Chediak-Higashi Syndrome Mice Research Articles

A thiol proteinase inhibitor, E-64-d, corrects the abnormalities in concanavalin A cap formation and the lysosomal enzyme activity in leucocytes from patients with Chediak-Higashi syndrome by reversing the down-regulated protein kinase C activity.

We have reported previously that the abnormally down-regulated protein kinase C (PKC) causes cellular dysfunction observed in natural killer (NK) cells, polymorphonuclear leucocytes (PMNs) and fibroblasts from beige mouse, an animal model of Chediak-Higashi syndrome (CHS). Here we show that the abnormal down-regulation of PKC activity also occurs in Epstein-Barr (EB) virus-transformed cell lines from CHS patients. When CHS cell lines were stimulated with concanavalin A (Con A) for 20 min, the membrane-bound PKC activity declined markedly, whereas that in control cell lines increased. We found that E-64-d, which protects PKC from calpain-mediated proteolysis, reversed the declined PKC activity and corrected the increased Con A cap formation to almost normal levels in CHS cell lines. We confirmed that the dysregulation of PKC activity also occurred in peripheral blood mononuclear leucocytes (PBMC) from CHS patients and that E-64-d corrected both the declined PKC activity and increased Con A cap formation. E-64-d also corrected the reduced lysosomal elastase and cathepsin G activity in CHS cell lines. In contrast, chelerythrin, a specific inhibitor of PKC, and C2-ceramide, which promotes PKC breakdown induced by calpain, increased Con A cap formation and inhibited both elastase and cathepsin G activity in normal cell lines. Moreover, we found that ceramide production in CHS cell lines increased significantly after Con A stimulation, which coincides with our previous observation in fibroblasts from CHS mice. These results suggest an association between ceramide-induced PKC down-regulation and the cellular dysfunctions in CHS.

Interspecific genetic complementation analysis with fibroblasts from humans and four species of animals with Chediak-Higashi syndrome.

Although the autosomal recessive disease Chediak-Higashi syndrome (CHS) has been described in humans, cats, mink, cattle, mice, killer whales, blue foxes, and silver foxes, and these conditions appear quite similar, no direct evidence of the homology of this disease in the various species has been presented. To determine if CHS in humans, cats, mink, cattle, and mice is due to a mutant gene at the homologous genetic locus in each species, or alternatively, if these are merely similar syndromes, genetic complementation analysis after interspecific somatic cell (fibroblast) hybridization was performed. "Paracrystal" formation was the criterion used for the determination of complementation. The initial studies in this report were designed to characterize paracrystal formation in control and CHS fibroblasts of these five species. Most of the control fibroblasts from each species (91-96.6%) formed paracrystals upon incubation with 25 micrograms/ml of the microtubule depolymerizing agent vinblastine sulfate. A significantly (P less than 0.05) smaller percentage of the CHS fibroblasts formed paracrystals after the same incubation (except CHS mice, with 90.2% paracrystals). It was found that 52% of the human CHS fibroblasts, 60% of cat CHS fibroblasts, 47% of mink CHS fibroblasts, and 53.8% of cow CHS fibroblasts formed paracrystals. For genetic complementation analysis, human CHS fibroblasts were fused to cat, mink, cow, or mouse CHS fibroblasts with polyethylene glycol. Control fusions were human CHS fibroblasts fused with human, cat, mink, cow, and mouse normal fibroblasts. The results of complementation analysis after the fusion of human CHS with cow CHS and human CHS with mouse CHS fibroblasts were inconclusive. A lack of complementation of human CHS with cat CHS and human CHS with mink CHS fibroblasts indicates that the disease is homologous in these species.

A comparative study of the lesions in cultured fibroblasts of humans and four species of animals with Chediak‐Higashi syndrome

The Chediak-Higashi syndrome (CHS) is an autosomal recessive genetic disease of humans, and clinically similar diseases occur in cats, mink, cattle, mice, killer whales, blue foxes, and silver foxes. It is characterized by incomplete albinism, increased susceptibility to infection, and the most distinctive hallmark, the presence of enlarged cytoplasmic granules in many cell types. The acid phosphatase-positive granules, lysosomes, of fibroblasts from control and CHS humans, cats, mink, cattle, and mice were examined. These studies represent the initial characterization of the lesions in fibroblasts of CHS cats, mink, and cattle. Fibroblasts from each species and genotype were stained histochemically for acid phosphatase, and morphometric analysis of the distribution of acid phosphatase-positive granules was performed. The lysosomes in the CHS fibroblasts tended to be restricted to the perinuclear area of the cytoplasm, whereas the lysosomes in the normal fibroblasts were generally more widely distributed in the cytoplasm. The lysosomes in the CHS fibroblasts of all species examined were also more enlarged and heterogeneous than those in the control fibroblasts.

Ocular melanin pigmentation anomalies in cats, cattle, mink, and mice with Chediak-Higashi syndrome: histologic observations.

The Chediak-Higashi syndrome (CHS) is a hereditary disorder of man, with the homologous condition reported in five animal species. Multiple defects, including oculocutaneous hypopigmentation, are present in individuals with this syndrome. Giant cytoplasmic granules, including melanosomes and lysosomes, are characteristic. In this study, eyes from CHS affected and control cats, cattle, mink, and mice were examined histologically to determine: 1) degree of pigmentation; 2) structure and distribution of melanin granules; and 3) morphology of cells and tissues containing melanin. The CHS cattle were found to be the most ocularly hypopigmented species, whereas CHS mouse eyes contained considerably more melanin than those of the other species. Melanin granules of abnormal sizes and shapes were present in neuroepithelial and uveal tissues of CHS animals of all four species. Depigmentation apparently had occurred in the CHS eyes, since less melanin was present in eyes of old CHS animals of each species than was present in eyes of young animals. In addition, melanin containing macrophages were common in CHS eyes, and the numbers of melanocytes and pigmented epithelial cells were decreased in older CHS eyes.

Natural killer cell activity in fawn-hooded rats.

Fawn-hooded (FH) rats were shown to lack the genetically conditioned defect of natural killer (NK) activity hypothesized to be present by analogy with the Chediak-Higashi syndrome (CHS) in mice and human beings. In 4-h 51Cr release assays, splenic NK cells from FH rats killed YAC-1, RL male l and G1-TC tumor targets without deficiency based upon comparison with cells from BD-IV, BD-IX and NBR inbred rat strains. Progeny of BD X FH F1 rats backcrossed to FH failed to reveal a correlation of reduced NK activity and dilute coat color. From these, and other data presented, it is concluded that despite similarities in coat color dilution and platelet storage pool deficiency. FH rats do not closely resemble CHS mice or human beings in having deficient NK activity and cannot be considered the rat homolog of the CHS.

Efficacy of Ascorbic Acid in Chediak-Higashi Syndrome (CHS): Studies in Humans and Mice

The efficacy of ascorbic acid therapy in Chediak-Higashi syndrome (CHS) was assessed in two humans and in the mouse model of this disease. Ascorbic acid (6 g/day) was given for 8 mo to two brothers (26 and 27 yr old) with CHS. The therapy had no effect on the clinical course of these patients and no change in their complete blood count or abnormal leukocyte morphology (giant lysosomes). In addition, the leukocyte dysfunction seen in this disease was not improved by ascorbic acid; skin window responses, chemotaxis, and bactericidal activity remained abnormal and there was no change in lymphocyte function. No abnormality of leukocyte cAMP or cGMP was seen in our patients, and no changes in basal cyclic nucleotides occurred during ascorbic acid therapy. In other studies high doses of intraperitoneal ascorbic acid (20 mg/mouse) prolonged the survival of CHS mice from lethal infection with Candida albicans, although the survival of CHS treated mice was not as good as that of saline-treated controls. Ascorbic acid also improved polymorphonuclear leukocyte chemotaxis and bactericidal activity for Staphylococcus aureus. Despite the improved function there was no change in the morphology of CHS mouse leukocytes after ascorbic acid therapy. In addition, we found no abnormality of basal leukocyte cyclic nucleotide levels and no change in basal cyclic nucleotides after ascorbic acid therapy. These data indicate that although ascorbic acid may have a beneficial effect in mice with CHS, patients with CHS may not respond in a similar manner.

Infection and immunoglobulin concentrations in Chediak-Higashi mice.

The Chediak-Higashi syndrome (CHS) has been reported in man, cattle, mink, and mice. CHS humans and cattle have an increased incidence of pyogenic infections, whereas CHS mink are more susceptible to Aleutian disease. Age- and sex-matched groups of CHS mice (mutant strain) and C57 Bl/6N (parent strain) were challenged with Candida albicans, Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus intravenously and Streptococcus pneumoniae intraperitoneally. A significant increase (P < 0.001) in mortality rate for the CHS mice was demonstrated with all five challenge organisms. Heterozygous mice challenged with C. albicans had a mortality rate essentially the same as C57 Bl/6N mice. The serum immunoglobulin concentrations of CHS mice were found to be the same or greater than the control or heterozygous mice. CHS mice have an increased susceptibility to pyogenic infections, which is not due to immunoglobulin deficiency. These mice may provide a useful laboratory model for the study of increased susceptibility to infection.

Granulocyte Function in the Chediak-Higashi Syndrome of Mice

Abstract Granulocyte function was evaluated using peritoneal exudate granulocytes from a strain of beige mice with the Chediak-Higashi syndrome (CHS). Defective granulocyte chemotaxis of CHS cells (43% normal) was documented. There was no abnormality in the ability of CHS serum to function as a chemotactic stimulus. Phagocytosis of 14C-labeled Staphylococcus aureus by CHS granulocytes was normal. However, there was reduced bactericidal activity of S. aureus and group D streptococcus by CHS cells through 90 min of incubation. The bactericidal defect was most pronounced at early time periods and was related to impaired intracellular killing. These defects of CHS mice granulocytes were analogous to those reported in man and it is concluded that the CHS mouse is a most convenient and representative model of the CHS of man.