Modeling neural crest induction, melanocyte specification, and disease-related pigmentation defects in hESCs and patient-specific iPSCs

Melanocytes are pigment-producing cells of neural crest (NC) origin that are responsible for protecting the skin against UV irradiation. Pluripotent stem cell (PSC) technology offers a promising approach for studying human melanocyte development and disease. Here, we report that timed exposure to activators of WNT, BMP, and EDN3 signaling triggers the sequential induction of NC and melanocyte precursor fates under dual-SMAD-inhibition conditions. Using a SOX10::GFP human embryonic stem cell (hESC) reporter line, we demonstrate that the temporal onset of WNT activation is particularly critical for human NC induction. Subsequent maturation of hESC-derived melanocytes yields pure populations that match the molecular and functional properties of adult melanocytes. Melanocytes from Hermansky-Pudlak syndrome and Chediak-Higashi syndrome patient-specific induced PSCs (iPSCs) faithfully reproduce the ultrastructural features of disease-associated pigmentation defects. Our data define a highly specific requirement for WNT signaling during NC induction and enable the generation of pure populations of human iPSC-derived melanocytes for faithful modeling of pigmentation disorders.

[Screening for cytotoxic defects with flow cytometric detection of CD107α on natural killer cells and cytotoxic lymphocyte cells]

OBJECTIVE

To establish a novel flow cytometry-based assay for measuring the expression of lysosomal-associated membrane protein 1 (LAMP-1, CD107α) on the cell surface of natural killer (NK) cells and cytotoxic T lymphocyte (CTL) and evaluate the screening value of this assay for cytotoxic defects-related diseases such as familial hemophagocytic lymphopro-liferative (FHL) syndrome.

METHOD

Three suspected Chediak-Higashi Syndrome (CHS) patients, three suspected FHL patients and 10 healthy children were enrolled in the study from October 2010 to June 2011. Their PBMCs were separated and activated overnight with IL-2. After the granule release of NK cells activated by phytohemagglutinin (PHA) and CD8+T cells by anti-CD3, the CD107α expression were analyzed by flow cytometry. The peripheral blood DNA and RNA of the patients were extracted to analyze the pathogenic genes via DNA-PCR/RT-PCR and direct sequencing.

RESULT

The CD107α expression on CTL in the ten healthy children significantly increased after activation by anti-CD3 [(0.18 ± 0.07)% vs. (4.47 ± 2.36)%, P < 0.05] and NK cells after activation by PHA [(0.27 ± 0.07)% vs. (5.80 ± 2.83)%, P < 0.05]. The frequency of CD107α-expression NK cells in three suspected CHS after activation was significantly elevated when compared with the healthy control [0.5%, 0.6% vs. (5.80 ± 2.83)%] except patient 2. After the anti-CD3 activation, the frequency of CD107α expression on CTL cells also showed no significant difference [0.3%, 0.9%, 0.2% vs. (4.47 ± 2.36)%] in three patients. All of their mean fluorescence intensity (MFI) showed the same trend. Patient 1 and 3 were identified to have LYST mutations (Patient 1: c.5411-5414 del TTTC, L1741fsX1758 and c.7975 C > T, R2596X; Patient 3: c.4863G > A, R1563H and c.5392-5393delAA, E1739fsX1756). There was no mutation identified in the LYST gene for patient 2. CD107α expression of NK cells and CTL in the suspected FHL patients and in mirror of these findings, no underlying gene variation of PRF, MUNC13-4 and STX11 were identified.

CONCLUSION

We developed a method to quantitatively assess cytotoxicity of the NK cells and CTL by measuring the expression of CD107α on the cell membrane, which appeared to be an effective and rapid screening test for cytotoxic defects-related diseases such as FHL and other HLH secondary to primary immunodeficiency.

Identification of proteins in the ceroid-like autofluorescent aggregates from liver lysosomes of Beige, a mouse model for human Chediak-Higashi syndrome

Chediak-Higashi syndrome is characterized by oculocutaneous albinism, a bleeding tendency and severe recurrent infections. Age-dependent formations of autofluorescent ceroid-like substances have been noted in a variety of tissues. In this study, we isolated an autofluorescent ceroid-like aggregate from purified Beige mouse liver lysosomes and analyzed the composition of the aggregate by ion trap mass-spectrometry. In addition to lysosomal proteins, this aggregate contains proteins normally localized in the ER, mitochondria, peroxisomes, and the cytosol. Bip, a luminal ER protein was abundant in lysosomal ceroid. The ER, mitochondria, and cytosol proteins could arise in lysosomes through stimulation of autophagy, but we found no differences between normal and CHS fibroblasts in the degree of lysosomal acidity and in the level of conversion of soluble microtubular-associated protein 1 light chain 3 type I to membrane-associated type II, an accepted probe for hyper-autophagy suggesting that ceroid formation is unlikely to arise via this mechanism.

A LYST/beige homolog is involved in biogenesis of Dictyostelium secretory lysosomes

Chediak-Higashi syndrome (CHS) is characterized at the cellular level by a defect in the ability of cells to secrete lysosomes. However, the precise step affected in the secretion process is unclear. We characterized Dictyostelium discoideum cells containing a mutation in lvsB, the homolog of the human gene (LYST) involved in CHS. As observed in mammalian cells, secretion of lysosome-derived compartments was affected in lvsB mutant cells. This defect was mirrored by a decrease in the number of fusion-competent post-lysosomal compartments, which in Dictyostelium can be clearly distinguished from lysosomes. In addition, the transfer of endocytosed particles from lysosomes to post lysosomes was strongly diminished in lvsB mutant cells compared with the wild type. These results suggest that LvsB is primarily involved in transport from lysosomes to post lysosomes, and thus plays a critical role in the maturation of lysosomes into fusion-competent post-lysosomal compartments.

Acute myeloid leukemia with pseudo-Chèdiak-Higashi anomaly exhibits a specific immunophenotype with CD2 expression

Acute myeloid leukemia (AML) with pseudo-Chèdiak-Higashi (PCH) anomaly is a rare morphologic entity. We characterized 5 cases by multiparameter flow cytometry and found that in all cases, the blasts aberrantly expressed CD2, a pan-T cell-associated marker, in addition to their myeloid-associated markers. In contrast, CD2 was expressed in only 25 (17.9%) of 140 cases of newly diagnosed AML without PCH anomaly. CD2 expression correlated strongly with AML with PCH anomaly (P < .01), suggesting a link between a specific immunophenotypic marker, CD2, and AML with PCH anomaly.

Defective lysosomal exocytosis and plasma membrane repair in Chediak-Higashi/beige cells

Plasma membrane resealing is a Ca(2+)-dependent process that involves the exocytosis of intracellular vesicles next to the wound site. Recent studies revealed that conventional lysosomes behave as Ca(2+)-regulated secretory compartments and play a central role in membrane resealing. These findings raised the possibility that the complex pathology of lysosomal diseases might also include defects in plasma membrane repair. Here, we investigated the capacity for lysosomal exocytosis and membrane resealing of fibroblasts derived from Chediak-Higashi syndrome (CHS) patients, or from beige-J mice. By using a sensitive electroporation/fluorescence-activated cell sorter-based assay, we show that lysosomal exocytosis triggered by membrane wounding is impaired in both human Chediak-Higashi and mouse beige-J fibroblasts. Lysosomal exocytosis increased when the normal size of lysosomes was restored in beige-J cells by expression of the CHS/Beige protein. A similar effect was seen when the lysosomal enlargement in beige-J cells was reversed by treatment with E64d. In addition, the survival of Chediak-Higashi and beige-J fibroblasts after wounding was reduced, indicating that impaired lysosomal exocytosis inhibits membrane resealing in these mutant cells. Thus, the severe symptoms exhibited by CHS patients may also include defects in the ability of cells to repair plasma membrane lesions.

Crystal Structure of the PH−BEACH Domains of Human LRBA/BGL†

The beige and Chediak-Higashi syndrome (BEACH) domain defines a large family of eukaryotic proteins that have diverse cellular functions in vesicle trafficking, membrane dynamics, and receptor signaling. The domain is the only module that is highly conserved among all of these proteins, but the exact functions of this domain and the molecular basis for its actions are currently unknown. Our previous studies showed that the BEACH domain is preceded by a novel, weakly conserved pleckstrin homology (PH) domain. We report here the crystal structure at 2.4 A resolution of the PH-BEACH domain of human LRBA/BGL. The PH domain has the same backbone fold as canonical PH domains, despite sharing no sequence homology with them. However, our binding assays demonstrate that the PH domain in the BEACH proteins cannot bind phospholipids. The BEACH domain contains a core of several partially extended peptide segments that is flanked by helices on both sides. The structure suggests intimate association between the PH and the BEACH domains, and surface plasmon resonance studies confirm that the two domains of the protein FAN have high affinity for each other, with a K(d) of 120 nM.

Crystal structure of the BEACH domain reveals an unusual fold and extensive association with a novel PH domain

The BEACH domain is highly conserved in a large family of eukaryotic proteins, and is crucial for their functions in vesicle trafficking, membrane dynamics and receptor signaling. However, it does not share any sequence homology with other proteins. Here we report the crystal structure at 2.9 A resolution of the BEACH domain of human neurobeachin. It shows that the BEACH domain has a new and unusual polypeptide backbone fold, as the peptide segments in its core do not assume regular secondary structures. Unexpectedly, the structure also reveals that the BEACH domain is in extensive association with a novel, weakly conserved pleckstrin-homology (PH) domain. Consistent with the structural analysis, biochemical studies show that the PH and BEACH domains have strong interactions, suggesting they may function as a single unit. Functional studies in intact cells demonstrate the requirement of both the PH and the BEACH domains for activity. A prominent groove at the interface between the two domains may be used to recruit their binding partners.

Chediak-Higashi Syndrome: a rare disorder of lysosomes and lysosome related organelles

Chediak-Higashi Syndrome (CHS) is a rare autosomal recessive disorder characterized by severe immunologic defects including recurrent bacterial infections, impaired chemotaxis and abnormal natural killer (NK) cell function. Patients with this syndrome exhibit other symptoms such as an associated lymphoproliferative syndrome, bleeding tendencies, partial albinism and peripheral neuropathies. The classic diagnostic feature of CHS is the presence of huge lysosomes and cytoplasmic granules within cells. Similar defects are found in other mammals, the most well studied being the beige mouse and Aleutian mink. A positional cloning approach resulted in the identification of the Beige gene on chromosome 13 in mice and the CHS1/LYST gene on chromosome 1 in humans. The protein encoded by this gene is 3801 amino acids and is highly conserved throughout evolution. The identification of CHS1/Beige has defined a family of genes containing a common BEACH motif. The function of these proteins in vesicular trafficking remains unknown.

Alterations in erythrocyte membrane lipid and fatty acid composition in Chediak-Higashi syndrome

Chediak-Higashi syndrome (CHS) is an autosomal recessive disease characterized by the presence of abnormally large cytoplasmic organelles in all body granule producing cells. The molecular mechanism for this disease is still unknown. Functional disorders in membrane-related processes have been reported. Erythrocyte membranes from four CHS patients and 15 relatives including obligatory heterozygous were studied to examine potential alterations in the lipid and fatty acid profile of erythrocyte membranes associated with this syndrome. Plasma concentrations of cholesterol, triglycerides, phospholipids, and apolipoproteins AI and B100, and the lipid components of very low-, intermediate-, low- and high-density lipoproteins were also determined. CHS erythrocyte membranes were found to be enriched with lipids in relation to protein and to show: (1) an increase in cholesterol and choline-containing phospholipids (sphingomyelin and phosphatidylcholine) that predominate in the outer monolayer, which is higher than the increase in phosphatidylserine and phosphatidylethanolamine, that are chiefly limited to the inner monolayer in normal red blood cells; (2) a relative palmitic acid and saturated fatty acid increase and arachidonic acid and unsaturated fatty acid decrease, this resulting in a lower unsaturation index than controls. Changes in CHS erythrocyte membrane lipids seem to be unrelated to serum lipid disorders as plasma lipid and apolipoprotein concentrations were apparently in the normal range, with the exception of a modest hypertriglyceridemia in patients and relatives and a decreased concentration of HDL cholesterol in patients. These findings indicate that CHS erythrocyte membranes contain an abnormal lipid matrix with which membrane proteins are defectively associated. The anomalous CHS membrane composition can be explained on the postulated effects of the CHS1/Lyst gene.

Analysis of the lysosomal storage disease Chediak-Higashi syndrome

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder of human, mouse (beige) and other mammalian species. The same genetic defect was found to result in the disease in all species identified, permitting a positional cloning approach using the mouse model beige to identify the responsible gene. The CHS gene was cloned and mutations identified in affected species. This review discusses the clinical features of CHS contrasting features seen in similar syndromes. The possible functions of the protein encoded by the CHS/beige gene are discussed, along with the alterations in cellular physiology seen in mutant cells.

Protein truncation test of LYST reveals heterogenous mutations in patients with Chediak-Higashi syndrome

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder in which an immune deficiency occurs in association with pigmentation abnormalities. Most patients who do not undergo bone marrow transplantation die of a lymphoproliferative syndrome, though some patients with CHS have a relatively milder clinical course of the disease. The large size of the LYST gene, defective in CHS, has made it difficult to screen for mutations in a large number of patients. Only 8 mutations have been identified so far, and all lead to a truncated LYST protein. We conducted protein truncation tests on this gene in 8 patients with CHS. Different LYST mutations were identified in all subjects through this approach, strengthening the observation of a high frequency of truncated LYST proteins as the genetic cause of CHS.

Clinical, molecular, and cell biological aspects of Chediak-Higashi syndrome

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by variable degrees of oculocutaneous albinism, easy bruisability, and bleeding as a result of deficient platelet dense bodies, and recurrent infections, with neutropenia, impaired chemotaxis and bactericidal activity, and abnormal NK cell function. Neurologic involvement is variable, but often includes peripheral neuropathy. Most patients also undergo an "accelerated phase," which is a nonmalignant lymphohistiocytic infiltration of multiple organs resembling lymphoma. Death often occurs in the first decade from infection, bleeding, or development of the accelerated phase. The hallmark of CHS is the presence of huge cytoplasmic granules in circulating granulocytes and many other cell types. These granules are peroxidase-positive and contain lysosomal enzymes, suggesting that they are giant lysosomes or, in the case of melanocytes, giant melanosomes. The underlying defect in CHS remains elusive, but the disorder can be considered a model for defects in vesicle formation, fusion, or trafficking. Because the beige mouse demonstrates many characteristics similar to those of human CHS patients, including dilution of coat color, recurrent infections, and the presence of giant granules, it is considered the animal homologue of CHS. The beige gene, Lyst, was mapped and sequenced in 1996, prompting identification of the human LYST gene on chromosome 1q42. Lyst and LYST show 86.5% sequence homology. LYST encodes a 429 kDa protein with a function that remains unknown, but the source of extensive speculation among students of cell biology.

Distinguishing between the catalytic potential and apparent expression of tyrosinase activities

Assays were developed to investigate the catalytic potential and apparent expression of tyrosinase activities. Tyrosine hydroxylase activity determined with cell lysates (in vitro), entire fixed cells (postfixation), or intact living cells (in situ), and 3,4-dihydroxyphenylalanine oxidase assayed spectrophotometrically or by 3,4-dihydroxyphenylalanine staining on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, demonstrated the following results: 1) The in situ assay displayed reduced tyrosine hydroxylase activity in all three tyrosinase-positive oculocutaneous albino (OCA) lines except for Chediak-Higashi Syndrome melanocytes, which displayed normal activity; 2) The in vitro assay had comparable activity of tyrosinase-positive OCA melanocytes as controls, except for one tyrosinase-positive OCA cell line, which demonstrated increased activity; 3) The postfixation assay, compared with the in situ assay, had elevated activity (ie. normalization) of tyrosinase in OCA cells but reduced activity in controls; 4) The spectrophotometric assay for 3,4-dihydroxyphenylalanine oxidase activity correlated very well with the tyrosine hydroxylase activity determined by the in vitro assay; 5) sodium dodecyl sulfate-polyacrylamide gel electrophoresis of melanocyte lysates either stained with 3,4-dihydroxyphenylalanine or immunoblotted with anti-tyrosinase detected abnormal tyrosinase bands in the Chediak-Higashi Syndrome and one line of tyrosinase positive OCA melanocytes, and both lines had release of tyrosinase into the growth media. In conclusion, the selection and combination of these tyrosinase assays would be informative for differentiation and characterization of human albinism.

On the analysis of the pathophysiology of Chediak-Higashi syndrome. Defects expressed by cultured melanocytes

BACKGROUND

The Chediak-Higashi syndrome (CHS) is a disorder that affects the synthesis and/or maintenance of storage/secretory granules in various types of cells. Lysosomes of leukocytes and fibroblasts, dense bodies of platelets, azurophilic granules of neutrophils and melanosomes of melanocytes are generally larger in size and irregular in morphology, indicating that a common pathway in storage organellogenesis is affected in patients with CHS.

EXPERIMENTAL DESIGN

A pure line of melanocytes has been established using a 2 cm2 shave biopsy from a child with CHS. This 4-week-old male patient had oculocutaneous albinism and expressed neutropenia, impaired platelet function, and no natural killer cell activity. The cultured CHS melanocytes were analyzed for cell biological and biochemical aberrancies.

RESULTS

Cultured melanocytes demonstrated some large and/or complexed melanosomes that resembled those observed in melanocytes from ultrastructural sections of the biopsy. Cytoplasmic localization of tyrosinase, tyrosinase-related protein-1 and granulophysin (a 40 kilodalton membrane protein originally identified as a component in dense bodies of platelets) demonstrated a prominent perinuclear accumulation. The basal synthesis of melanin and the activity levels of tyrosine hydroxylase, dihydroxyphenylalanine (DOPA) oxidase, or DOPAchrome tautomerase were comparable to control Caucasian melanocytes in culture. However, melanin synthesis as well as the catalytic activities of tyrosinase were not dramatically upregulated in CHS melanocytes by the addition of isobutyl methylxanthine and cholera toxin in the growth medium when parameters were assayed in cell lysates. In contrast, when assays were performed using live cells, tyrosine hydroxylase demonstrated dramatic upregulation. Medium conditioned by CHS melanocytes demonstrated phenylthiourea-inhibitable tyrosinase activity. Melanocyte lysates and conditioned medium analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and DOPA staining showed an extra, approximately 100 kilodalton soluble protein band with DOPA positivity and tyrosinase immunoreactivity. In addition to tyrosinase, one of three lysosomal enzymes assayed (beta-glucuronidase) was aberrantly secreted into the medium.

CONCLUSIONS

These results demonstrate that melanocytes cultured from CHS express a defect in the structure and/or function of the melanosome and abnormal trafficking of some cellular proteins.

A histochemical and electron microscopic study of skeletal muscle in an adult case of Chédiak-Higashi syndrome

To clarify the muscle pathology findings of a 39-year-old female Chédiak-Higashi syndrome (CHS) case with diffuse limb muscle atrophy, histochemical and electron microscopic studies were performed. In addition to neurogenic muscle atrophy due to the peripheral neuropathy, the most striking change seen by light microscopy was the widespread appearance of acid phosphatase-positive granules in many normal-looking muscle fibers. Coincident with the histochemical findings, electron microscopy showed many autophagic vacuoles containing glycogen particles and membranous structures in almost all muscle fibers. Although further studies are necessary, diffuse distribution of acid phosphatase-positive granules (autophagic vacuoles) in the skeletal muscle may reflect one of the generalized lysosomal abnormalities in CHS.

Studies of adenine nucleotide biochemistry in the Chediak-Higashi syndrome

The Chediak-Higashi syndrome (CHS) is an inherited disorder of humans and of several animal species, characterized by partial albinism, pseudohemophilia, increased susceptibility to disease, and large inclusions in all granule-forming cells. In this study, various parameters of adenine nucleotide biochemistry were examined in beige mouse kidney tissue and in peripheral blood leukocytes from CHS mink. There were no differences in the total protein content, total ATPase activity or the magnesium (Mg2+) ATPase or the sodium-potassium (Na(+)-K+) ATPase activities, the concentrations of ATP, ADP, and AMP, or the adenylate energy charge (AEC) in kidney extracts from beige and normal mice. In studies of leukocytes, there were no differences in the concentrations of ATP, ADP, AMP, and cAMP or the AECs in total leukocyte preparations and in extracts from granulocytes or nongranulocytes. These results can be explained by any one of several hypotheses: no storage pool of adenine nucleotides exists in the tissues examined; or the alleged storage pool is not affected by CHS; or the quantity of nucleotides in the alleged storage pool is too minute to be evaluated by current techniques; or the CHS defect might cause a shift from the storage pool to the metabolic pool.

Chediak-Higashi lymphoblastoid cell lines: granule characteristics and expression of lysosome-associated membrane proteins

Chediak-Higashi syndrome (CHS) is characterized morphologically by the presence of giant lysosomal granules resulting from the dysregulated fusion of primary lysosomes. Lysosome-associated membrane proteins comprise a family of highly glycosylated proteins which are postulated to facilitate many aspects of normal lysosomal function. In this study, Epstein-Barr virus-transformed lymphoblastoid cell lines derived from a patient with CHS were analyzed for the presence of giant granules and the expression of the lysosome-associated membrane proteins lamp1 and lamp2. Giant myeloperoxidase positive granules typical of CHS, which had a complex structure when examined by electron microscopy, could be demonstrated in the lymphoblastoid cell lines. In situ immunofluorescence with antibodies directed against lamp1 and lamp2 demonstrated abundant expression of each of these proteins in the giant CHS granules. Lack of expression of lysosomal cathepsin G in these granules was also noted. These observations suggest that the lymphoblastoid cell lines provide a convenient model for the study of Chediak-Higashi granules and the lysosome-associated membrane proteins and provide additional evidence that CHS is a "lysosomal" disease. Further study will be necessary to delineate whether the function of these membrane proteins is altered in Chediak-Higashi syndrome.

[Electron microscopic cytochemistry of pseudo-Chediak-Higashi granules in 5 cases of AML]

Blasts from 5 cases of AML with pseudo-Chediak-Higashi granules were examined ultrastructurally and histocytochemically using peroxidase, acid phosphatase, high iron diamine (HID) and periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) stainings. Pseudo-Chediak-Higashi granules, which appeared as vacuole-like inclusions by light microscopy, generally contained electron-lucent materials. All pseudo-Chediak-Higashi granules were, positive for peroxidase but some were negative for acid phosphatase. Pseudo-Chediak-Higashi granules were HID positive, indicating that they contained sulfated glycoconjugates. Glycogen-like particles were observed in the pseudo-Chediak-Higashi granules with the PA-TCH-SP method, as occasionally observed in granules in drug resistant ALL blasts. In conclusion, the contents of pseudo-Chediak-Higashi granules, which seems to be formed by fusion of small granules, differed from those of normal azurophillic granules.

Adenine nucleotides, serotonin, and aggregation properties of platelets of blue foxes (Alopex lagopus) with the Chediak-Higashi syndrome

Bleeding times, concentrations of serotonin in whole blood, and concentrations of adenine nucleotides as well as aggregation properties of platelets were examined in 18 blue foxes with Chediak-Higashi-like syndrome (CHS) and 16 controls. A claw of each ketamine-sedated fox was cut until bleeding started and the bleeding time was recorded as the time from the first to the last drop. The bleeding time was greatly increased in CHS foxes. Platelet counts of CHS foxes were normal, but aggregation induced by adenosine diphosphate (ADP), serotonin, collagen, and arachidonate was impaired. Adrenaline and serotonin was impaired. Adrenaline and serotonin potentiated the aggregatory effect of ADP on control as well as on CHS platelets. The mean concentration of ADP in CHS platelets was about one-third that in controls, whereas adenosine triphosphate (ATP) was approximately one-half that in controls. Serotonin could not, in most cases, be detected in blood of CHS foxes. These findings suggest that the prolonged bleeding time in the CHS foxes is, at least partly, due to a storage pool deficiency. The drastically reduced, and in some cases absent, aggregation of CHS platelets in response to arachidonate suggests that defective arachidonate metabolism contributes to the impaired hemostasis.

A case report of Chediak-Higashi syndrome complicated with systemic amyloidosis and olivo-cerebellar degeneration

The histopathological observations in the case of a 24 year old woman with Chediak-Higashi syndrome are described. There were characteristic features of cytoplasmic giant granules in various cells and lymphohistiocytic infiltration in various tissues. Amyloid deposits, which have not been reported previously in human Chediak-Higashi syndrome, were systemically noted and were immunohistochemically revealed to be AA type protein. Another rare complication, olivo-cerebellar degeneration, was observed in the central nervous system not associated with lymphohistiocytic infiltration. These complications may develop in long surviving patients with Chediak-Higashi syndrome.

Human non-transformed monocyte-derived macrophage cell lines

We have demonstrated that human blood monocyte-derived macrophages can be passaged from primary cultures and replicate. Passaged cells have typical macrophage characteristics: they are non-specific esterase positive, phagocytic, and respond to 3 days of treatment with interferon-gamma with enhanced production of superoxide on stimulation with PMA. The passaged cells express Fc, CR1, CR3 and FMLP receptors. Both primary and passaged cultures constitutively produce CSF-1 after 3 weeks in culture. Cultures studied between 7 and 16 weeks in culture produce 3712 +/- 478 U of CSF-1 per 10(6) cells. Randomly selected lines were examined to look for cell proliferation by looking at numbers of cells over time and by labelling cells with tritiated thymidine to determine the number of cells synthesizing DNA. In addition, the cells can be frozen at the time of isolation and stored for at least 1 year, and then thawed and shown to retain functional activity. Human monocyte-derived macrophages can be cultured as finite cell lines.

The thiol proteinase inhibitors improve the abnormal rapid down-regulation of protein kinase C and the impaired natural killer cell activity in (Chediak-Higashi syndrome) beige mouse

Protein kinase C (PKC) is essential in intracellular signal transduction for various cell functions including natural killer (NK) cell activity. This enzyme is hydrolysed by calpain, which is Ca2+-dependent thiol proteinase. We showed here that in NK activity-deficient beige (bg/bg) mouse, the model of Chediak-Higashi syndrome, the translocated membrane-bound PKC activity declined rapidly in NK cell-enriched lymphocytes after TPA stimulation. However, the rapid decline was abolished by the pretreatment of cells with leupeptin (a thiol and serine proteinase inhibitor) or E64 (a thiol proteinase inhibitor). Furthermore, these reagents improved the impaired NK cell activity in beige mouse whereas they did not affect NK cell activity in C57BL/6 (+/+) and the heterozygous (+/bg) mice. Meanwhile, TPA stimulation induced only low levels in NK cytotoxic factors (NKCF) release from beige NK cells, but these reagents augmented the lowered NKCF release. These results suggest that the improvement of impaired NK cell activity in beige mouse by the thiol proteinase inhibitors may be due to the elimination of abnormal rapid down-regulation of PKC, resulting in the augmentation of the lowered PKC activity.

An abnormal calcium uptake pump in Chediak-Higashi neutrophil lysosomes

Calcium is mobilized from intracellular stores during phagocyte activation and appears to be involved in stimulus-response coupling in these and other cell types. Because the lysosome is a calcium-sequestering organelle in the neutrophil and abnormal lysosome morphology is associated with defective neutrophil function in Chediak-Higashi syndrome (CHS), we examined ATP-dependent calcium uptake in neutrophil lysosomes from the beige mouse model of CHS. We present findings indicating that CHS lysosomes have an enhanced capacity for ATP-dependent calcium uptake relative to control lysosomes. Kinetic analysis showed differences in Vmax and in the Km for both ATP and calcium, suggesting that both the number of lysosomal calcium uptake pumps and their substrate affinity may be altered in CHS. We conclude that a genetically determined abnormality of a subcellular calcium transport system may contribute to the structural and functional defects of CHS cells.

Alterations of NAD and adenylyl dinucleotide metabolism in Chediak-Higashi syndrome fibroblasts

Chediak-Higashi syndrome (CHS) cells have been previously observed to exhibit several of the same characteristics as those of xeroderma pigmentosum (XP) and xeroderma pigmentosum variants. Cultured CHS fibroblasts have been examined for altered responses in both depletion of NAD and elevation of diadenosine-5',5"'-tetraphosphate (Ap4A) following DNA damage since both responses have been reported as altered in XP cells and since Ap4A has been reported as absent from the platelets of CHS patients. Lowering of NAD following UV irradiation occurred in CHS cells in a manner similar to that of control and XP variant cells, but different from that of XP cells. CHS fibroblasts were not found to be deficient in Ap4A and exhibit basal levels very similar to those of control fibroblasts. No change in Ap4A pools were observed which correlated with cell growth, in contrast to previously published reports. Furthermore, while Ap4A levels are not elevated in XP cells, we observe an elevation of Ap4A pools in CHS cells which mimics the elevations observed in control and XP variant cells. We conclude that: (1) CHS cells more closely resemble control or XP variant cells than XP cells with regard to NAD lowering and Ap4A elevation following UV irradiation; (2) the photosensitivity exhibited by CHS cells is not due to general defects in the synthesis of poly(ADP-ribose) from NAD or in Ap4A metabolism; and (3) alteration of Ap4A pool size in CHS fibroblasts is inappropriate as a biochemical marker for CHS.

Oxygen radical generation by polymorphonuclear leucocytes of beige mice

Oxygen radical generation was measured using peritoneal exudate polymorphonuclear leucocytes (PMN) from a strain of beige mice, an animal model of the Chediak-Higashi syndrome. These PMN have been shown to exhibit delayed microbial killing and impaired phagosome-lysosome fusion. The amount of superoxide anion released by the PMN of the beige mice was similar to that released by the PMN of the control mice. The PMN of beige mice generated slightly less hydrogen peroxide than the control. Hydroxyl radical (.OH) generation and luminol-dependent chemiluminescence were significantly lowered in beige PMN stimulated with opsonized zymosan (OZ) or phorbol myristate acetate (PMA). Cytochalasin B-treated beige PMN showed a decreased ability to degranulate myeloperoxidase in response to OZ or PMA. We demonstrated the significant decrease in .OH generation and chemiluminescence in beige PMN, which might be one of the reasons to explain delayed microbial killing.

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.

Normal serotonin uptake by blood platelets and brain synaptosomes but selective impairment of platelet serotonin storage in mice with Chediack-Higashi syndrome

The Chediack-Higashi syndrome (CHS) is an autosomal recessive disorder reported in man and in several animal species including the "beige mice" (bg/bg). Among several manifestations of this genetic trait, deficiency of secretable substances - including serotonin - normally stored in platelet dense granules is a characteristic feature. The animal model of Chediak-Higashi syndrome used in the present study provides a unique opportunity to compare the kinetics of serotonin (5-hydroxytryptamine, 5-HT) uptake in platelets and brain synaptosomes in conditions of selective reduction of 5HT concentration in the platelets. The kinetics of 5HT uptake, as measured in the present study, was normal in synaptosomes and platelets from the same animals. The lower intraplatelet 5HT levels in bg/bg animals as compared to normal synaptosomes levels in the presence of normal uptake offer an indirect proof that the 5HT defect described in the CHS is due to an impaired 5HT storage mechanism. This is supported by the observation that spontaneous release of 5HT was markedly increased in platelets from CH5 mice but was normal in synaptosomes from the same animals. Thus platelets are a reliable model to study 5HT uptake, but not 5HT storage and release in brain synaptosomes.

Enhanced plasminogen-activator production by leukocytes in the human and murine Chediak-Higashi syndrome

We have studied the coagulation status of eight patients with the Chediak-Higashi syndrome (CHS), both in the chronic and the accelerated phase of the disease. It has been shown that during the accelerated phase there are coagulation abnormalities. These abnormalities include a peripheral thrombocytopenia, minor alterations of liver clotting factors, and mainly a profound hypofibrinogenemia and hypoplasminogenemia, which cause life-threatening bleedings. These disorders are of complex origin, but a fibrinolytic process, possibly primary, appears to play a significant role, since the present evidence for intravascular coagulation is not definitive. The accelerated phase of the CHS is characterized by a visceral infiltration by macrophages and lymphocytes. Therefore, we have investigated the possible role of the macrophages in the fibrinolytic process. We have found an excessive plasminogen activator (PA) production by CHS mononuclear cells in the accelerated phase and to a lesser extent in the chronic phase, except in one patient in whom no anomaly was found. Single-cell studies revealed an increased number of PA-producing cells among the monocyte-macrophage lineage rather than a higher level of production per cell. Polymorphonuclear cells (PMN) from patients with CHS were also shown to contain more PA. Slight but significant abnormalities in PA production were observed in obligatory heterozygotes (five out of nine), indicating the inherited nature of the excessive PA production. Finally, an enhanced PA production was similarly demonstrated using beige mice macrophages. The exacerbated production of PA by macrophages in the accelerated phase of the CHS can account to some extent for the coagulation abnormalities that have been observed.

Reduced collagen biosynthesis in oral mucosa of beige (Chediak-Higashi) mice

Oral mucosa of beige (Chediak-Higashi) mice had decreased levels of collagen synthesis and prolyl hydroxylase activity compared with normal animals. No significant difference was observed in non-collagen protein synthesis between the two groups. These results suggest that decreased collagen biosynthesis in oral tissues may be partially involved in the increased incidence of periodontal disease in the Chediak-Higashi syndrome.

Impaired bone resorption of cultured calvaria from mice with abnormal lysosomal function (the Chediak-Higashi syndrome)

Spontaneous bone resorption is reduced in cultured calvarial bones from mice with the Chediak-Higashi syndrome, as indicated by decreased mobilization of calcium from the bones to the medium. Although bone resorption in calvaria from mice with this disease can be stimulated by PGE2 and 1 alpha (OH)D3, the amounts of mineral released after stimulation is also decreased.

High sensitivity but normal DNA-repair activity after UV irradiation in Epstein--Barr virus-transformed lymphoblastoid cell lines from Chediak--Higashi syndrome

We established lymphoblastoid cell lines from 2 children with Chediak--Higashi syndrome (CHS), 2 xeroderma pigmentosum (XP) patients and control donors after transformation of peripheral lymphocytes by Epstein--Barr virus (EBV). We used these lymphoblastoid cell lines to investigate repair activity after ultraviolet irradiation. Cell survival of both CHS lymphoblastoid cell lines after irradiation by UV and treatment by 4-nitroquinoline 1-oxide (4NQO) fell between those of the XP and control cell lines. Unscheduled DNA synthesis of CHS cells after UV irradiation occurred at rates similar to those of control cells.

Pulmonary surface-active materials in the Chediak-Higashi syndrome

Beige mice express the Chediak-Higashi syndrome. Large inclusions, identified as abnormal lysosomes, are found in many cells. The inclusions in type II alveolar epithelial cells are enlarged lamellar bodies and they are associated with an increase in total lung surface-active material and phospholipid. Comparison of recovery of phospholipid in surface-active materials from beige and black (normal) mice indicates that in the beige mice there is an increase in total phospholipid and disaturated phosphatidylcholines in whole lung and in surface-active materials in residual lung after lavage. Hosphatidycholine and phosphatidylglycerol are increased as percentages of total lung phospholipid. Calculated alveolar surface coverage of surface-active materials isolated from residual beige lungs is greater than three times that of normal lungs. Surface-active materials recovered from beige mice are qualitatively similar in phospholipid composition and in surface activity to materials recovered from normal mice. The quantity of surface-active material phospholipid recovered in the lavage of beige mouse lungs was normal. The basis for the abnormal accumulation of lamellar body lipids is not known.

Protein degradation in normal and beige (Chediak-Higashi) mice,

The beige mouse, C57BL/6 (bg/bg), is an animal model for the Chediak-Higashi syndrome in man, a disease characterized morphologically by giant lysosomes in most cell types. Half-lives for the turnover of [(14)C]bicarbonate-labeled total soluble liver protein were determined in normal and beige mice. No significant differences were observed between the normal and mutant strain for both rapidly and slowly turning-over classes of proteins. Glucagon treatment during the time-course of protein degradation had similar effects on both normal and mutant strains and led to the conclusion that the rate of turnover of endogenous intracellular protein in the beige mouse liver does not differ from normal. The rates of uptake and degradation of an exogenous protein were determined in normal and beige mice by intravenously injecting (125)I-bovine serum albumin and following, in peripheral blood, the loss with time of phosphotungstic acid-insoluble bovine serum albumin and the parallel appearance of phosphotungstic acid-soluble (degraded) material. No significant differences were observed between beige and normal mice in the uptake by liver lysosomes of (125)I-bovine serum albumin (t((1/2)) = 3.9 and 2.8 h, respectively). However, it was found that lysosomes from livers of beige mice released phosphotungstic acid-soluble radioactivity at a rate significantly slower than normal (t((1/2)) = 6.8 and 3.1 h, respectively). This defect in beige mice could be corrected by chronic administration of carbamyl choline (t((1/2)) = 3.5 h), a cholinergic agonist which raises intracellular cyclic GMP levels. However, no significant differences between normal and beige mice were observed either in the ability of soluble extracts of liver and kidney to bind [(3)H]cyclic GMP in vitro or in the basal levels of cyclic AMP in both tissues. The relevance of these observations to the presumed biochemical defect underlying the Chediak-Higashi syndrome is discussed.

Brain serotonin concentration and crude synaptosomal uptake in mice with the Chediak-Higashi syndrome

The Chediak-Higashi syndrome is characterized by a serotonin platelet defect and neuronal dysfunction. Whole blood serotonin concentration, serotonin brain concentration, and synaptosomal uptake of serotonin were determined in mice with the syndrome. While brain serotonin uptake in the affected mice was not significantly different from that in nonaffected mice, whole blood serotonin concentration was markedly reduced. These data suggest that in human neuropathies with platelet serotonin defect, a parallel neuronal serotonin disorder may not be assumed.

Age-related accumulation of ceroid-like pigment in mice with Chediak-Higashi syndrome

The Chediak-Higashi Syndrome (CHS) is a rare inherited disorder occurring in man and several animal homologs including the beige mouse; it is characterized by pigmentary dilution, susceptibility to pyogenic infections, and the presence of enlarged lysosomes in many cell types. Beige mice 6 months of age and older were found to have darkened livers, kidneys, and spleens, accompanied by splenomegaly. A fluorescence microscopic survey of tissues from beige mice revealed marked accumulations of a microscopic survey of tissues from beige mice revealed marked accumulations of a yellow autofluorescent pigment inhepatocytes, renal proximal tubule cells, and splenic macrophages. Additionally, large amounts of hemosiderin were present in the spleen. In beige mice, the pigment was noted in animals as young as 1 to 2 weeks of age and gradually increased in amount as the animals aged. A histochemical investigation of the pigment showed that it was ceroid-like in nature and contained in lysosomes. Ultrastructurally, the pigment was composed of lipid-like droplets embedded in a dense matrix and surrounded by a limiting membrane. The accumulation of ceroid-like material in beige mice may be a reflection of the metabolic disturbance which underlies CHS.

Correction of characteristic abnormalities of microtubule function and granule morphology in Chediak-Higashi syndrome with cholinergic agonists

Chediak-Higashi (CH) syndrome is a genetic disorder of children and certain animal species including the beige mouse. We have previously described a membrane abnormality in CH mouse polymorphonuclear leukocytes (PMH). Whereas normal mouse PMN do not form surface caps with concanavalin A except after treatment with agents such as colchicine that inhibit microtubule assembly, CH mouse PMN show spontaneous cap formation. This capping is inhibited by 3',5 cyclic guanosine monophosphate and by the cholinergic agonists carbamylcholine and carbamyl beta-methylcholine that increase 3',5' cyclic guanosine monophosphate generation. These data suggested that microtubule function may be impaired in CH syndrome perhaps secondary to an abnormality in 3',5' cyclic guanosine monophosphate generation. The cholinergic agonists were also shown to prevent development of the giant granules that are pathognomonic of CH syndrome in embryonic fibroblasts isolated from CH mice and cultured in vitro. In this report it is shown that an extreme degree of spontaneous concanavalin A cap formation is also characteristic of peripheral blood PMN from two patients with CH syndrome. This indicates an abnormality of microtubule function in CH syndrome in man. 3',5' cyclic guanosine monophasphate, carbamylcholine, and carbamyl beta-methylcholine reduce spontaneous capping in CH cells. In addition, it is shown that monocytes isolated from the patients' blood and incubated in tissue culture generate a large complement of abnormal granules. When the same cells mature in vitro in the presence of carbamylcholine or carbamyl beta-methylcholine, the proportion of cells containing morphologically normal granules is significantly increased. These responses can be reproduced in vivo in the beige (CH) mouse. Animals treated for 3 wk and longer with carbamylcholine or carbamyl beta-methylcholline show normal granule morphology and a normal degree of concanavalin A cap formation in peripheral blood PMN leukocytes.

Serotonin deficiency and prolonged bleeding in beige mice

Beige mice have been observed to bleed excessively from small wounds. Platelets obtained from these mice were deficient in adenine nucleotides and serotonin and in vivo uptake of labeled serotonin was impaired. Heterozygotes of beige and C57BL/6 mice have adenine nucleotide and serotonin levels comparable to control and do not manifest a bleeding tendency, consistent with the recessive mode of inheritance of the beige mouse syndrome. Morphologic confirmation of the observed biochemical defects was obtained by the demonstration that serotonin storage organelles were not observed in electron photomicrographs of beige mouse platelets. The demonstration that small doses of serotonin were effective in reversing the bleeding tendency in beige mice suggested a causal role for defective storage and release of endogenous serotonin as the basis for the bleeding tendency, acting either independently or synergistically with impaired release of adenine nucleotides.

Leukocyte dysfunction in the bovine homologue of the Chediak-Higashi syndrome of humans

The increased susceptibility to pyogenic infections noted in cattle with the Chediak-Higashi syndrome trait has been related to an impairment of leukocyte function at the cellular level. Investigations of the relationship of abnormal granule formation to increased susceptibility to infection, conducted with cell suspensions containing high concentrations of polymorphonuclear leukocytes, revealed a bactericidal defect that was associated with abnormal intracellular killing and not due to defective particle ingestion. The in vitro bactericidal defect was associated with a metabolic anomaly in the hexose monophosphate shunt, but not with an alteration in the capacity to reduce nitroblue tetrazolium dye. Ultrastructural histochemical studies of phagocytosis and phagolysosome formation in polymorphonuclear leukocytes suggest that the impairment in bactericidal capacity is correlated also with either a delay or failure of primary granules to degranulate.

Defective function of renal lysosomes in mice with the Chediak-Higashi syndrome

Morphologically abnormal lysosomes demonstrated in individuals with the Chediak-Higashi syndrome (CHS) suggested a defect in the function of these abnormal lysosomes. To gain direct experimental evidence of such a defect, horseradish peroxidase (HRP) was injected intravenously into CHS and control mice, the mice killed at varying intervals and the kidneys studied by ultrastructural cytochemistry. No morophologic difference was observed in the absorption and uptake of HRP by proximal convoluted tubules in the two groups of mice. In CHS mice, however, some of the HRP fused with enlarged lysosomes. By 48 hours after injection, the lysosomes of normal mice had digested all but trace amounts of HRP, whereas large amounts were still present in CHS mice at this time. In CHS mice, moderate amounts were still present at 72 hours and trace amounts 96 hours post injection. This slowed rate of digestion of HRP by lysosomes of the proximal convoluted tubule cells of CHS mice suggests a similar defect in all cells in CHS individuals in which there is a lysosomal degradation of protein or other matter obtained by endocytosis. Such a defect may explain some manifestations of impaired host defense observed in CHS.