Activation of peroxisome proliferator-activated receptor gamma suppresses mast cell maturation involved in allergic diseases.

BACKGROUND: Mast cells play a central role in allergic and inflammatory diseases. Several reports indicated role of peroxisome proliferator-activated receptor gamma (PPARgamma) on mast cell function. However, there is no report about the role of PPARgamma on differentiation of mast cells from the progenitors. In this study, we investigated the role of PPARgamma in regulating bone marrow-derived mast cell maturation and the therapeutic implications for mast cell-related diseases such as atopic or contact dermatitis. METHODS: We used in vitro cell culture system for mast cell differentiation from bone marrow-progenitors using specific ligands and lentiviral-mediated short hairpin RNA of PPARgamma, and in vivo murine dermatitis models. RESULTS: Activation of PPARgamma inhibited the maturation of bone marrow progenitors into connective tissue-type mast cells (CTMCs) through up-regulation of GATA-4 and GATA-6 resulting in a decrease in expression of histidine decarboxylase and mast cell histamine content. In comparison, the differentiation of bone marrow progenitors into CTMCs was significantly accelerated by the knockdown of PPARgamma expression by lentiviral-mediated short hairpin RNA. Peroxisome proliferator-activated receptor gamma ligand administration to mice inhibited the maturation of mast cells resulting in attenuation of atopic and contact dermatitis via diminishment of the number of mature mast cells. CONCLUSION: Our results indicate that PPARgamma is one of master regulators on mast cell maturation and potentially useful for the therapy in various disorders involving mast cell activation.

1173C>T polymorphism in VKORC1 modulates the required warfarin dose.

The response to warfarin is highly variable among individuals and such variability is likely to have some genetic basis. We evaluted the effect of VKORC1 polymorphisms on warfarin response among Japanese, taking advantage of its unique population structure in which CYP2C9 *2 and *3 alleles are relatively rare. Thirty-one patients (12-34 years old; median, 22) on warfarin were recruited from a pediatric cardiology clinic. Genotyping of the C>T polymorphism at position 1173 in intron 1 of VKORC1 revealed that 26 patients (84%) were T/T homozygotes at nucleotide 1173, whereas 5 (16%) were C/T heterozygotes. Complete linkage disequilibrium was observed between the 1173C > T polymorphism and another polymorphism, the 3730G > A, in the 3' untranslated region. The C/T heterozyogtes at the 1173C > T polymorphism tended to require more warfarin than the T/T homozygotes, when adjusted for international normalized ratio (p = 0.003). Both the 1173C > T polymorphism and the 3730G > A polymorphism are likely to be inert from a functional standpoint. Rather, based on the complete linkage disequilibrium between 1173C > T and 3730G > A polymorphisms, we suspect that the actual change that defines the relative resistance to warfarin may be present in the proximity of these two polymorphisms.

The contribution of mast cells to the late-phase of allergic asthma in rats.

INTRODUCTION: Mast cells are thought to be the main cause of an immediate asthmatic response, but their contribution to the late-phase of asthma is unknown. OBJECTIVE: To prove the contribution of preactivated mast cells to the late phase of allergic asthma by advanced activation. METHODS: Mast cell function in the late-phase of asthma was studied. Rats (wild, +/+ and mast cell deficient, Ws/Ws) were challenged with OVA to investigate the relationship between the contraction of airways and the population of inflammatory cells in the trachea. RESULT: During the entire asthmatic period, the contraction of the airway after OVA challenge in +/+ rats was enhanced significantly compared to Ws/Ws rats, especially in the late phase. The bronchoalveolar lavage fluid histamine in +/+, but not Ws/Ws, rats increased 5.3-fold in 30 min and 3.4-fold in 8 h after challenge, significantly. The number of mucosal mast cells in the tracheal epithelial layer in +/+ rats increased significantly 2.2-fold over controls at 8 h after challenge, as demonstrated by in situ hybridization. CONCLUSIONS: Mast cells may contribute to the late phase of asthmatic response by continuous mast cell activation and the mucosal mast cell number increased in the late phase of asthmatic response.

A novel reaction for annulation onto alpha,beta-unsaturated ketones: W(CO)(5).L promoted exo- and endo-selective cyclizations of omega-acetylenic silyl enol ethers prepared by 1,4-addition of propargyl malonate to enones.

A highly useful method for five- and six-membered ring annulation onto alpha,beta-unsaturated ketones is described. 1,4-Addition of propargylmalonate to alpha,beta-unsaturated ketones in the presence of silyl triflate gives 7-siloxy-6-en-1-yne derivatives in good yield. W(CO)(5).L-catalyzed cyclization of these substrates can be induced to give preferentially either exo- or endo-cyclized products in good yield simply by changing the reaction solvent. [reaction: see text]

Effect of a large deletion of the basic domain of mi transcription factor on differentiation of mast cells.

The mi transcription factor (MITF) is a basic-helix-loop-helix-leucine zipper transcription factor that is important for the development of mast cells. Cultured mast cells (CMCs) of mi/mi genotype express abnormal MITF (mi-MITF), but CMCs of tg/tg genotype do not express any MITFs. It was previously reported that mi/mi CMCs showed more severe abnormalities than tg/tg CMCs, indicating that mi-MITF had inhibitory function. Whereas mi-MITF contains a single amino acid deletion in the basic domain, MITF encoded by mi(ew) allele (ew-MITF) deletes 16 of 21 amino acids of the basic domain. Here the effect of a large deletion of the basic domain was examined. In mi(ew)/mi(ew) CMCs, the expression pattern of genes whose transcription was affected by MITF was comparable to that of tg/tg CMCs rather than to that of mi/mi CMCs. This suggested that ew-MITF lacked any functions. The part of the basic domain deleted in ew-MITF appeared necessary for either transactivation or inhibition of transactivation.

Do mucosal mast cells contribute to the immediate asthma response?

In rat trachea, two types of mast cells have been identified, connective tissue mast cells (CTMCs) and mucosal mast cells (MMCs). We previously reported that CTMCs play an important role in tracheal contraction in vitro via 5-hydroxytryptamine (5-HT) release in a rat model. In this study, we investigated whether MMCs also play a role in tracheal contraction by employing mast cell-deficient (Ws/Ws) rats and their congenic (+/+) rats. Rats were actively sensitized with ovalbumin and challenged with it 2 weeks later. To exclude the influence of CTMCs, rats were pretreated for 7 days with compound 48/80 injected i.p. in increasing doses. Histological study confirmed that degranulation occurred in CTMCs, but MMCs still remained. Histamine levels in trachea decreased to 9.31% of control levels. Ovalbumin-specific IgE production showed a time-dependent increase in both Ws/Ws and +/+ rats after sensitization with no significantly different values between the two groups. Ovalbumin challenge caused contraction of the trachea in sensitized control (+/+) rats, but not in sensitized Ws/Ws and compound 48/80-pretreated +/+ rats. Ketanserin inhibited the contraction, but leukotriene antagonist ONO-1078 did not, indicating that the contraction was due to 5-HT, whereas leukotriene, a mediator specific derived from MMCs, has no significant effect. The results suggest that MMCs has minimal, if any, contribution to tracheal contraction and might have another function. Furthermore, Ws/Ws and the congenic rats provide a good model for studying the role of mast cells in the immunologic response in airways.

Isolation of the third component of complement and its derivative with anaphylatoxin-like activity from the plasma of the newt Cynops pyrrhogaster.

The third component of complement (C3) of a newt, Cynops pyrrhogaster, was purified using a fast protein liquid chromatography technique. The purified newt C3 consists of two polypeptide chains (the molecular masses of the alpha and beta-chains of C3 were 120,000 and 70,000, respectively) linked by disulfide bonds. The alpha-chain retained an internal thiolester bond that was cleaved with methylamine, and the N-terminal amino acid sequence of the alpha-chain was XVQLIDAKAGKAAKF. Digestion of newt C3 with trypsin yielded fragments that induced significant histamine release from newt peritoneal cells. These results indicate that newt C3 retains structural and functional properties shared with mammalian C3.

Mutation analysis of left-right axis determining genes in NOD and ICR, strains susceptible to maternal diabetes.

BACKGROUND: Genetic background of the fetus contributes to the pathogenesis of congenital malformation after teratogen exposure. Such contribution is illustrated in left-right axis malformations observed in the F1 offspring of nonobese diabetic (NOD) mouse dams and sires from different strains. When sires of the NOD, ICR, or C57BL/6J were mated with NOD dams, incidence varied depending on the fetal genotype, with 65% in NOD x NOD, 24% in NOD x ICR, and 7% in NOD x C57BL/6J. METHODS: As a first step in elucidating the molecular basis of the interstrain differences in susceptibility to situs defects, we compared genomic sequences of six genes HNF3beta, Acvr2b, Nodal, ZIC3, Lefty1, and Smad2, which are involved in the normal development of left-right axis among NOD, ICR, and C57BL/6J strains. RESULTS: The outbred strain ICR had 1) a 0.2-kb insertion in the putative promoter region of the isoform E of HNF3beta together with a G to A change that could create a potential splice acceptor in the exon 3 of HNF3beta (gene frequency P = 0.36), 2) five single base substitutions within the 5' controlling element and a proline to serine substitution (P2S) of Lefty1 (P = 0.77), and 3) a tyrosine to histidine substitution within the prodomain of Nodal (P = 0.48). The inbred strain NOD had the same G to A change as ICR and a three-base deletion in the putative promoter of isoform E of HNF3beta. CONCLUSIONS: We suggest that sequence variations in HNF3beta, Lefty1, and Nodal might account, in part, for the interstrain differences in susceptibility to situs abnormalities among the offspring of diabetic dams.

Screening of several Indonesian medicinal plants for their inhibitory effect on histamine release from RBL-2H3 cells.

Twelve alcoholic extracts and 12 hexane extracts of plant materials selected on the basis of medicinal folklore for asthma treatment in Indonesia were studied for their activity in inhibiting histamine release from RBL-2H3 cells (rat basophilic leukemia cell line), a tumor analog of mast cells. The results of screening indicated that five alcoholic extracts (Plantago major leaves, Eucalyptus globulus leaves and fruit, Cinnamomum massoiae cortex, Vitex trifolia leaves) and two hexane extracts (Eucalyptus globulus leaves, Vitex trifolia leaves) inhibited IgE-dependent histamine release from RBL-2H3 cells. The inhibitory effects were found to be more than 80% for extract concentrations of 0.5 mg/ml. The results indicate that the extracts contain active compounds that inhibit mast-cell degranulation, and provide insight into the development of new drugs for treating asthma and/or allergic disease.

Importance of leucine zipper domain of mi transcription factor (MITF) for differentiation of mast cells demonstrated using mi(ce)/mi(ce) mutant mice of which MITF lacks the zipper domain.

The mi transcription factor (MITF) is a basic helix-loop-helix leucine zipper (bHLH-Zip) transcription factor that is important for the development of mast cells. Mast cells of mi/mi genotype express normal amount of abnormal MITF (mi-MITF), whereas mast cells of tg/tg genotype do not express any MITFs. Mast cells of mi/mi mice show more severe abnormalities than those of tg/tg mice, indicating that the mi-MITF possesses the inhibitory function. The MITF encoded by the mi(ce) mutant allele (ce-MITF) lacks the Zip domain. We examined the importance of the Zip domain using mi(ce)/mi(ce) mice. The amounts of c-kit, granzyme B (Gr B), and tryptophan hydroxylase (TPH) messenger RNAs decreased in mast cells of mi(ce)/mi(ce) mice to levels comparable to those of tg/tg mice, and the amounts were intermediate between those of +/+ mice and those of mi/mi mice. Gr B mediates the cytotoxic activity of mast cells, and TPH is a rate-limiting enzyme for the synthesis of serotonin. The cytotoxic activity and serotonin content of mi(ce)/mi(ce) mast cells were comparable to those of tg/tg mast cells and were significantly higher than those of mi/mi mast cells. The phenotype of mi(ce)/mi(ce) mast cells was similar to that of tg/tg mast cells rather than to that of mi/mi mast cells, suggesting that the ce-MITF had no functions. The Zip domain of MITF appeared to be important for the development of mast cells. (Blood. 2001;97:2038-2044)

The lack of compound 48/80-induced contraction in isolated trachea of mast cell-deficient Ws/Ws rats in vitro: the role of connective tissue mast cells.

In the rat trachea, two types of mast cells have been identified, connective tissue mast cells and mucosal mast cells. Their different characteristics may account for their different biological functions. The role of connective tissue mast cells in tracheal contraction as one feature of the immediate reaction of asthma was studied in vitro in isolated trachea, using tissue derived from mast cell-deficient (Ws/Ws) rats, heterozygous (Ws/+) rats and control (+/+) rats, and compound 48/80 as a potent inducer of mast cell degranulation. The contractile response of tracheas from the three types of rats was also studied upon exposure to the following spasmogens: histamine, 5-hydroxytryptamine (5-HT), and carbachol. Histamine content in tissues reflected the differing mast cell numbers in strips from the three rat types. It was found that carbachol and 5-HT elicited tracheal contraction in a similar manner in strips from the three types of rats. Histamine had no contractile effect. Compound 48/80, at a dose of 25 microg/ml, elicited contraction in tracheas from both control (+/+) and heterozygous (Ws/+), but not in trachea from Ws/Ws rats. Compound 48/80-induced contractions in tracheas from +/+ rats were inhibited by 0.1 microM ketanserin and 0.1 microM nedocromil, but not by 0.1 microM mepyramine. Enzyme histochemistry confirmed that the degranulation occurred in connective tissue mast cells, but not in mucosal mast cells. We concluded that connective tissue mast cells play an important role in rat tracheal contraction via 5-HT release induced by compound 48/80. In addition, the specific mast cell-deficient (Ws/Ws) rats provide a good tool for studying the roles of mast cells in airway system.

Characterization of histamine H3 receptors in mouse brain using the H3 antagonist [125I]iodophenpropit.

We have characterized the binding of the histamine H3 receptor antagonist [125I]iodophenpropit to mouse brain. [125I]Iodophenpropit saturably bound to mouse brain membranes with a pKd-value of 9.31+/-0.04 nM and a receptor binding density of 290+/-8 fmol per mg protein. Saturation binding analysis revealed binding of [125I]iodophenpropit to a single class of sites, showing linear Scatchard plots and Hill coefficients not different from unity (nH=0.98+/-0.02). At a concentration of 0.25 nM [125I]iodophenpropit, specific binding represented about 75% of the total binding. Competition binding curves for H3 receptor antagonists were fitted best to a one-site model, showing pKi-values in general accordance with the pA2-values obtained in mouse cerebral cortex. Displacement of [125I]iodophenpropit by the H3 receptor agonists (R)-alpha-methylhistamine, immepip, imetit and histamine were fitted best to a two-site model. Competition binding curves of (R)-alpha-methylhistamine showed a rightward shift upon incubation with GTPgammaS (10 microM), indicating the involvement of G-proteins in H3 agonist binding. In contrast, competition binding curves of the antagonists iodophenpropit, thioperamide and burimamide were not affected by GTPgammaS (10 microM). Autoradiographic experiments showed that [125I]iodophenpropit binding sites were heterogeneously distributed, similarly to the distribution of histamine H3 receptors reported in rat brain. Highest densities were observed in the cerebral cortex, the striatum, the nucleus accumbens, the globus pallidus and the substantia nigra. In conclusion, we have demonstrated that in mouse brain, [125I]iodophenpropit selectively binds to histamine H3 receptors. We also observed that the mouse brain H3 receptors labelled by [125I]iodophenpropit displayed binding characteristics and a distribution similar to rat brain.

Imprinting of human GRB10 and its mutations in two patients with Russell-Silver syndrome.

Documentation of maternal uniparental disomy of chromosome 7 in 10% of patients with Russell-Silver syndrome (RSS), characterized by prenatal and postnatal growth retardation and dysmorphic features, has suggested the presence of an imprinted gene on chromosome 7 whose mutation is responsible for the RSS phenotype. Human GRB10 on chromosome 7, a homologue of the mouse imprinted gene Grb10, is a candidate, because GRB10 has a suppressive effect on growth, through its interaction with either the IGF-I receptor or the GH receptor, and two patients with RSS were shown to have a maternally derived duplication of 7p11-p13, encompassing GRB10. In the present study, we first demonstrated that the GRB10 gene is also monoallelically expressed in human fetal brain tissues and is transcribed from the maternally derived allele in somatic-cell hybrids. Hence, human GRB10 is imprinted. A mutation analysis of GRB10 in 58 unrelated patients with RSS identified, within the N-terminal domain of the protein, a P95S substitution in two patients with RSS. In these two cases, the mutant allele was inherited from the mother. The fact that monoallelic GRB10 expression was observed from the maternal allele in this study suggests but does not prove that these maternally transmitted mutant alleles contribute to the RSS phenotype.

Effect of rabeprazole on histamine synthesis in enterochromaffin-like cells of mast cell-deficient (Ws/Ws) rats.

The effect of rabeprazole, the latest proton pump inhibitor, on the serum gastrin concentration, histidine decarboxylase activity and histamine content of the oxyntic mucosa in Wistar rats, mast cell-deficient (Ws/Ws) rats, and their normal type, +/+, rats was investigated. In Wistar rats, 2 weeks of treatment with rabeprazole (30 mg/kg/day, s.c.) induced a 1.8-fold increase in serum gastrin concentration and a 3.9-fold increase in histidine decarboxylase activity of the oxyntic mucosa over the control levels, whereas neither 2- nor 4-week treatment affected the histamine content of the oxyntic mucosa. In Ws/Ws and +/+ rats, the serum gastrin concentration, histidine decarboxylase activity and even histamine content of the oxyntic mucosa were increased significantly as compared with control levels after the 4-week treatment with rabeprazole. Immunohistochemistry using a histamine antibody confirmed the increase in the histamine content of the oxyntic mucosa after the 4-week treatment with rabeprazole. The finding that there were no differences in serum gastrin concentration and histidine decarboxylase activity between Ws/Ws and +/+ rats, both with and without the 4-week treatment, indicates that mast cells do not respond to endogenous hypergastrinemia elicited by acid-inhibitory treatment. Moreover, the present study clarified for the first time that enterochromaffin-like (ECL) cells in Ws/Ws rats synthesize and store histamine in response to gastrin.

Histamine release induced by immobilization, gentle handling and decapitation from mast cells and its inhibition by nedocromil in rats.

The effect of immobilization, gentle handling and decapitation on the level of plasma histamine in Wistar rats was investigated. Mast cell deficient (Ws/Ws) rats were used to characterize the source of elevated histamine in plasma by stress, and the effect of nedocromil, a mast cell stabilizer, on histamine release was assessed in these models in vivo. The plasma histamine concentration of freely moving rats was 93.0+/-2.3 pmol/ml. Gentle handling produced a transient increase in plasma histamine level by 1.9-fold, whereas immobilization resulted in a longer-lasting elevation by 2.6-fold compared to that in the freely moving rats. Decapitation increased the plasma histamine level by 10- to 16-fold compared with that in the freely moving rats. No increase in plasma histamine was found in Ws/Ws rats exposed to stress. Nedocromil inhibited the increase in plasma histamine level induced by stress in a dose-dependent manner. These findings suggest that stress induces histamine release from mast cells in Wistar rats and the extent of this histamine release increases with the severity of stress. Nedocromil proved to be a good pharmacological tool to inhibit stress-induced release of mediators from mast cells.

Activation of sensory nerves participates in stress-induced histamine release from mast cells in rats.

To elucidate the mechanism by which stress induces rapid histamine release from mast cells, Wistar rats, pretreated as neonates with capsaicin, were subjected to immobilization stress for 2 h, and histamine release was measured in paws of anesthetized rats by using in vivo microdialysis after activation of sensory nerves by electrical or chemical stimulation. Immobilization stress studies indicated that in control rats stress induced a 2.7-fold increase in the level of plasma histamine compared to that in freely moving rats. Whereas pretreatment with capsaicin significantly decreased stress-induced elevation of plasma histamine. Microdialysis studies showed that electrical stimulation of the sciatic nerve resulted in a 4-fold increase of histamine release in rat paws. However, this increase was significantly inhibited in rats pretreated with capsaicin. Furthermore, injection of capsaicin into rat paw significantly increased histamine release in a dose-dependent manner. These results suggest that activation of sensory nerves participates in stress-induced histamine release from mast cells.

Different effect of various mutant MITF encoded by mi, Mior, or Miwh allele on phenotype of murine mast cells.

The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). Mutant alleles of mi, Mior, and Miwh are deletion or point mutation of the basic domain by which MITF binds DNA. The basic domain also has nuclear localization potential. In the present study, we compared the mast cell abnormalities of Mior/Mior and Miwh/Miwh mice with those of mi/mi mice, of which many have been described by us. The number of mast cells in the skin of Mior/Mior suckling mice was remarkably decreased from that observed in mi/mi suckling mice, but the number was normal in the skin of Miwh/Miwh suckling mice. The decrease in skin mast cells was more severe in the mi/mi embryos than in mi/mi suckling mice, but the magnitude of the decrease was comparable between Mior/Mior embryos and Mior/Mior suckling mice. The poor mRNA expression of granzyme B and tryptophan hydroxylase genes was observed in all cultured mast cells (CMCs) derived from the spleens of Miwh/Miwh, Mior/Mior, and mi/mi mice. However, the poor expression of mouse mast cell protease-4 (MMCP-4), MMCP-5, and MMCP-6 was observed only in Mior/Mior and mi/mi CMCs. MITF encoded by Miwh mutant allele (Miwh-MITF) showed deficient but demonstratable DNA binding, but mi-MITF and Mior-MITF did not show any DNA binding ability. Although Miwh-MITF and Mior-MITF showed normal nuclear localization potential, the potential was significantly impaired in mi-MITF. The rank order of mast cell abnormality (mi/mi > Mior/Mior > Miwh/Miwh) appears to be related to the functional abnormality of MITF encoded by each mutant gene.

Down-regulation of CXCR4 by human herpesvirus 6 (HHV-6) and HHV-7.

Recent studies have demonstrated that human herpesvirus 6 (HHV-6) and HHV-7 interact with HIV-1 and alter the expression of various surface molecules and functions of T lymphocytes. The present study was undertaken to clarify whether coreceptors for HIV-1, CXCR4 and CCR5, are necessary for HHV-6 and HHV-7 infection. Although CXCR4 and CCR5 appeared not to be the coreceptors for these viruses, marked down-regulation of CXCR4, but not CCR5, was detected in HHV-6 variant A (HHV-6A)-, HHV-6 variant B (HHV-6B)-, and HHV-7-infected cells. Down-regulation of CXCR4 resulted in impairment of chemotaxis and a decreased level of elevation of the intracellular Ca2+ concentration in response to stromal cell-derived factor-1. Northern blot analysis of mRNAs extracted from HHV-6A-, HHV-6B-, and HHV-7-infected CD4+ T lymphocytes demonstrated a markedly decreased level of CXCR4 gene transcription, but the posttranscriptional stability of CXCR4 mRNA was not significantly altered. These data demonstrate that unlike HIV-1, HHV-6 and HHV-7 infections do not require expression of CXCR4 or CCR5, whereas marked down-regulation of CXCR4 is induced by these viruses, suggesting that HHV-6 and HHV-7 infections may render CD4+ T lymphocytes resistant to T lymphocyte-tropic HIV-1 infection.

Inhibitory effect of the transcription factor encoded by the mi mutant allele in cultured mast cells of mice.

The mi locus of mice encodes a transcription factor of the basic-helix-loop-helix-leucine zipper protein family (MITF). The MITF encoded by the mutant mi allele (mi-MITF) deletes 1 of 4 consecutive arginines in the basic domain. The mice of mi/mi genotype express mi-MITF, whereas the mice of tg/tg genotype have a transgene at the 5' flanking region of the mi gene and do not express any MITF. To investigate the function of mi-MITF in cultured mast cells (CMCs), we took two approaches. First, mRNA obtained from mi/mi CMCs or tg/tg CMCs was subtracted from complementary (c) DNA library of normal (+/+) CMCs, and the (+/+-mi/mi) and (+/+-tg/tg) subtraction libraries were obtained. When the number of clones that hybridized more efficiently with +/+ CMC cDNA probe than with mi/mi or tg/tg CMC cDNA probe was compared using Southern analysis, the number was larger in the (+/+-mi/mi) library than in the (+/+-tg/tg) library. Second, we compared mRNA expression of six genes between mi/mi and tg/tg CMCs by Northern analysis. The transcription of three genes encoding mouse mast cell proteases was impaired in both mi/mi and tg/tg CMCs. On the other hand, the transcription of three genes encoding c-kit receptor, tryptophan hydroxylase, and granzyme B was markedly reduced in mi/mi CMCs, but the reduction was significantly smaller in tg/tg CMCs. These results indicated the inhibitory effect of mi-MITF on the transactivation of particular genes in CMCs.