START domain proteins and the intracellular trafficking of cholesterol in steroidogenic cells

The intracellular trafficking of cholesterol in steroidogenic cells plays an important role in the regulation of hormone synthesis. Recent evidence indicates that a family of proteins related to the steroidogenic acute regulatory protein (StAR) perform critical functions in moving the sterol substrate to the mitochondrial inner membrane where the first committed step in steroid hormone synthesis occurs. StAR, the prototype of the family, is known to promote the translocation of cholesterol from the outer to the inner mitochondrial membrane. Mutations in StAR cause congenital lipoid adrenal hyperplasia, a cholesterol storage disorder in which synthesis of all gonadal and adrenocortical steroid hormones is severely impaired, and the cholesterol that is not efficiently moved into the mitochondria accumulates in cytoplasmic lipid droplets. The StAR-related lipid transfer (START) domain consists of an approximately 210 amino acid residue sequence that forms a compact alpha/beta structure, a helix-grip fold, with a hydrophobic tunnel that can accommodate a sterol molecule. START domains can bind sterol, facilitate the transfer of cholesterol from sterol-rich unilammelar liposomes to acceptor membranes, and stimulate steroidogenesis when expressed in cells co-expressing the cholesterol side-chain cleavage system or when added to isolated steroidogenic mitochondria. Sixteen human START domain proteins have been identified to date. Of these, StAR and MLN64 consist of one subfamily and newly described proteins named StarD4, StarD5, and StarD6 represent a closely related second subfamily. MLN64 is incorporated into the late endosomal compartment and is involved in the movement of cholesterol acquired from endocytosed LDL out of these vesicles. Expression of a dominant negative form of MLN64 causes accumulation of free cholesterol in lysosomes. The roles of StarD4, StarD5, and StarD6 in sterol movement remain to be determined. These genes have tissue-specific patterns of expression that may predict specialized roles.     

Histopathological features of the bronchi in severe bronchial asthma--a statistical analysis]

The aim of this study was to examine the histopathological features of the bronchi in patients with severe bronchial asthma. Seventy-four autopsy cases of death from severe bronchial asthma were analyzed statistically. The areas of the bronchial wall, smooth muscle, bronchial glands, basement membrane, and bronchial bore, were measured at the level of the subsegmental bronchi. Normal lungs from 34 autopsy cases without any respiratory pathology were used as controls. All of these areas but the last were significantly increased in severe bronchial asthma. The bronchial bore area was significantly decreased. Moreover, the above areas in low and moderate goblet cell hyperplasia cases were compared with those in high goblet cell hyperplasia cases. In the latter, the areas of the smooth muscle, bronchial glands and basement membrane were significantly elevated and those of the bronchial bore were significantly decreased. Finally, the areas of the bronchial bore, smooth muscle and bronchial glands were also compared between groups presenting with three different levels of basement membrane thickening, but no significant difference was noted. Further study to examine the precise morphological changes is needed to elucidate the characteristics of bronchi in severe bronchial asthma patients.     

CD3 down-regulating factor in sera and culture supernatants of leukaemic cells from patients with adult T cell leukaemia

Immunological abnormality of T lymphocytes in patients with adult T cell leukaemia (ATL) is characterized by abnormal expression of the 55 kD chain of the receptor for interleukin 2 (IL-2R/p55) (Tac), and the down-regulation of CD 3 expression. Using serum and culture supernatants of leukaemic cells from ATL patients (Group A) whose CD 3 expression was down-regulated and those (Group B) whose CD 3 was not low, the possible mechanism of CD 3 down-regulation on ATL cells was discussed. When PBMC from normal individuals were cultured with sera from ATL patients for 24 h, CD 3 expression revealed by mean fluorescent intensity (MFI) was down-regulated by sera from ATL patients in Group A (MFI: Pt 1 = 51.6 ± 4.5, Pt 2 = 48.0 ± 6.9, control = 96.5 ± 6.6), not by sera from patients in Group B (MFI: Pt 3 = 105.5 ± 7.9, Pt 4 = 102.5 ± 8.3, control = 96.5 ± 6.6). When normal PBMC were cultured with supernatants of leukaemic cells from ATL patients in Group A, this CD 3 down-regulating activity was also detected (MFI: Pt 1 = 78.0 ± 10.2, Pt 2 = 70.6 ± 8.7, control = 94.0 ± 6.6). By using gel-chromatography, the fractionated supernatants from ATL patients in Group A decreased CD 3 expression of normal PBMC significantly (MFI: Pt 1 = 22.9 ± 5.8, Pt 2 = 28.8 ± 7.4, control = 92.1 ± 9.6). This CD 3 down-regulating activity in fractionated supernatant was not inhibited by any lymphokine antibodies, anti-IL-1α antibody (Ab), anti-IL-1B Ab, anti-IL-2 Ab, anti-IL-3 Ab, anti-IL-4 Ab, anti-IL-6 Ab, anti-TNF-α Ab and anti-IFN-γ Ab. Any known cytokines (IL-1, IL-2, IL-3, IL-4, IL-6, TNF-α and IFN-γ) could not modulate CD 3 expression of normal PBMC. These findings suggested that there are novel factor(s) with CD 3 down-regulating activity in the serum and culture supernatant of ATL patient and those factor(s) are involved in progression of ATL.     

Indication of aortocoronary by-pass for coronary arterial obstruction due to Kawasaki disease

Summary Six patients with coronary arterial lesions due to Kawasaki disease underwent aortocoronary by-pass grafting at our institute. Before surgery, all of them had been closely monitored for some years by means of selective coronary arteriography, thallium myocardial imaging, electrocardiography (treadmill and/or Holter), and two-dimensional echo cardiography. Based on this experience, we propose the following guidelines as an indication for aortocoronary by-pass in such patients. First, the following three conditions should be satisfied: 1) The progress of coronary arterial lesions has been documented by serial selective coronary arteriography; 2) redistribution to the perfusion defect has been detected on the delayed image in myocardial imaging; 3) no coronary arterial lesions distal to the graft site have been detected by coronary angiography. When these three conditions are satisfied, at least one of the following conditions must apply: 1) Localized stenosis in the left main trunk has progressed to critical stenosis; 2) there is occlusion of two or more vessels; 3) collateral vessels connecting to the peripheral portion of an occluded coronary artery arise from the peripheral part of a vessel with progressive localized stenosis; 4) progressive localized stenosis or critical stenosis has developed in the left anterior descending artery, in addition to significant stenosis in the right coronary artery.     

Tofacitinib, a Janus Kinase Inhibitor Demonstrates Efficacy in an IL-15 Transgenic Mouse Model that Recapitulates Pathologic Manifestations of Celiac Disease

Celiac disease (CD) is an immune-mediated, inflammatory disorder of the small intestines with a defined genetic etiological component associated with the expression of HLA-DQ2 and/or HLA-DQ8 haplotypes. The dietary consumption of gluten-rich cereals triggers a gluten-specific immune response in genetically susceptible individuals leading to a spectrum of clinical manifestations ranging from an inapparent subclinical disease, to overt enteropathy that can in some individuals progress to enteropathy-associated T cell lymphoma (EATL). The tissue-destructive pathologic process of CD is driven by activated NK-like intraepithelial CD8⁺ lymphocytes and the proinflammatory cytokine IL-15 has emerged to be pivotal in orchestrating this perpetual tissue destruction and inflammation. Moreover, transgenic mice that over-express human IL-15 from an enterocyte-specific promoter (T3^b-hIL-15 Tg) recapitulate many of the disease-defining T and B cell-mediated pathologic features of CD, further supporting the evolving consensus that IL-15 represents a valuable target in devising therapeutic interventions against the form of the disease that is especially refractory to gluten-free diet. In the present study, we evaluated the potential efficacy of tofacitinib, a pan-JAK inhibitor that abrogates IL-15 signaling, as a therapeutic modality against CD using T3^b-hIL-15 Tg mice. We demonstrate that tofacitinib therapy leads to a lasting reversal of pathologic manifestations in the treated mice, thereby highlighting the potential value of tofacitininb as a therapeutic modality against refractory CD for which no effective therapy exists currently. Additionally, the visceral adiposity observed in the tofacitinib-treated mice underscores the importance of continued evaluation of the drug’s impact on the lipid metabolism.     

Effects of dextran sulfates on the acute infection and growth stages of Toxoplasma gondii

Toxoplasma gondii is one of the most prevalent parasites, causing toxoplasmosis in various warm-blooded animals, including humans. Because of the broad range of hosts susceptible to T. gondii, it had been postulated that a universal component of the host cell surface, such as glycosaminoglycans (GAGs), may act as a receptor for T. gondii infection. Carruthers et al. (Infect Immun 68:4005–4011, 2000) showed that soluble GAGs have also been shown to disrupt parasite binding to human fibroblasts. Therefore, we investigated the inhibitory effect of GAGs and their analogue dextran sulfate (DS) on T. gondii infection. For up to 24 h of incubation after inoculation of T. gondii, the inhibitory effect of GAGs on T. gondii infection and growth inside the host cell was weak. In contrast, DS markedly inhibited T. gondii infection. Moreover, low molecular weight DS particularly slowed the growth of T. gondii inside host cells. DS10 (dextran sulfate MW 10 kDa) was the most effective agent in these in vitro experiments and was therefore tested for its inhibitory effects in animal experiments; infection inhibition by DS10 was confirmed under these in vivo conditions. In this report, we showed that DSs, especially DS10, have the potential of a new type of drug for toxoplasmosis.     

Mutation Analysis of the IL36RN Gene in 14 Japanese Patients with Generalized Pustular Psoriasis

Generalized pustular psoriasis (GPP) is a rare, potentially life threatening, and aggressive form of psoriasis, which is characterized by sudden onset with repeated episodic skin inflammation leading to pustule formation. Familial GPP is known to be caused by recessively inherited mutations in the IL36RN gene, which encodes interleukin 36 receptor antagonist (IL‐36Ra). In this article, we performed mutation analysis of the IL36RN gene in 14 Japanese patients with GPP, and identified mutations in two of these patients analyzed. One patient was compound heterozygous for mutations c.115+6T>C and c.368C>G (p.Thr123Arg), whereas the other carried compound heterozygous mutations c.28C>T (p.Arg10*) and c.115+6T>C in the IL36RN gene. Expression studies using total RNA from the patients’ skin revealed that the mutation c.115+6T>C resulted in skipping of exon 3, leading to a frameshift and a premature termination codon (p.Arg10Argfs*1). The protein structure analysis suggested that the missense mutation p.Thr123Arg caused misfolding and instability of IL‐36Ra protein. In vitro studies in cultured cells showed impaired expression of the p.Thr123Arg mutant IL‐36Ra protein, which failed to antagonize the IL‐36 signaling pathway. Our data further underscore the critical role of IL36RN in pathogenesis of GPP.