Polymorphisms in genes of the BAFF/APRIL system may constitute risk factors of B-CLL--a preliminary study on a Polish population.

The association of single-nucleotide polymorphisms (SNPs) of B-cell activating factor (BAFF)/a proliferation-inducing ligand (APRIL) system with B-cell chronic lymphocytic leukemia (B-CLL) have been suggested, therefore, we investigated 20 SNPs of BAFF, APRIL, BAFF-R, transmembrane activator and calcium modulator and cyclophilin-ligand interactor (TACI), B-cell maturation antigen (BCMA) genes and the risk and outcome of B-CLL in 187 patients and 296 healthy subjects as well as ligand-receptor gene × gene interactions. Although the obtained P-values for all 20 SNPs did not reach statistical significance for this study (α = 0.003), the high value of the global chi-squared statistic (χ(2) df = 38 = 52.65; P = 0.0586), and obtained values of odds ratio indicate that rs9514828 (BAFF), rs3803800 (APRIL) and rs4985726 (TACI) may be associated with the risk of B-CLL. We observed that the B-CLL patients with the genotype rs9514828CT/rs11570136AA were diagnosed with the disease 12 years later than the whole group of patients in this study.

ALCAM and CD6--multiple sclerosis risk factors.

ALCAM and CD6 may play an important role in the pathogenesis of multiple sclerosis (MS), since they are involved in the transmigration of leukocytes across the blood-brain barrier. In this study, we confirmed our previous findings about the association of the ALCAM gene with risk, development and progression of MS. Additionally, we showed that in the case of the CD6 gene (encoding receptor of ALCAM) not only polymorphisms but also mRNA expression level are associated with MS. Our analysis revealed that the risk of the disease for AA individuals in rs12360861 was almost 3.0-fold lower in comparison to GG individuals (OR=0.34; CI95%=0.12; 0.81). Moreover, we observed lower expression of CD6 mRNA in patients than in healthy individuals (T(2)2,74=6.678; p=0.002).

Investigation of gene-gene interactions between CD40 and CD40L in Polish multiple sclerosis patients.

CD40-CD40L interaction is necessary for the activation of both humoral and cellular immune response and has been suggested to play a role in the pathogenesis of multiple sclerosis (MS). Therefore, we analyzed the combined influence of the CD40 and CD40L variants on MS susceptibility and progression on well-defined Polish population. Our investigation revealed that CT individuals in rs1883832 locus of CD40 possessed almost 1.5-fold higher risk for MS than CC individuals (OR = 1.44; 95%CI = 1.03-2.1; p = 0.032), while this risk for TT individuals was almost 2.5-fold higher (OR = 2.36; 95%CI = 1.19-4.78; p = 0.014). Moreover, for the first time, we observed the association of CD40 gene with MS development and progression. We observed that for the rs1883832CC individuals the age at diagnosis was on average 2 years lower than for the rs1883832CT and rs1883832TT individuals (CI95% = -3.69-(-0.29); p = 0.023). Additionally, we detected that individuals with TT and CT genotypes showed lower risk of developing secondary progressive course in comparison to those with CC genotype. For rs1883832TT individuals this risk was 4-fold lower (HR = 0.24; CI95% = 0.10-0.53; p = 0.00062). Despite the fact that CD40-CD40L pathway plays a key role in development of autoimmune diseases, we were not able to detect gene-gene interactions between CD40 and CD40L polymorphisms associated with multiple sclerosis.

Distribution of killer cell immunoglobulin-like receptor genes in Poles.

Killer cell immunoglobulin-like receptors (KIRs) present on natural killer cells and minor subpopulations of T cells recognize class I human leucocyte antigen (HLA) molecules on the surface of target cells. Humans differ by the presence or absence of some KIR genes on their chromosomes. As KIRs are important for the outcome of tissue transplantation (particularly for haematopoietic stem cell transplantation) and possibly for pregnancy and autoimmune diseases, knowledge of the KIR gene distribution in a given human population is of practical value. Therefore, we tested 363 healthy individuals from Western Poland for the presence or absence of KIR genes. Results are compared with those published for other human populations. KIR gene frequencies in Poles are close to these in other Caucasoids but different from those in Asian and African populations, and particularly distant from those in Australian Aborigines.

Distribution of the CTLA-4 single nucleotide polymorphisms CT60G>A and +49A>G in psoriasis vulgaris patients and control individuals from a Polish Caucasian population.

Psoriasis vulgaris is a multifactorial disease with an autoimmune component, and T lymphocytes seem to be involved in its aetiology. CTLA-4 molecule is an important down-regulator of T-lymphocyte activation, and several polymorphisms of the CTLA-4 gene were found to be associated with some autoimmune diseases. We examined whether single nucleotide polymorphisms (SNPs) in the CTLA-4 gene, CT60A>G and +49A>G, are associated with psoriasis vulgaris. Alleles of these two SNPs were determined by the polymerase chain reaction-restriction fragment length polymorphism method. Both the CT60G>A and the +49A>G alleles and genotypes were distributed similarly in patients and controls. Although the two SNPs studied here in Poles were in linkage disequilibrium, all four possible two-locus haplotypes were found, one of them rare; of the remaining three, the haplotype +49G, CT60G was significantly (P = 0.019, OR = 0.58, 95%CI = 0.37-0.91) less frequent in the patient group with disease onset between the ages of 21 and 40 years than in controls and the other patient groups, whereas the frequencies of the other haplotypes were similar in patients and controls. To the authors' knowledge, this is the first study on CTLA-4 CT60 allele frequencies in psoriasis.

Associations of killer cell immunoglobulin-like receptor genes with complications of rheumatoid arthritis.

We investigated whether killer cell immunoglobulin-like receptor (KIR) genes are risk factor(s) for rheumatoid arthritis (RA) and its clinical manifestations. One hundred and seventy-seven RA patients and 243 healthy individuals were tested for the presence of 11 KIR genes using PCR-SSP method. The frequencies of KIRs in patients with RA were similar to the frequencies in controls. However, RA patients positive for KIR2DL3 and negative for KIR2DS3 had earlier disease diagnosis. Additionally, KIR2DL2 and KIR2DS2 were significantly more frequent among RA patients with extra-articular manifestations and in its subgroup with vasculitis than in controls and in patients without these complications. Furthermore, the frequencies of KIR2DS1 and KIR3DS1 were lower in patients without bone erosions compared with healthy individuals. Relationships between the presence or absence of autoantibodies (rheumatoid factor and anti-cyclic citrullinated peptide) and KIR frequencies were also evaluated, but no significant differences were observed. These results suggest that particular clinical manifestations of RA may have different genetic backgrounds with respect to KIR genotype.

Inhibitory and activatory KIR gene frequencies in the Polish population.

Killer cell immunoglobulin-like receptors (KIRs) present on natural killer cells and minor subpopulations of T cells recognize class I human leukocyte antigen (HLA) molecules on the surface of target cells. Human individuals differ by the presence or absence of some KIR genes on their chromosomes (haplotypic polymorphism). As KIRs (especially two-immunoglobulin-domain-like containing, or KIR2D, molecules) are important for the outcome of tissue (particularly for haematopoietic stem cell) transplantation and possibly for pregnancy, the knowledge of KIR gene distribution in a given human population is of practical value. Therefore, we tested 175 healthy individuals from Poland for the presence or absence of these KIR genes which show haplotypic polymorphism and are expressed. Results were compared with those published for other human populations, showing close relations with other Caucasoids.

CTLA-4 gene polymorphisms and natural soluble CTLA-4 protein in psoriasis vulgaris.

CTLA-4 molecule is an important inhibitor of T-lymphocyte activation. Several single nucleotide polymorphisms (SNPs) in the CTLA-4 gene were found, and their associations with many human diseases were described. So far, however, such studies have not been performed in psoriasis vulgaris in Caucasoids. Therefore, we examined the distribution of three CTLA-4 SNPs: -1147C/T, -318C/T and +49 A/G in 116 patients with psoriasis vulgaris and 123 healthy blood donors using the polymerase chain reaction-restriction fragment length polymorphism method. For all three SNPs, the frequencies of alleles, genotypes and three-point haplotypes were very similar in patients and controls, suggesting no contribution of these genetic variants to psoriasis.

Possible association of cytotoxic T-lymphocyte antigen 4 gene promoter single nucleotide polymorphism with acute rejection of allogeneic kidney transplant.

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) molecule is an important inhibitor of T-lymphocyte response. Polymorphisms in the CTLA-4 gene have been described to be associated with numerous autoimmune diseases. However, similar studies in solid organ transplantation have been scarce. Therefore, we examined the distribution of three single nucleotide dimorphisms, namely, -1147T/C, -318C/T, and +49A/G, in two groups of allogeneic kidney graft recipients: (1) those with at least one acute rejection episode ("rejectors"; n = 38) and (2) those with no signs of acute rejection ("nonrejectors"; n = 53). Allele frequencies in both groups of patients were similar in two positions, -1147T/C and +49A/G. However, rejectors showed slight differences from nonrejectors for allele and genotype frequencies in position -318. The -318T allele was two times less frequent among rejectors than nonrejectors, a difference that was close to statistical significance (P = .039; P corrected = .0583), and may reach it when greater numbers of patients are tested.

A novel polymorphism in the cytoplasmic region of the human immunoglobulin A Fc receptor gene.

The Fc receptor for immunoglobulin A (IgA), FcalphaRI, is expressed on several types of myeloid cells, and activates them upon ligand binding. However, binding of IgA to the extracellular domain of the receptor requires previous stimulation of the cell by cytokines, and the cytoplasmic tail of FcalphaRI has been shown to play a role in this. Therefore, polymorphism in this region might affect this process. However, no changes in the amino acid sequence in this region of the FcalphaRI have so far been reported. Here, we describe for the first time a single nucleotide polymorphism in exon 5 of the immunoglobulin A Fc receptor (FCAR) gene leading to a Ser-->Gly substitution at position 248 of the mature FcalphaRI protein. Prediction of structural features suggests some changes that may affect the function of the protein to some extent. However, the Gly248 variant is quite common (4% homozygotes and 38% heterozygotes) in healthy population, suggesting a weak effect, if any, on function, at least in heterozygotes.

Modification of ion channels and calcium homeostasis of basal forebrain neurons during aging.

In this paper we review the last several years of work from our lab with attention to changes in the properties of basal forebrain neurons during aging. These neurons play a central role in behavioral functions, such as: attention, arousal, cognition and autonomic activity, and these functions can be adversely affected during aging. Therefore, it is fundamental to define the cellular mechanisms of aging in order to understand the basal forebrain and to correct deficits associated with aging. We have examined changes in the physiological properties of basal forebrain neurons during aging with whole-cell and single-channel patch-clamp, as well as, microfluorimetric measurements of intracellular calcium concentrations. These studies contribute to the understanding of integration within the basal forebrain and to the identification of age-related changes within central mammalian neurons. Although extensive functional/behavioral decline is often assumed to occur during aging, our data support an interpretation of compensatory increases in function for excitatory amino acid receptors, GABA(A) receptors, voltage-gated calcium currents and calcium homeostatic mechanisms. We believe that these changes occur to compensate for decrements accruing with age, such as decreased synaptic contacts, ion imbalances or neuronal loss. The basal forebrain must retain functionality into late aging if senescence is to be productive. Thus, it is critical to recognize the potential cellular and subcellular targets for therapeutic interventions intended to correct age-related behavioral deficits.

Pharmacological characterization of ionotropic excitatory amino acid receptors in young and aged rat basal forebrain.

Ionotropic glutamate receptors were characterized in acutely dissociated medial septum/nucleus of diagonal band neurons from one- to four-month- and 24-26-month-old male Fischer 344 rats. Whole-cell patch-clamp recordings were used to study glutamate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, kainate and N-methyl-D-aspartate-induced currents. Pharmacological properties of these ionotropic receptors were studied across different age groups by comparing concentration response curves and EC50 for agonist-induced currents, as well as dissociation constants (Kb) for competitive receptor antagonists. Our results suggest that non-N-methyl-D-aspartate receptors on medial septum/nucleus of diagonal band neurons were predominantly of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate type and display biophysical and pharmacological properties similar to other central neurons. However, peak alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate-induced currents were enhanced in aged (35.0+/-4.4 pA/pF) compared to young cells (16.2+/-1.7 pA/pF, P<0.005), and the EC50 shifted to the right (4.4+/-0.6 in young compared to 8.8+/-1.3 microM in aged, P<0.05). The Kb for 6,7-dinitroquinoxaline-2,3-dione inhibition of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate-induced currents likewise shifted to the right (0.16+/-0.02 in young and 0.29+/-0.04 microM in aged, P<0.05) suggesting an age-related decrease in affinity for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors. N-Methyl-D-aspartate-induced currents were generated in standard physiological solutions with the addition of 1 microM glycine and the removal of Mg2+. The N-methyl-D-aspartate responses were predictably modulated by magnesium and glycine, and were antagonized by the competitive antagonist 2-amino-5-phosphonovaleric acid. No age-related change in N-methyl-D-aspartate maximum, EC50, magnesium sensitivity, glycine sensitivity or Kb for 2-amino-5-phosphonovaleric acid was observed. Overall, our results suggest that ionotropic glutamate receptors in the medial septum/nucleus of diagonal band have a similar pharmacological profile compared to glutamate receptors in other brain regions. More importantly, these data suggest that while medial septum/nucleus of diagonal band cells maintain N-methyl-D-aspartate receptors during ageing, a significant increase in current density and decrease in receptor affinity for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors, during this same time period, may provide a mechanism for age-related changes in neuronal plasticity and excitotoxicity in the basal forebrain.

Activation of heteromeric G protein-gated inward rectifier K+ channels overexpressed by adenovirus gene transfer inhibits the excitability of hippocampal neurons.

G protein-gated inward rectifier K+ channel subunits 1-4 (GIRK1-4) have been cloned from neuronal and atrial tissue and function as heterotetramers. To examine the inhibition of neuronal excitation by GIRKs, we overexpressed GIRKs in cultured hippocampal neurons from 18 day rat embryos, which normally lack or show low amounts of GIRK protein and currents. Adenoviral recombinants containing the cDNAs for GIRK1, GIRK2, GIRK4, and the serotonin 1A receptor were constructed. Typical GIRK currents could be activated by endogenous GABAB, serotonin 5-HT1A, and adenosine A1 receptors in neurons coinfected with GIRK1+2 or GIRK1+4. Under current clamp, GIRK activation increased the cell membrane conductance by 1- to 2-fold, hyperpolarized the cell by 11-14 mV, and inhibited action potential firing by increasing the threshold current for firing by 2- to 3-fold. These effects were not found in non- and mock-infected neurons, and were similar to the effects of muscarinic stimulation of native GIRK currents in atrial myocytes. Two inhibitory effects of GIRK activation, hyperpolarization and diminution of depolarizing pulses, were simulated from the experimental data. These inhibitory effects are physiologically important in the voltage range between the resting membrane potential and the potential where voltage-gated Na+ and K+ currents are activated; that is where GIRK currents are outward.

Ethanol inhibition of reduced frequency-dependent rundown of calcium currents in acutely dissociated MS/nDB neurons from chronic in vivo lead-exposed adult rats.

Although it is well known that lead (Pb2+0 acutely blocks voltage-gated calcium currents (VGCCs) in mammalian neurons, little is known about the long-term effects of continuous exposure to this metal on VGCCs. In the present study, the effects of chronic lead exposure on VGCCs (with barium ions as the charge carrier) were studied using whole-cell patch-clamp electrophysiological techniques in acutely dissociated medial septum (MS)/nucleus diagonal band (nDB) neurons. Neither peak, end current amplitudes, nor the current-voltage relationship were affected by chronic lead exposure. However, VGCCs repetitively evoked at frequent 6 s intervals displayed diminished whole-cell current rundown after 2 min of stimulation in cells from chronic Pb-exposed rats compared to cells from control Na-exposed rats. Because rundown after repetitive stimulation at a slower rate (20 s intervals) was not different between Pb-exposed and Na-exposed, reduced rundown at 6 s intervals was probably due to decreased slow inactivation of voltage-gated calcium channels. Interestingly, acute application of 60 mM ethanol reversed the reduced rundown in cells from Pb-exposed rats while having no effect on cells from Na-exposed rats. Clearly, acute ethanol treatment antagonized the effect of chronic lead exposure, unlike the additive interaction we observed previously with synaptic plasticity (Grover and Frye, 1996). Acute application of 1 microM Pb2+ completely blocked VGCCs similarly in neurons from Na-exposed and Pb-exposed rats. These findings do not suggest that major adaptive changes in VGCCs have occurred during chronic in vivo exposure to lead. But, subtle changes in channel efficiency only revealed under conditions of repetitive stimulation may exist, and are reversed by ethanol. These subtle changes may be sufficient to influence neuroplasticity such as LTP.