A role of inhibitor of apoptosis (IAP) proteins in increased lymphocyte apoptosis in aged humans

Lymphocytes from aged humans show increased death-receptor-mediated apoptosis, which is associated with an increased and early activation of caspases. Inhibitor of apoptosis (IAP) proteins inhibit apoptosis by inhibiting activation and activity of caspases. Therefore, we examine the expression of two of the IAPs, the cIAP-2 and XIAP in lymphocytes from young and aged subjects by Western blotting. Lymphocytes from aged expressed significantly less cIAP2 whereas no difference was observed in XIAP expression between young and aged subjects. These data may suggest that decreased cIAP2 may play a role in increased apoptosis in aged humans. Possible mechanisms for the regulation of IAPs in aging are discussed.     

Recessive 2-(methylamino)-isobutyrate (MeAIB) -resistant mutant of Chinese hamster ovary cells (CHO-K1) with increased transport through ASC system

Mutants of Chinese hamster ovary cells (CHO-K1 Pro^–), resistant to the proline transport antagonist 2-(methylamino)-isobutyrate (MeAIB) were isolated by a singlestep procedure. Mutation rates to Pro⁺ and to Pro^– MeAIB resistance (MeAIB^r) are 1.7×10^–6 and 2.4×10^–5, respectively. Several Pro^– MeAIB^r mutants were tested by measuring the uptake of 0.05 mM proline through the various amino acid transport systems: some showed increases in one transport system only; others revealed pleiotropic changes affecting two or more systems; still others had no apparent change in proline transport. One Pro^– MeAIB^r mutant analyzed in detail (MeAIB^r22) was isolated after EMS treatment as resistant to 5 mM MeAIB, is Pro^–, stable, and shows a 1.6-fold increase in the initial velocity of transport of 0.05 mM proline. There appears to be no change in the velocity of proline transport through the amino acid transport systems A, P, and L, and the glutamine inhibitable fraction. In contrast, there is a 5.5-fold increase in the velocity of transport of 0.05 mM proline through the ASC system. Kinetic studies reveal a sixfold increase in the V_m and a slight increase in the K_m of the transport of serine through the ASC system. Hybrids between MeAIB^r22 and CHO-Kl Pro^–, OVA^r, HPRT^– showed the parental phenotype. These results indicate that the mutant ASC phenotype of MeAIB^r22 is recessive and is probably the result of a regulatory gene mutation.     

Anti-glutathione S-transferase omega 1-1 (GSTO1-1) antibodies are increased during acute and chronic inflammation in humans

Glutathione S-transferase omega-1 (GSTO1-1) is a cytosolic enzyme involved in the modulation of critical inflammatory pathways as well as in cancer progression. Auto-antibodies against GSTO1-1 were detected in the serum of patients with esophageal squamous cell carcinoma and were proposed as potential biomarkers in the early detection of the disease. Our findings show that anti-GSTO1-1 antibodies can be found in a variety of inflammatory diseases, including autoimmune rheumatoid arthritis, infectious SARS-CoV-2, and trichinellosis. Our findings strongly suggest that anti-GSTO1-1 antibodies may be a marker of tissue damage/inflammation rather than a specific tumor-associated biomarker.     

Rescue of renal hypoplasia and cystic dysplasia in Bcl-2 -/- mice expressing Bcl-2 in ureteric bud derived epithelia

Bcl-2 is the founding member of a family of proteins that influence apoptosis. Loss of bcl-2 results in renal hypoplasia/cystic dysplasia at birth. Here, we examined whether re-expression of bcl-2 throughout the ureteric bud and its derived epithelia would restore a normal renal phenotype in bcl-2 -/- mice. Re-expression of bcl-2 in the ureteric bud/collecting duct of bcl-2 -/- mice increased nephron numbers, diminished glomerular hypertrophy, and increased nephrogenic zone size. Unlike bcl-2 -/- mice which have gross renal cyst formation, few renal cysts were present in mice re-expressing bcl-2. We have previously shown increased apoptosis and proliferation, as well as aberrant protein tyrosine phosphatase 1B expression, accompanied cystic changes in bcl-2 -/- mice. These changes were not observed when bcl-2 was re-expressed in the ureteric bud/collecting duct system. Thus, expression of bcl-2 in the ureteric bud/collecting duct resulted in increased nephron numbers partially rescuing renal hypoplasia/cystic dysplasia in bcl-2 -/- mice. Developmental Dynamics 237:2450-2459, 2008. (c) 2008 Wiley-Liss, Inc.     

Impaired dendritic cell maturation and increased T(H)2 responses in PIR-B(-/-) mice

Mice deficient for paired immunoglobulin (Ig)-like receptor B (PIR-B) show defective regulation of receptor-mediated activation in antigen-presenting cells. Older PIR-B(-/-) mice had an increased number of peritoneal B1 cells. Splenic PIR-B(-/-) B2 cells were constitutively activated and proliferated much more than those from wild-type mice upon B cell receptor ligation. T helper type 2 (T(H)2)-prone humoral responses were augmented in PIR-B(-/-) mice upon immunization with T-dependent antigens, including increased interleukin 4 and decreased interferon-gamma responses, as well as enhanced IgG1 and IgE production. Impaired maturation of dendritic cells (DCs), possibly due to perturbed intracellular signaling, was responsible for the skewed responses. Thus, PIR-B is critical for B cell suppression, DC maturation and for balancing T(H)1 and T(H)2 immune responses.     

Resistance of CD1d-/- mice to ultraviolet-induced skin cancer is associated with increased apoptosis

Inhibition of p53-induced epidermal apoptosis, generation of p53 mutations, and suppressor T cells are the critical events responsible for the induction and development of UV-induced skin cancers. Recently, we demonstrated that CD1d knockout mice were resistant to UV-induced immunosuppression, prompting us to further address the role of CD1d in regulating UV carcinogenesis. We, therefore, investigated the response of wild-type (WT) and CD1d-/- mice to UV carcinogenesis. We found that although 100% of WT mice developed skin tumors after 45 weeks of UV irradiation, only 60% of CD1d-/- mice developed skin tumors. Surprisingly, keratinocytes and fibroblasts from CD1d-/- mice were more sensitive to UV-induced apoptosis and persisted longer than cells derived from WT mice. In addition, epidermis and dermis taken from chronically UV-irradiated CD1d-/- mice harbored significantly fewer p53 mutations than WT mice. Our findings identify an unexpected and novel function for CD1d as a critical molecule regulating UV carcinogenesis, by inhibiting apoptosis to prevent elimination of potentially malignant keratinocytes and fibroblasts.     

Pneumococcal infections in humans are associated with increased apoptosis and trafficking of type 1 cytokine-producing T cells

Streptococcus pneumoniae infections are associated with considerable morbidity and mortality throughout the world. The immunopathology is characterized by an intense inflammatory reaction, including a strong acute-phase response and increased numbers of neutrophils in the circulation. However, little is known regarding the T-cell response during in vivo infections in humans. The purpose of this study was to test the hypothesis that activated T cells producing type 1 cytokines were engaged in the host response to pneumococcal infections. The phenotype and function of T cells were studied in 22 patients at admission to a department of infectious diseases and after antibiotic treatment for 1 week compared with an age-matched, healthy control group. Pneumococcal infections induced lymphopenia in the circulation due to the disappearance of activated T lymphocytes with a type 1 cytokine profile. In contrast, the numbers of naive T cells and interleukin-4-producing T cells did not change. Activated type 1 cytokine-producing cells reappeared in the circulation in relation to the treatment and clinical improvement. The underlying mechanisms during infection may include sequestration in the peripheral tissues and/or apoptosis. In fact, increased activation-induced apoptosis in the remaining peripheral lymphocytes and elevated levels of soluble Fas ligand were detected at admission to the hospital. In conclusion, these data suggest that activated T lymphocytes with a type 1 cytokine profile are highly engaged in the in vivo immune response to S. pneumoniae.     

Growth retardation and increased apoptosis in mice with homozygous disruption of the akt1 gene

The serine/threonine kinase Akt has been implicated in the control of cell survival and metabolism. Here we report the disruption of the most ubiquitously expressed member of the akt family of genes, akt1, in the mouse. Akt1(-/-) mice are viable but smaller when compared to wild-type littermates. In addition, the life span of Akt1(-/-) mice, upon exposure to genotoxic stress, is shorter. However, Akt1(-/-) mice do not display a diabetic phenotype. Increased spontaneous apoptosis in testes, and attenuation of spermatogenesis is observed in Akt1(-/-) male mice. Increased spontaneous apoptosis is also observed in the thymi of Akt1(-/-) mice, and Akt1(-/-) thymocytes are more sensitive to apoptosis induced by gamma-irradiation and dexamethasone. Finally, Akt1(-/-) mouse embryo fibroblasts (MEFs) are more susceptible to apoptosis induced by TNF, anti-Fas, UV irradiation, and serum withdrawal.     

Primary neurologic screening and motor coordination of Dstdt-J mutant mice (dystonia musculorum) with spinocerebellar atrophy

The autosomal recessive dystonia musculorum (Dst(dt-J)) mutation causes degenerative lesions of peripheral and central sensory pathways. A test battery of motor, sensory, postural, and autonomic functions was used to compare young control and homozygous Dst(dt-J) mice. The Dst(dt-J) mutants were severely impaired for muscle strength, limb coordination, and postural reflexes. As a result of a loss in motor control, the mutants were hypoactive in the open-field and fell quickly from the stationary beam. In sensory tests, the acoustic startle response was impaired, but not tactile reflexes and contact righting, attesting to preserved labyrinthine function and non-lemniscal pathways. Dst(dt-J) mutants were also distinguishable from controls on the basis of tremor, a paler skin, piloerection, and half-open eyes, as well as low body weight and fecal boli. Grooming episodes were less frequent in the mutants but without any reduction in grooming time. The neurologic screening battery delineated the functional integrity of some sensorimotor pathways in a spinocerebellar mutant whose severe phenotype prevents a more elaborate evaluation.     

Detection of C1 inhibitor (SERPING1/C1NH) mutations in exon 8 in patients with hereditary angioedema: evidence for 10 novel mutations

Hereditary angioedema (HAE) is caused by mutations in the C1 inhibitor gene (SERPING1, C1NH) and the result is C1 inhibitor deficiency, either in levels or function. We have searched exon 8 for mutations by direct sequencing and analyzed the rest of the exons by SSCP in 87 Spanish families affected by HAE. Out of 87 screened families, we have detected exon 8 mutations in 26. Among these, 17 different mutations were identified: 14 point mutations and 3 frameshift. Seven of the point mutations and the three frameshift were not previously reported. Mutations were: S438P; R444P; V451G; W460X; V468D; G471E; X479R; S417fsX427; I440fsX450; E429fsX450. The rest of the families presented previously reported mutations, 5 missense and two nonsense. In none of the 26 families was an additional change identified in the rest of the exons by SSCP, and, in 20 out of the 22 families with point mutation, we verified that the mutation did not affect a healthy relative. Seven of these families had no history of the disease, and in five of them we were able to verify that the progenitors did not have the mutation. Therefore, they were de novo mutations.     

Erratum: Detection of C1 inhibitor (SERPING1/C1NH) mutations in exon 8 in patients with hereditary angioedema: evidence for 10 novel mutations

The original article to which this Erratum refers was published in Human Mutation 20:405–406 Human Mutation (2002) 20(5) 405–406 The authors regret that there was an error in Table 2 on Page 4 of the original article. In patient DS, the nucleotide change 16838C>T is not correct. It should be 16838G>A, since this was the mutation at the antisense change.     

Thirteen novel mutations in the NR0B1 (DAX1) gene as cause of adrenal hypoplasia congenita

X-linked adrenal hypoplasia congenita (AHC) is a rare developmental disorder associated with primary adrenal insufficiency and combined primary and secondary male hypogonadism. It is caused by deletions or mutations of the NR0B1 (DAX1) gene encoding DAX1, an atypical orphan member of the nuclear receptor superfamily. The continuous molecular genetic analysis of male patients with primary adrenal insufficiency revealed 13 novel mutations within the coding region of the NR0B1 gene which are predicted to inactivate the DAX1 function. These were three nonsense mutations (c.312C>A, p.Cys104X, c.670C>T, p.Gln224X; and c.873G>A, p.Trp291X), five duplications (c.269_270dup, c.421_422dup, c.895_896dup, c.989dup, c.999_1000dup), and five deletions (c.483del, c.745_746del, c.734_740del, c.1092del, and c.1346del). All of the mutations resulted in a premature stop codon destroying the ligand binding domain of the predictive DAX1 protein.     

急性肾衰竭与胎肝Sca-1+细胞向肾脏细胞的分化

目的： 研究急性肾衰竭(ARF)对胎肝Sca-1+细胞向肾组织细胞分化频率的影响。 方法： 用磁性细胞分选(MACS)和PCR技术分离、鉴定小鼠雄性胎肝Sca-1+细胞；将2×104的雄性胎肝Sca-1+细胞输注给致死量射线照射(［60Co］，8 Gy)的同系雌性小鼠体内；8周后，将受体小鼠随机分为A、B和C 3组(A组：单纯辐射；B组：ARF和C组：ARF-Sca-1+)，用50%(V/V)的甘油(11.6 mL/kg)诱导B组和C组小鼠产生ARF；72 h后，将新制备的2×104的雄性胎肝Sca-1+细胞输注给C组小鼠。8周后处死全部实验小鼠，取肾脏固定制片；用Y染色体探针进行荧光原位杂交（fluorescence in situ hybridization， FISH），显微观察、摄像并用专业软件进行图像分析和数据处理。 结果： 在单纯辐射、ARF和ARF-Sca-1+ 3种模型小鼠的肾小管上皮、间质、肾小球和肾小球边缘等部位，均发现含Y染色体的细胞；在ARF和ARF-Sca-1+小鼠的肾组织切片中，分别发现成对和成环状排列的含Y染色体的细胞，有组成部分肾小管的趋势；胎肝Sca-1+细胞在单纯辐射、ARF和ARF-Sca-1+ 3种模型小鼠的肾组织切片中的分化频率分别为(1.65±0.18)%、(8.58±1.34)%和(18.13±1.91)%，后者与前者比较，差别有显著意义(P＜0.01)，显示分化频率伴随肾组织的损伤和再生而增加。 结论： 急性肾组织损伤和自然再生的生理微环境有助于促进胎肝Sca-1+细胞向肾组织细胞的分化。     

Low Ca2+ buffering in hypoglossal motoneurons of mutant SOD1 (G93A) mice

Mutations in the Cu/Zn superoxide dismutase (SOD1) gene are associated with amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder characterized by a selective degeneration of brainstem and spinal motoneurons. The pathomechanism of degeneration is still incompletely understood, but includes a disruption in cellular Ca2+ homeostasis. Here we report a quantitative microfluorometric analysis of the Ca2+ homeostasis in vulnerable hypoglossal motoneurons of neonatal mutant (G93A) SOD1 transgenic mice, a mouse model of human ALS. Ca2+ transient decay times (tau = 0.3 s), extrusion rates (gamma = 92 s(-1)) and exceptionally low intrinsic Ca2+ binding ratios (kappaS = 30) were found to be in the same range as compared to non-transgenic animals. Together with the previous observation of high Ca2+ binding ratios in ALS-resistant neurons (e.g. oculomotor), this supports the assumption that low Ca2+ buffering in vulnerable motoneurons represents a significant risk factor for degeneration. On the other hand, alterations in buffering properties by expression of mutant SOD1 are unlikely to be involved in disease initiation.