BACKGROUND AND OBJECTIVES: Recent studies have examined the structure-function relationship of high-density lipoprotein (HDL). This study aimed to identify and rank HDL-associated proteins involved in several biological function of HDL.METHODS: HDLs isolated from 48 participants were analyzed. Cholesterol efflux capacity, effect of HDL on nitric oxide production, and vascular cell adhesion molecule-1 expression were assessed. The relative abundance of identified proteins in the highest vs. lowest quartile was expressed using the normalized spectral abundance factor ratio.RESULTS: After adjustment by multiple testing, six proteins, thyroxine-binding globulin, alpha-1B-glycoprotein, plasma serine protease inhibitor, vitronectin, angiotensinogen, and serum amyloid A-4, were more abundant (relative abundance ratio ≥2) in HDLs with the highest cholesterol efflux capacity. In contrast, three proteins, complement C4-A, alpha-2-macroglobulin, and immunoglobulin mu chain C region, were less abundant (relative abundance ratio <0.5). In terms of nitric oxide production and vascular cell adhesion molecule-1 expression, no proteins showed abundance ratios ≥2 or <0.5 after adjustment. Proteins correlated with the functional parameters of HDL belonged to diverse biological categories.CONCLUSIONS: In summary, this study ranked proteins showing higher or lower abundance in HDLs with high functional capacities and newly identified multiple proteins linked to cholesterol efflux capacity.
Amyloid ; Angiotensinogen ; Atherosclerosis ; Cardiovascular Diseases ; Cholesterol ; Complement System Proteins ; Immunoglobulin mu-Chains ; Lipoproteins ; Nitric Oxide ; Plasma ; Proteomics ; Serine Proteases ; Thyroxine-Binding Globulin ; Vascular Cell Adhesion Molecule-1 ; Vitronectin

OBJECTIVEMutation in the heavy chain micro (microHC) gene causes a rare type of autosomal recessive agammaglobulinemia. Here we report the molecular and clinical characterization of a compound heterozygous mutation in the microHC gene in a patient with autosomal recessive agammaglobulinemia firstly from China.

METHODA one-year and ten-month-old male patient and his parents were enrolled in this study. No mutation was found in BTK gene. The microHC gene of the patient and his parents were amplified by polymerase chain reaction (PCR) from genomic DNA. Reverse transcription polymerase chain reaction (RT-PCR) was used to amplify the microHC transcripts. Sequencing was performed directly on the PCR products bidirectionally.

RESULTSSince 8 months of age, the patient had had recurrent fever and persistent cough. He suffered an acute right hemiplegia at 11 months of age and swelling and pain of left hip joint and right knee joint at one year and eight months of age. Cerebrospinal fluid routine examination showed that total cell count was 18 x 10(6)/L [normal range (0 - 15) x 10(6)/L], leukocyte count 7 x 10(6)/L [(0 - 15) x 10(6)/L] and biochemical examination showed protein 0.14 g/L (0.15 - 0.45 g/L), glucose 4.68 mmol/L (2.44 - 4.44 mmol/L) and chloride 116.3 mmol/L (120 - 132 mmol/L). Mycobacterium bovis was identified negative by cerebrospinal fluid smear examination. No obvious abnormity was detected on skull CT examination. Hydrothorax examination showed that total cell count was 848 x 10(6)/L, leukocyte count 785 x 10(6)/L and protein 30.8 g/L (< 30 g/L). Poliovirus isolation from stool sample of the patient was negative. The serum immunoglobulin (Ig) profile was IgG 181 mg/L (normal range, 5.09 - 10.09 g/L); IgM 28.8 mg/dl (400 - 1260 mg/dl) and IgA 22 mg/dl (310 - 670 mg/dl), IgE 4.6 U/ml (normal range < 150 U/ml). There were no B-cells but normal percentage of T-cells (67%) and NK cells (32%) were present in the peripheral blood. The patient had a compound heterozygous mutation in the microHC gene:on one allele, there was an alternative splice site mutation in exon 4 (1956 G > A), for which the patient's father was a carrier. Whereas on the other allele, an insert mutation between 170 and 175 in exon 1 with a premature stop codon (170 - 175 insert C, L11fs60X) was identified, for which the patient's mother was a carrier. The insert mutation in exon 1 of microHC gene was firstly reported. To detect the effect of the splice site mutation in exon 4, microHC cDNA of the patient was amplified by semi-nested PCR. The PCR products were purified and sequenced directly. A 136 bp of intron 4 was found in the transcripts and only the secreted isoform with a missense substitution is present in the patient, while synthesis of the membrane isoform is completely abolished.

CONCLUSIONThis is the first case with autosomal recessive agammaglobulinemia with compound heterozygous mutation in the microHC gene reported from China. A novel mutation in exon 1 was found.

Agammaglobulinemia ; congenital ; genetics ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; DNA ; genetics ; DNA, Complementary ; genetics ; Exons ; Heterozygote ; Humans ; Immunoglobulin mu-Chains ; genetics ; Infant ; Male ; Molecular Sequence Data ; Mutation ; Polymerase Chain Reaction