Hematopoyesis Clonal de Potencial Indeterminado (HCPI): más allá de un modelo de campo de cancerización / Clonal hematopoiesis of indeterminate potential (CHIP): Beyond a model of field cancerization

Resumen La Hematopoyesis Clonal de Potencial Indeterminado (HCPI), más conocida como CHIP por sus siglas en inglés, se define como la expansión clonal de Células Madre Hematopoyéticas (CMHs) que albergan una o más mutaciones somáticas (en la mayoría de los casos una sola mutación) sin un cáncer hematológico subyacente ni evidencia morfológica definitiva de displasia, con una frecuencia alélica mayor al 2%. Los individuos con HCPI progresan a malignidad a una tasa de cerca del 0.5% a 1% por año, convirtiéndose así en un modelo de campo de cancerización. Sin embargo, sus implicaciones van más allá debido a que se ha encontrado asociación con enfermedades inflamatorias crónicas, como enfermedad cardiovascular ateroesclerótica, diabetes y enfermedades autoinmunes. Además, es considerado un factor predictivo en pacientes con cáncer hematolológico y no hematológico que reciben quimioterapia y radioterapia.

Abstract Clonal hematopoiesis of indeterminate potential (CHIP) is the expansion of hematopoietic stem cells harboring one or more somatic mutations. These patients do not have underlying hematologic neoplasia, myelodysplasia, or dysplasia, but can progress to a malignant state at a rate of 0.5 to 1% per year. CHIP could be used as a model of field cancerization, since it has been associated with chronic inflammatory diseases, arteriosclerosis, diabetes, and autoimmune conditions. CHIP is also considered a predictive factor in hematological and non-hematological cancer patients receiving chemotherapy and radiotherapy.

C/EBPb converts bovine fibroblasts to adipocytes without hormone cocktail induction

BACKGROUND: Adipogenesis and fibrogenesis can be considered as a competitive process in muscle, which may affect the intramuscular fat deposition. The CCAAT/enhancer-binding protein beta (C/EBPb) plays an important role in adipogenesis, which is well-characterized in mice, but little known in bovine so far. RESULTS: In this study, real-time qPCR revealed that the level of C/EBPb was increased during the developmental stages of bovine and adipogenesis process of preadipocytes. Overexpression of C/EBPb promoted bovine fibroblast proliferation through mitotic clonal expansion (MCE), a necessary process for initiating adipogenesis, by significantly downregulating levels of p21 and p27 (p < 0.01). Also, the PPARc expression was inhibited during the MCE stage (p < 0.01). 31.28% of transfected fibroblasts adopted lipid-laden adipocyte morphology after 8 d. Real-time qPCR showed that C/EBPb activated the transcription of early stage adipogenesis markers C/EBPa and PPARc. Expression of ACCa, FASN, FABP4 and LPL was also significantly upregulated, while the expression of LEPR was weakened. CONCLUSIONS: It was concluded C/EBPb can convert bovine fibroblasts into adipocytes without hormone induction by initiating the MCE process and promoting adipogenic genes expression, which may provide new insights into the potential functions of C/EBPb in regulating intramuscular fat deposition in beef cattle.

Flavonoids kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone inhibit mitotic clonal expansion and induce apoptosis during the early phase of adipogenesis in 3T3-L1 cells / 中西医结合学报

OBJECTIVE@#Kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone (DTMC) are two major flavonoids found in Chromolaena odorata Linn. leaf extract. The aim of this study was to elucidate the mechanism by which these two flavonoids exerted their effect on adipogenesis. The inhibitory effect of kaempferide and DTMC on adipocyte differentiation and their mechanisms involving mitotic clonal expansion (MCE) and apoptosis during the early stage of adipogenesis were investigated.@*METHODS@#Confluent 3T3-L1 preadipocytes were induced to differentiate and exposed to the flavonoids during various phases of differentiation. Intracellular lipid accumulation, cell density and expression of the transcription factors peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins α were assessed using AdipoRed, Oil red O and Western blot assays. Effects of both flavonoids on cell proliferation and apoptosis were also determined by carboxyfluorescein diacetate succinimidyl ester and annexin V-fluorescein isothiocyanate/propidium iodide-staining assays, respectively.@*RESULTS@#Kaempferide and DTMC showed significant, concentration-dependent anti-adipogenic activity and effect on cell density in the early phase of adipogenesis. The expression of the transcription factors seemed to be reduced when the treatment was prolonged or in the early phase of adipogenesis. These flavonoids interrupted MCE via inhibition of preadipocyte proliferation and induction of apoptosis. DTMC was nearly three times more potent than kaempferide in inducing apoptosis.@*CONCLUSION@#Kaempferide and DTMC exerted their anti-adipogenic activity through inhibition of MCE, either by suppressing cell proliferation or by inducing apoptosis during the early phase of differentiation.

Advances in pathogenesis, diagnosis and treatment of paroxysmal nocturnal hemoglobinuria / 白血病·淋巴瘤

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder of hematopoietic stem cells due to acquisition of somatic mutations.Somatic mutations in phosphatidylinositol glycan class A (PIGA) account for intravascular hemolysis and other PNH manifestations,but the pathophysiology of clonal expansion of PNH cells cannot be elucidated clearly.PNH is closely related to aplastic anemia and myelodysplastic syndromes.Today,the gold standard for PNH is flow cytometry to detect the absence or severe deficiency of glycosylphosphatidylinositol (GPI)-anchored proteins on white and red blood cells.However,PNH diagnosed by phenotype is a group of heterogeneous disease in pathogenesis.Eculizumab,a first-in-class monoclonal antibody that inhibits terminal complement,is highly effective in stopping intravascular hemolysis and improving quality of life.Further research on the pathogenesis of PNH would be helpful to understand the underlying reasons for PNH phenotype cells in different patients,improve differential diagnosis and more targeted and specific therapy.Research progress in recent years will be reviewed in this article.

Maintenance of Epstein-Barr virus latent genome in epithelial tumor cells during the cellular clonal expansion / 中南大学学报(医学版)

Objective To determine the maintenance and loss of Epstein-Barr virus (EBV) genome during the clonal expansion of the EBV-infected epithelial cells. Methods The epithelial tumor cell line, 293-EBV, in which the EBV genome was observed with green fluorescent protein (GFP) readout. After a dozen of passages, it contained cells with strong or weak GFP expression, and some with complete loss of EBV genome. The cell growth was then continuously observed under a confocal microscope. The cell dividing and GFP expression were also observed during the clonal expansion by being made into very low density. Results The cells moved around due to adherence and mobility, while the GFP expression remained unchanged in the undivided cells. The cells could form compact or loosen clones. The EBV genome easily persisted in those clones when cells were growing compactly. As the cell number increased, the GFP expression became weak or even died away at the sites of low density in the loosen clones. Conclusion EBV-positive epithelial cells are able to sustain the EBV genome during its clonal expansion. The cells maintain EBV genomes by passing them to the daughter cells after replication. When the cells unsuccessfully inherit the EBV genome, the daughter cells may lose them which is related to the low cell density as well as the epithelial environment.

Clonal expansion and genetic diversity of nalidixic acid-resistant Salmonella enterica serotype Paratyphi A in Yuxi city, China / 中华微生物学和免疫学杂志

Objective To understand the elonal expansion and genetic diversity of Salmonella en-terica semtype Paratyphi A (SPA) and to construct a typing method to determine the epidemic clones of the isolates. Methods Antimicrobial susceptibility testing was performed with 3980 SPA isolates by the cen-trolled Kirby-Bauer disc diffusion technique on Muller-Hinton agar plates. A total of 15 SPA with nalidixie acid resistance for mutations in gyrA, gyrB, gyrC and gyrE genes within the quinolone-resistant determina-tion region (QRDR) were examined. Subtyping of 121 isolates of SPA from seven counties in Yuxi were studied using pulsed-field gel eleetrophoresis (PFGE) analysis following digestion of chromosomal DNA with restriction endanucleases Spe Ⅰ and Xba Ⅰ. PFGE patterns were analyzed by duster analysis. Results The nalidixic acid-susceptible isolates predominated in 1999 but was replaced by nalidixic acid -resistant (NAR) isolates after 2000. Amplification by PCR and sequencing of the genes with subsets of 15 NAR strains re-vealed that the resistance mechanisms had resulted from single point mutations in the gyrA gene. Spe Ⅰ and Xba Ⅰ digestion of 121 isolates gave five and four different PFGE patterns with the predominance of the Spe Ⅰ 01 and Spe Ⅰ 02 (or the Xba Ⅰ 01) epidemic patterns, respectively. Spe Ⅰ 01 and Spe Ⅰ 02 consisted of 37.2% and 57.9% of isolates, respectively, or Xba Ⅰ 01 consisted of 95.0% of isolates. Conclusion The incidence of resistance to nalidixic acid of the isolates increased during the study period. PFGE patterns Spe Ⅰ 01 and Spe Ⅰ 02 (or Xba Ⅰ 01), the main clones of the epidemics, are highly prevalent in Yuxi. PFGE with Spe Ⅰ and Xba Ⅰ is a useful technique to differentiate SPA.

Clonal Expansion of Peripheral B Cells in Kawasaki Disease / 소아알레르기및호흡기학회지

PURPOSE: The etiology and pathogenesis of Kawasaki disease(KD) remains unknown and KD is a potentially fatal acute systemic vasculitis of childhood. Recently, expansions of T cells expressing TCR(T cell receptor) Vbeta2 and TCR Vbeta8 chanins have been reported, and this suggests the involvement of a superantigen in the pathogenesis of KD. With the stimulation with superantigen, polyclonal B cell activation can be observed. However, there was no report on the polyclonal or oligoclonal B cell activation in the peripheral blood of the KD. We investigated clonal expansion to search for the evidence of clonality of the peripheral B cell in KD and for the evidence of the superantigen involvement in KD. METHODS: Peripheral mononuclear cells of acute and subacute phase of KD were stained for immunophenotype. Total RNA was extracted from peripheral mononuclear cells of the patients and cDNA was prepared. Primary PCR and second round PCR were done for analysing the CDR3 region. Cloning and sequencing were done, and VH3 family gene sequences were compared with immunoglobulin germline sequence. RESULTS: The percentage of B cells in KD increased significantly(P<0.05) in both acute and subacute phases compared to those of normal controls. Random utilization of diverse VH family genes was observed in the acute phase, and no specific expansion of VH family was detected. An increase in B cells expressing the VH3 family was seen during acute phase. Analysis of CDR3 size profile showed that various prominent bands appeared in acute phase, and some disappearing in the convalescent, while other new bands were developed in convalescent phase. IgM VH transcripts showed that DH6 and JH4 were used most commonly which showed the evidence of oligoclonality. However, DNA sequences of CDR3s of VH3 showed no dominant clones. CONCLUSION: These data suggest KD may be caused by conventional antigens rather than superantigen. DNA sequences of all 6 VH families should be searched further.

Oligoclonal Expansion of the VH Family in Kawasaki Disease

PURPOSE: To search for evidence of B cell activation and superantigen involvement in Kawasaki disease. METHODS: Peripheral lymphocytes were first isolated from Kawasaki disease patients in the acute and subacute phases. The T cell and B cell distributions were analyzed, cDNA was generated from the total RNA extracts, and PCR amplification of the cDNA for each immunoglobulin heavy chain family was performed to determine the presence of VH family-specific oligoclonal expansion. CDR3 size analysis was then conducted by two-stage PCR. RESULTS: The percentage of B cells increased significantly(P<0.05) in both the acute and subacute phases. Random utilization of diverse VH family genes was observed in the acute phase, and no family-specific expansion was detected. In 13 out of 15 Kawasaki disease patients, an increase in B cells expressing the VH3 family was seen during the acute phase, making it the most frequently utilized family. Analysis of B cell clonal expansion showed the VH6 family clone of 9 amino acids to be the most common clone, observed in 5 out of 15 Kawasaki disease patients. Analysis of the CDR3 size profile in two patients showed that in the acute phase various prominent bands appeared, some disappearing in the subacute phase, while other newly developed bands appeared. CONCLUSION: VH family-specific B cell expansion was not detected, and clonal expansion of B cells was observed, suggesting that Kawasaki disease may be caused by a conventional antigen, and the antigenic stimulation seen during the acute phase seems to be continuous, resuming after clinical resolution.