly understood, particularly concerning metabolic adaptations. This study explores the in-host evolutionary dynamics of S. aureus and identifies a novel genetic determinant linked to SCV formation. OBJECTIVES: To investigate the genetic mutations and phenotypic adaptations underlying SCV formation, with a focus on the role of a novel mutation in the sufB gene, which is critical for Fe-S cluster biosynthesis. METHODS: Sequential isolates from a patient with recurrent infections were analyzed using whole-genome sequencing, antimicrobial susceptibility testing, and functional assays. The phylogenetic relationship of the isolates was determined, and specific mutations were identified. Functional assays included aconitase and glutamate synthase activity measurements, ATP level quantification, reactive oxygen species (ROS) production, and biofilm formation assays. In vivo pathogenesis was assessed using a murine catheter infection model. RESULTS: A novel frameshift mutation in sufB was identified, disrupting Fe-S cluster biosynthesis and impairing the TCA cycle and electron transport chain, leading to reduced ATP and ROS production. This metabolic reprogramming promoted stable SCV formation, characterized by slow growth, enhanced tolerance to antibiotics and neutrophil-mediated killing, and persistent inflammation in vivo. Restoration of sufB reversed these phenotypes, confirming its pivotal role in SCV-associated persistence. CONCLUSION: sufB is a novel genetic determinant of stable SCV formation through Fe-S cluster deficiency, driving metabolic shifts that enhance immune evasion and chronic infection. Our findings highlight antibiotic stewardship and suggest potential therapeutic strategies for managing persistent SCV-associated infections.

Staphylococcus aureus↗

Mediation of tubuloglomerular feedback by adenosine: evidence from mice lacking adenosine 1 receptors.

Adenosine is a determinant of metabolic control of organ function increasing oxygen supply through the A2 class of adenosine receptors and reducing oxygen demand through A1 adenosine receptors (A1AR). In the kidney, activation of A1AR in afferent glomerular arterioles has been suggested to contribute to tubuloglomerular feedback (TGF), the vasoconstriction elicited by elevations in [NaCl] in the macula densa region of the nephron. To further elucidate the role of A1AR in TGF, we have generated mice in which the entire A1AR coding sequence was deleted by homologous recombination. Homozygous A1AR mutants that do not express A1AR mRNA transcripts and do not respond to A1AR agonists are viable and without gross anatomical abnormalities. Plasma and urinary electrolytes were not different between genotypes. Likewise, arterial blood pressure, heart rates, and glomerular filtration rates were indistinguishable between A1AR(+/+), A1AR(+/-), and A1AR(-/-) mice. TGF responses to an increase in loop of Henle flow rate from 0 to 30 nl/min, whether determined as change of stop flow pressure or early proximal flow rate, were completely abolished in A1AR(-/-) mice (stop flow pressure response, -6.8 +/- 0.55 mmHg and -0.4 +/- 0.2 in A1AR(+/+) and A1AR(-/-) mice; early proximal flow rate response, -3.4 +/- 0.4 nl/min and +0.02 +/- 0.3 nl/min in A1AR(+/+) and A1AR(-/-) mice). Absence of TGF responses in A1AR-deficient mice suggests that adenosine is a required constituent of the juxtaglomerular signaling pathway. A1AR null mutant mice are a promising tool to study the functional role of A1AR in different target tissues.

Adenosine↗