A comparative study of modulatory interaction between cytokines and apoptotic proteins among Scleroderma patients with and without pulmonary involvement

BACKGROUND

Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are the most eminent forms of pulmonary involvement in Scleroderma. In this study we investigate the interaction between cytokines and apoptotic proteins in treatment naive Scleroderma (SSc) patients with and without pulmonary involvement.

METHODS

Newly diagnosed treatment naïve Scleroderma (SSc) patients (n = 100) and healthy controls (n = 100) were enrolled. Patients were classified as ILD-SSc, PAH-SSc and non-pulmonary SSc (np-SSc). Study variables like mRSS score, autoantibody profile, serum cytokines, serum TGF-β (1,2,3) and apoptotic proteins were assessed for these patients.

RESULTS

Scleroderma patients showed elevated levels of serum cytokines, but significantly lower IL-22 and TGF- β1 when compared to healthy controls (p < 0.05). Apoptotic proteins were significantly elevated among Scleroderma patients, but the patient groups also showed significant lower caspase 1/3/9 levels when compared to healthy controls (p < 0.05). ILD-SSc patients reported higher mRSS score (p = 0.0436) when compared with PAH-SSc and np-SSc. In ILD-SSc patients, finger tightening (p = 0.0481) and calcinosis/lesions (p = 0.0481) were significant clinical presentations whereas, digital ulcers were significantly prominent in np-SSc patients (p = 0.0132). Elevated TGF-β3 levels (p = 0.02) in SSC-ILD and reduced IL-4 levels (p = 0.02) in SSC-PAH were significant cytokines as compared to np-SSc. Significant correlations were obtained among serum cytokines and apoptotic proteins in Scleroderma patients with and without pulmonary involvement. (p < 0.05) CONCLUSION: Our study highlights the correlation between mRSS score, cytokines and apoptotic proteins in SSc patients with pulmonary involvement. A longitudinal follow up in these patients with assessment of these immunological parameters may be helpful in monitoring the disease.

A Clinical Profile of Patients with Hyperuricemia and the Relationship between Hyperuricemia and Metabolic Syndrome: A Cross-sectional Study at a Tertiary Hospital in the Indian Population

INTRODUCTION

Metabolic syndrome is a constellation of interrelated risk factors that increase the risk of cardiovascular diseases (CVD) and diabetes mellitus. The increase in prevalence of hyperuricemia was considered to be directly related to increasing incidence of obesity and Metabolic Syndrome in developing and developed countries. Hyperuricemia is defined as serum uric acid of 6.0mg/dl and 7.0mg/dl for females and males respectively.

AIMS AND OBJECTIVES

To study correlation of hyperuricemia with metabolic syndrome or its components.

MATERIALS AND METHODS

An observational, cross sectional single centre study with 316 patients fulfilling inclusion and exclusion criteria was carried out.

RESULTS

Out of 316 patients, 202 (63.9%) were males and 114 (36.1%) were females. 138(43.7%) were from rural areas and 178 (56.3%) were from urban areas. 126 (39.9%) patients had an active lifestyle and 190 (60.1%) had a sedentary lifestyle. Mean waist circumference among114 females was 82.10 cm and among men was 87.07cm. 113 patients fulfilled the criteria for central obesity with the mean uric acid level of 8.14 mg/dl (p=0.001); Mean uric acid level of patients without central obesity was 7.36 mg/dl. 99 (31.33%) fulfilled the criteria for hypertriglyceridemia with mean s.uric acid level 8.24mg/dl (p=0.0440). 124 had elevated blood pressure with mean s.uric acid 8.28 mg/dl (p=0.004). Patients with normal blood pressure had a mean value of s. uric acid 7.86 mg/dl. 33.44% fulfilled the criteria for metabolic syndrome (41.23%of total females and 32.10% of total males). Odds ratio was 1.28 and 0.864 for females and males respectively.

CONCLUSION

Prevalence of metabolic syndrome in patients with hyperuricemia was 35.4%. More common in females than males. Hyperuricemia is more prevalent in patients with a sedentary lifestyle. Hyperuricemia positively correlates with central obesity, blood pressure, hypertriglyceridemia and hyperglycemia. Hence, it is of utmost importance to screen patients of hyperuricemia for metabolic syndrome or its components to prevent mortality and morbidity associated with CVDs.

Mannose Binding Lectin Levels and its Association with Systemic Lupus Erythematosus Disease Severity: An Indian Report

BACKGROUND

Dysregulated serum levels of Mannan binding lectin (MBL) has a probable role in Systemic Lupus Erythematosus (SLE) pathogenesis.

OBJECTIVE

To evaluate the association between serum MBL levels in SLE patients from western India with the severity of disease Methods: SLE patients (n=70) from Western India were included. Based on MBL levels, patients were classified into four categories, viz. low (&lt;100 ng/ml), mild (100-500 ng/ml), moderate (500-1000 ng/ml) and high (&gt;1000 ng/ml). Correlation of serum MBL levels with disease severity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). MBL levels and circulating immune complex levels were detected by ELISA. C3, C4 and CRP levels were detected by nephelometer.

RESULTS

Serum MBL levels of SLE patients (1954 ± 202.4 ng/ml) was lower than that of healthy controls (2388 ± 205.0 ng/ ml). There was no significant correlation between MBL levels with severity of SLE on the basis of ACR criteria and SLEDAI scores (p&gt; 0.05). No significant difference was observed among MBL levels and SLE patients with (1847 ± 246.7) or without (1900 ± 246.8) Lupus Nephritis. SLE patients without infections (n= 33) had low MBL levels (1700 ± 301.0 ng/ ml) as compared with SLE patients with infection (n= 37) (2189 ± 284.6 ng/ ml) (p=0.30) Conclusion: Present study indicated that low MBL levels were not associated with disease severity, haematological manifestations and infections among SLE patients from Western India.

SorCS2 is required for social memory and trafficking of the NMDA receptor

Social memory processing requires functional CA2 neurons, however the specific mechanisms that regulate their activity are poorly understood. Here, we document that SorCS2, a member of the family of the Vps10 family of sorting receptors, is highly expressed in pyramidal neurons of CA2, as well as ventral CA1, a circuit implicated in social memory. SorCS2 specifically localizes to the postsynaptic density and endosomes within dendritic spines of CA2 neurons. We have discovered that SorCS2 is a selective regulator of NMDA receptor surface trafficking in hippocampal neurons, without altering AMPA receptor trafficking. In addition, SorCS2 regulates dendritic spine density in CA2 neurons where SorCS2 expression is enriched, but not in dorsal CA1 neurons, which normally express very low levels of this protein. To specifically test the role of SorCS2 in behavior, we generated a novel SorCS2-deficient mouse, and identify a significant social memory deficit, with no change in sociability, olfaction, anxiety, or several hippocampal-dependent behaviors. Mutations in sorCS2 have been associated with bipolar disease, schizophrenia, and attention deficient-hyperactivity disorder, and abnormalities in social memory are core components of these neuropsychiatric conditions. Thus, our findings provide a new mechanism for social memory formation, through regulating synaptic receptor trafficking in pyramidal neurons by SorCS2.

Hypervitaminosis D and Cortical Venous Thrombosis; An Unusual Presentation

Hypervitaminosis D is rare but potentially serious condition. It occurs most commonly due to excess doses of vitamin D supplementation, most commonly intramuscular. Here we report a case of iatrogenic hypervitaminosis D who presented with altered sensorium, cortical venous thrombosis and acute renal failure.

Clinical implications of IL-10 promoter polymorphisms on disease susceptibility in Indian SLE patients

Single nucleotide polymorphisms in cytokine genes including interleukin-10 have been described to play a vital role in the overall pathogenesis of systemic lupus erythematosus. However, due to a lack of evidence from the Indian population, this study was conducted to analyse the possible influence of interleukin-10 promoter polymorphisms over the disease susceptibility, serum interleukin-10 level and clinical manifestations of the disease in Indian systemic lupus erythematosus patients. In total, 200 systemic lupus erythematosus patients and 201 controls were recruited under this study. Genotyping of interleukin-10 (−1082A/G; −819T/C and −592C/A) polymorphisms was done by direct DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism methods respectively. Serum interleukin-10 levels were measured by multiplex assay. Interleukin-10 −1082G and −592A allele frequencies were significantly increased in systemic lupus erythematosus patients (corrected p value <0.05). Also, combined −1082AG+GG, −819TC+CC and −592CA+AA genotype frequencies were significantly increased in the patient group. A higher trend of association between −1082AG+GG genotype frequency was observed in patients with serositis (odds ratio = 2.7, p = 0.0233, corrected p value = 0.2097). Serum interleukin-10 levels were significantly higher in systemic lupus erythematosus patients (4.3 ± 3.1 pg/ml) than controls (2.6 ± 1.4 pg/ml) ( p < 0.0001). Furthermore, interleukin-10 levels were positively correlated with disease activity ( p = 0.39, p < 0.0001). The frequency of the GCA (−1082, −819, −592) haplotype was significantly higher in systemic lupus erythematosus patients (10.6%) than controls (1.6%) (odds ratio = 5.4, p = 0.0330). Moreover, ACC, GCC and GCA haplotypes were found to be strongly associated with serositis. However, the frequency of the ACC haplotype was significantly higher in patients with neurologic involvement (odds ratio = 14.9, corrected p value <0.001). Thus, interleukin-10 promoter polymorphisms suggest they have a proactive role in increased susceptibility to the disease among Indian systemic lupus erythematosus patients.

Impact of functional IL-18 polymorphisms on genetic predisposition and diverse clinical manifestations of the disease in Indian SLE patients

Several studies have demonstrated associations between interleukin-18 polymorphisms and risk of systemic lupus erythematosus in different populations except one of Indian origin. We therefore investigated for the influence of interleukin-18 (-1297T/C, -607A/C, -137G/C; + 105A/C) polymorphisms on genetic susceptibility and clinical expression of the disease in Indian systemic lupus erythematosus patients. A total of 200 systemic lupus erythematosus patients and 201 controls were recruited. Genotyping of interleukin-18 polymorphisms were performed by polymerase chain reaction-restriction fragment length polymorphism. Serum interleukin-18 levels were measured by enzyme-linked immunosorbent assay. Interleukin-18 (-1297T/C; -137G/C) polymorphisms showed significant association with genetic susceptibility to the disease in our systemic lupus erythematosus cohort. Stratification analysis revealed -1297CC and -1297C associated with renal involvement (odds ratio = 3.4, correcting p value = 0.0207), (odds ratio = 2.0, correcting p value = 0.0054) respectively. Additionally, -1297C allele frequency was significantly increased in patients with anti-nucleosome antibody (odds ratio = 2.1, correcting p value = 0.0301). Haplotype analysis showed CC haplotype strongly associated with serositis (odds ratio = 9.1, correcting p values = 0.0009) and neurologic involvement (odds ratio = 9.3, correcting p value = 0.0018). We reported a 2.7-fold increase in serum interleukin-18 levels in patients (511.5 ± 242.3 pg/ml) compared to controls (189.4 ± 80.8 pg/ml) ( p < 0.0001). Furthermore, interleukin-18 levels were positively correlated with disease activity ( r = 0.548, p = 0.0001) and renal involvement in the patients with lupus nephritis ( r = 0.569, p < 0.0001). In summary, interleukin-18 polymorphisms elucidated in this study appear to confer genetic susceptibility to the disease and are associated with renal, serositis and neurologic involvement in Indian systemic lupus erythematosus patients.

Adipokine interactions promote the pathogenesis of systemic lupus erythematosus

BACKGROUND

Adipokines are chemical mediators released from adipose tissue involved in regulation of appetite, insulin sensitivity, immune system and inflammatory responses. Adipokines contributes to low grade inflammatory response in autoimmune disease like Systemic Lupus Erythematosus (SLE) but the pathophysiology is yet not clear. The aim of this study is to understand role of adipokine interactions in SLE disease pathogenesis.

METHODS

Sixty newly diagnosed treatment naïve SLE patients fulfilling the ACR criteria and forty age-sex matched healthy subjects were enrolled in thiscase-control study. Disease activity in SLE patients was evaluated using SELENA-SLEDAI. Array of adipokines, C1q circulating immune complexes (C1q-CIC), anti-C1q, anti-ribososmal P0 (anti-RibP0) and anti-mitochondrial antibodies (AMA) levels were detected by ELISA. Antinuclear antibodies (ANA) and anti-dsDNA autoantibodieswere detected by Indirect Immunofluorescence (IIF), while antigen specificities were detected by Immunoassay blot. Serum levels of C3 and C4 complement factors were assessed by nephlometer.

RESULTS

Statistically significant elevation in progranulin, adipsin and resistin levels was seen among SLE patients when compared to healthy controls (p < 0.0001). Leptin and omentin levels were significantly reduced in SLE patients (p < 0.0001). There was no statistically significant difference in serum adiponectin, chemerin and visfatin levels when these two groups were compared (p > 0.05). Adiponectin, adipsin and resistin levels were elevated in SLE patients with renal manifestations (p < 0.05). Reduced leptin levels were significantly associated with presence of renal manifestations (p < 0.05). Adiponectin levels positively correlated with disease activity (r = 0.294, p = 0.027) whereas negatively correlated with C3 levels (r = -0.439, p = 0.0007). A positive correlation was observed between hypocomplementemia and leptin levels (p < 0.05). Leptin levels were negatively correlated with disease activity, anti-dsDNA, C1q-CIC and anti-C1q levels (p < 0.05). A significant positive correlation was observed between progranulin levels and anti-ribosomal P0 antibodies (r = 0.499, p < 0.0001).

CONCLUSION

Adipokines levels and associated clinical manifestations suggest involvement of adipokines in disease pathogenesis of SLE. SLE disease activity and complement components may suggest regulatory effect of adipokines (adiponectin and leptin) on disease pathogenesis. Further studies on adipokines in SLE patients with renal manifestations may propose them as prognostic markers in renal damage.

TRIAL REGISTRATION

NA.

Catalytic antibodies in patients with systemic lupus erythematosus

OBJECTIVE

Antibodies with catalytic (hydrolytic) properties to DNA or RNA have been reported in systemic lupus erythematosus (SLE). However, it is well known that ethnicity plays an important role in the presentation of SLE and severity of the disease; hence, these data may not truly represent a general feature of all SLE patients. Therefore, we have analyzed the hydrolyzing activity of immunoglobulin G (IgG) of SLE patients from the Indian population with an aim to decode whether the catalytic antibody response represents part of an active disease process.

METHODS

IgGs were isolated from the sera of 72 consecutive patients diagnosed with SLE. As a control, IgGs from healthy donors were used. The catalytic activity of IgG was measured by PFR-MCA and affinity-linked oligonucleotide nuclease assay.

RESULTS

IgGs from patients with SLE from the Indian subcontinent displayed significantly higher hydrolysis rates of both the surrogate substrate, PFR-MCA, and the DNA than IgG from healthy individuals. Intergroup comparisons of the IgG-PFR-MCA interactions with clinical manifestations of the disease demonstrated a significantly increased level of hydrolysis among the patients with renal involvement who tested positive for anti-dsDNA antibodies. The PFR-MCA hydrolysis also appears to be associated with the active disease (p=0.0988, vs. inactive group).

CONCLUSION

The prevalence of catalytic antibodies represents a general feature of SLE patients, irrespective of their origin.

Association of clinical and serological parameters of systemic lupus erythematosus patients with Epstein-Barr virus antibody profile

Epstein-Barr viral infection is one of the known environmental factors involved in development of Systemic Lupus Erythematous (SLE). Though not much is known about the exact role of Epstein-Barr virus (EBV) in SLE pathogenesis, the theory of switching of lytic and lysogenic cycles of EBV in memory B cells fits well with the periods of waning disease activity and intermittent flares in SLE patients. In this study, we investigate the association of EBV antibody profile with clinical and serological parameters in SLE. Eighty-seven clinically diagnosed SLE patients fulfilling the American College of Rheumatology (ACR) classification criteria and fifty healthy individuals were enrolled in this case control study. Anti-VCA IgM, anti-VCA IgG, and anti-EBNA IgG were detected by ELISA technique. Antibodies concentrations between two groups were compared using Mann-Whitney whereas the difference in categorical data was compared using Chi-square considering statistical significance at P < 0.05. This study demonstrated a significant increase in EBV VCA-IgG, VCA-IgM, and EBNA-IgG antibodies levels of SLE patients when compared to healthy controls (P < 0.05). High seroprevalence was seen in both the study groups for EBV VCA-IgG and EBNA-IgG antibodies when compared to VCA-IgM antibodies. A significant increase was noted in the anti-VCA-IgG levels with dsDNA autoantibody positivity (P < 0.05). Though there was no significant association between EBV antibody profile and clinical manifestations, 100% seropositivity for anti-VCA-IgG was seen in SLE patients with renal manifestations. Association of anti-VCA IgG levels with presence of anti-dsDNA antibodies suggests a possible role of EBV as an environmental trigger in pathogenesis of SLE.

Congenital Adrenal Hyperplasia with 11-Beta Hydroxylase Deficiency with Testicular Adrenal Rest Tumour

Congenital adrenal hyperplasia refers to the non-malignant enlargement of adrenal gland tissue as a result of deficiency of one of several enzymes involved in adrenal hormone synthesis, secondary to a genetic mutation. 11 - Beta hydroxylase is one such enzyme, and its deficiency is a rare cause of Congenital Adrenal Hyperplasia. We describe the case of an 18-year old man who presented to us with an acute right ganglio-capsular bleed, hypertension and bilateral scrotal swelling. Investigations revealed hypokalemia, and normal renal and cardiac functions. Furthermore, sex hormone levels were found to be markedly raised, and Renin to Aldosterone ratio was also deranged. CT imaging of the adrenals confirmed hyperplasia, and ultrasound of the testes confirmed Testicular Adrenal Rest tumour, a rare finding. His condition improved significantly with treatment, and he is currently undergoing physical and occupational rehabilitation. Our case highlights the importance of evaluation of hypertension in young patients and a high degree of suspicion for rarer causes.

Oculo-otological Manifestations in a Case of Granulomatosis with Polyangiitis

A 44 year old lady presented with acute onset of loss of vision in the right eye and cough with mucopurulent expectoration for two months. Ophthalmic examination revealed central retinal artery occlusion (CRAO). Chest radiograph showed multiple cavitatory nodules with fluid levels. Sputum was negative for AFB and ANCA was strongly positive suggestive of a diagnosis of Granulomatosis with Polyangiitis (GPA). Within the next few weeks the patient had rapid detenoration due to left eye CRAO, progressive bilateral hearing loss, facial palsy and retro orbital mass. The aggressive disease responded well to steroids and cyclophosphamide.

A Comparitive Study of Anticardiolipin Antibodies among Systemic Lupus Erythematosus Patients from Western and Eastern India

INTRODUCTION

Anti-phospholipid antibodies (APA) like anticardiolipin antibodies (ACA) are important cause of venous and arterial thrombosis and other occlusive vascular diseases. Prevalence of these antibodies in SLE patients at the time of diagnosis is not known in Indian SLE patients. This study was conducted to evaluate the prevalence of ACA in SLE patients from Eastern and Western India and to correlate them with disease activity.

MATERIAL AND METHODS

Seventy SLE patients from Assam Medical College, Dibrugarh, Assam and 85 SLE patients from Rheumatology Department, KEM Hospital, Mumbai were studied. SLE disease activity was evaluated by SLE Disease Activity Index (SLEDAI) score at the time of evaluation. All patients studied were in an active stage of disease.

RESULTS

Demographic data showed significant variations in the clinical manifestations of SLE between two regions. Renal manifestations were higher (42.9%) among SLE patients from Eastern region as compared with 37.6% patients from Western region. These patients were categorized as Lupus Nephritis (LN) and patients that did not show any renal manifestations were categories as non-LN. ACA to IgG and IgM subclasses were tested by ELISA. IgGACA positivity was 20%, 12.9% and IgM-ACA positivity was 18.6%, 12.9% where asIgG + IgM ACA positivity as found in 12.9%, 3.5% patients respectively among SLE patients from Eastern and Western India.

CONCLUSIONS

ACA positivity was higher among LN patients from Eastern India whereas the same was higher among non-LN patients from Western India. Hence detection of ACA alongwith associated clinical manifestations were helpful to evaluate their possible association with disease severity in SLE patients. A long term follow up of patients having ACA antibodies without thrombotic event is needed to detect their possible thrombotic event in future along with their clinical presentation from these two different geographic regions from India.

Recurrent Seizures Due to Pancreatic Insulinoma

We present the case of a 70 year old man who was admitted with history of generalized tonic clonic seizures on and off since 6 years in spite of being on regular therapy with anticonvulsants. Patient was found to have hypoglycemia and was evaluated for same. He was diagnosed to have endogenous hyperinsulinemia due to pancreatic insulinoma. Patient underwent enucleation of tumor and was relieved of his symptoms.

Association of Serum Ferritin Levels with Hematological Manifestations in Systemic Lupus Erythematosus Patients from Western India

OBJECTIVE

To identify the hematological manifestations and its association with serum ferritin levels in SLE patients from Western India.

METHODS

Ninety clinically diagnosed SLE patients fulfilling ACR criteria were included. Disease activity was assessed at the time of evaluation using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Sera were tested for serum ferritin levels by ELISA (Calbiotech, USA). Autoantibodies such as ANA, anti-dsDNA by indirect immunofluorescence test (IFA- Bio-Rad, USA) and anti-cardiolipin antibodies (ACA) to IgG and IgM isotypes and Anti-β2 GP antibodies to IgG and IgM isotypes were detected by ELISA using commercially available kits (Euroimmun, Lubeck, Germany).

RESULTS

Out of 90 SLE patients studied, 41 patients (45.6%) showed hematological abnormalities, where anemia (82.9%), leucopenia (26.8%), autoimmune hemolytic anemia (AIHA) (14.6%) and idiopathic thrombocytopenic purpura (ITP) were noted in (34.1%) patients. Mean±SD serum ferritin levels among SLE patients were 270.2±266.0 ng/ml as compared to 29.0±15.8 ng/ml healthy normal controls (p<0.0001). A positive correlation between serum ferritin levels and SLEDAI scores (r= 0.2640, p=0.0124) and anti-dsDNA positivity was noted (r=0.32, p<0.0001). Serum ferritin levels were negatively correlated with hemoglobin levels (r=-0.5964, p=0.0001), WBC count (r=-0.1705, p=0.2316), platelet count ((r=-0.1701, P=0.2375), C3 levels (r=-0.4417, p=0.0034) and C4 levels (r=-0.0363, p=0.8215).

CONCLUSIONS

Serum ferritin is an excellent marker of SLE which can be used for an evaluation of disease activity particularly in active stage of the disease mainly in patients having hematological and renal manifestations.

Mannose binding lectin (MBL) 2 gene polymorphism & its association with clinical manifestations in systemic lupus erythematosus (SLE) patients from western India

Background & objectives:

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by production of autoantibodies. Mannose binding lectin (MBL) is an important element of the innate defense system. The present study was undertaken to determine whether variant alleles in MBL2 gene were associated with disease severity in SLE patients.

Methods:

The MBL alleles [-550, -221, +4, Codon 52, Codon 54 and Codon 57] were studied by PCR- RFLP (restriction fragment length polymorphism) method in 100 SLE patients fulfilling ACR (American College of Rheumatology) criteria along with 100 healthy controls. SLE disease activity was evaluated using SLE Disease Activity Index (SLEDAI) score.

Results:

Homozygosity for MBL variant allele (O/O) was observed in 24 per cent of the SLE patients compared to 16 per cent of the normal controls, while no difference was found for heterozygosity (A/O) (37 vs 35%). A significant difference was reported in incidence of double heterozygosity for mutant allele B and D (B/D) among SLE patients as against control group (P = 0.015). MBL genotypes did not show any association with renal involvement.

Interpretation & conclusions:

In this study from western India, MBL gene polymorphism showed an influence as a possible risk factor for susceptibility to SLE, but had no direct effect on disease characteristics. Further studies need to be done on a larger number of SLE patients in different regions of the country.

Cereblon, a molecular target of lenalidomide (IMiDs), negatively regulates T cell activation (IRM7P.715)

Thalidomide analogs classified as immunomodulatory drugs (IMiDs) are rapidly emerging T-cell stimulants for the treatment of cancer. Cereblon, an E3-Ub ligase receptor with no known immune regulatory function, is the first identified target of IMiDs. The drug is hypothesized to have antagonistic properties by interfering with substrate recruitment to the thalidomide-binding domain in cereblon, and agonistic activity through an exposed ring that may recruit new proteins to the Ub complex. To explore this further at the molecular level, we studied immune regulation in cereblon deficient mice (crbn-/-), which exhibited an expanded white blood cell and neutrophil compartment, and higher numbers of peripheral and splenic lymphocytes. Mature crbn-/- T cells were capable of proliferation and IL-2 production following CD3 ligation in the absence of CD28 co-ligation. This positively associates with proximal phosphorylation events including pZap70, pAKT, pro-survival Bcl-XL and Bcl-2 protein expression, and corresponds with decreased pro-apoptotic proteins Bim, Bad, and Bax. Consistent with this data in a lethal graft-versus-host (GVHD) model, MHC-class I mismatched T cells from crbn-/- mice showed shortened post-transplant survival, greater weight-loss, and higher IFN-γ compared to transplanted wild-type T-cells. These data suggest that native targets of cereblon restrain the activation threshold of T-cells and that IMiD-associated blockade of cereblon leads to T-cell potentiation.

A case report of hemophagocytic lymphohistiocytosis (HLH)

Hemophagocytic lymphohistiocytosis (HLH), is an uncommon, life-threatening hyperinflammatory syndrome caused by severe hypercytokinemia with excessive activation of lymphocytes and macrophages due to a highly stimulated but ineffective immune process. We report a case of Hemophagocytic Lymphohistiocytosis in a 15 year old boy presenting with fever, lymphadenopathy and pancytopenia due to infection caused by Klebsiella Pneumoniae and Acinetobacter.

Cav1.2 and Cav1.3 L-type calcium channels regulate dopaminergic firing activity in the mouse ventral tegmental area

Dopaminergic projections from the ventral tegmental area (VTA) constitute the mesolimbocortical system that underlies addiction and psychosis primarily as a result of increased dopaminergic transmission. Dopamine release is spike dependent. L-type calcium channels (LTCCs) play an important role in regulating firing activities, but the contribution of specific subtypes remains unclear. This article describes different functions of Cav1.2 and Cav1.3 subtypes in regulating firing properties with two transgenic mouse strains. For basal firing, Cav1.3-deficient (Cav1.3(-/-)) mice had a lower basal firing frequency. The dihydropyridine (DHP) channel blocker nifedipine reduced single-spike firing in mice expressing DHP-insensitive Cav1.2 channels (Cav1.2DHP(-/-) mice), confirming the significant contribution from the Cav1.3 subtype in basal firing. Moreover, the DHP channel activator (S)-(-)-Bay K8644 and the non-DHP channel activator FPL 64176 converted firing patterns from single spiking to bursting in Cav1.2DHP(-/-) mice. Nifedipine inhibited burst firing induced by both activators, suggesting that Cav1.3 also serves an essential role in burst firing. However, FPL 64176 also induced bursting in Cav1.3(-/-) mice. These results indicate that the Cav1.3 subtype is crucial to regulation of basal single-spike firing, while activation of both Cav1.2 and Cav1.3 can support burst firing of VTA neurons.

Anti-C reactive protein antibodies in Indian patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by over production of autoantibodies. C-reactive protein (CRP) is a phylogenetically highly conserved plasma protein that participates in the systemic response to inflammation. Anti-CRP antibodies might have biological functions of pathogenetic interest in SLE. We evaluated anti-CRP antibodies in Indian SLE patients and their association with anti-dsDNA antibodies and complement levels (C3 and C4). One hundred SLE patients diagnosed according to the American College of Rheumatology criteria were included. Disease activity was assessed using SLE disease activity index (SLEDAI). Anti-CRP autoantibodies were detected by enzyme linked immunosorbent assay. Anti-dsDNA antibodies were detected by indirect immunofluroscence test (Euroimmun Lubeck, Germany). High sensitivity CRP and complement levels (C3, C4) were detected using a Nephelometer. (BN ProSpec, Dade Behring, Germany). Anti-CRP antibodies were detected in 26% of SLE patients. Mean age of disease onset among anti-CRP positives was 22.4 ± 7.5, and 26.6 ± 9.3 years among anti-CRP negatives (P > 0.05). Anti-dsDNA positivity was significantly higher among anti-CRP positives (32.7%) as compared to anti-CRP negatives (16%) (P = 0.00519). No statistically significant difference was observed in SLEDAI scores of anti-CRP positive group and anti-CRP negative group (P > 0.05). We observed a positive correlation between anti-CRP antibodies and anti-dsDNA antibodies.

Cereblon is a novel E3 ubiquitin ligase regulator of CD28 signaling in T cells (P1007)

E3 ubiquitin ligases (E3-UbL) regulate clonal anergy and immune self-tolerance. Of the known regulators, c-Cbl and Cbl-b regulate T-cell growth factor production and proliferation induced by IL-2 through the CD28 pathway. Investigations of immunomodulatory (IMiDsTM) drugs lenalidomide (LEN) and thalidomide in myelodysplastic syndrome and multiple myeloma show that these analogs are capable of activating T-cells in the absence of co-stimulation and reverse T-cell anergy. LEN increased IL-2 production (p&lt;0.001), proliferation (p&lt;0.001), and pCREB promoter binding in primary human T-cells after TCR stimulation alone without CD28-receptor ligation. Comparing LEN-induced response in sorted human CD28+CD8+ and CD28-CD8+ T-cells and in CD28 shRNA knock-down T-cells indicates that LEN acts to directly potentiate receptor function dependent on CD28 expression. A landmark study identified cereblon (CRBN), a RING-domain E3-UbL as the primary target of thalidomide. CRBN has also been shown to mediate LEN immunomodulatory activity in vitro. To examine the effect of CRBN on CD28 signaling, germ-line CRBN knock-out mice (crbn-/-) were studied and found to have normal numbers of mature T-cells, normal naïve and memory compartmentalization, and normal proliferative response, but increased contextual activation of IL-2 in the absence of CD28 ligation. These results reveal a novel E3-UbL regulator involved in CD28 signaling with importance in anti-tumor immunity.

Rickettsial fever presenting with isolated third nerve palsy

Rickettsial fevers are known to have neurological involvement, mostly in the form of meningoencephalitis. Focal neurodeficits, including isolated cranial nerve palsies have been rarely reported. We hereby report a case of a 25 year old man who presented to us with high grade fever caused by rickettsia and left sided partial third cranial nerve palsy. He responded to doxycycline.

A study on anti-mannose binding lectin (anti-MBL) antibodies and serum MBL levels in Indian systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by systemic inflammation and autoantibody production. Anti-MBL autoantibodies have been studied in SLE for their possible effect on MBL levels and functional activity. This study aimed at detection of anti-MBL autoantibodies in Indian SLE patients and evaluates their relationship with related immunological parameters. Two hundred diagnosed SLE patients from Western India were included in the study where 87 patients were lupus nephritis (LN) (43.5 %) and remaining (56.5 %) were non-LN. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Anti-MBL autoantibodies to IgG and IgM isotypes, anti-C1q autoantibodies, MBL levels and circulating immune complex levels were detected by ELISA. C3, C4 and CRP levels were detected by nephelometer. Anti-MBL autoantibodies were detected in 52 % SLE patients, where 55 % had IgG-anti-MBL, 33.8 % had IgM-anti-MBL and 11.3 % had both subclasses. Low MBL levels were present in 64.4 % anti-MBL positives as compared with 61.5 % in anti-MBL negatives. Among anti-MBL positives, 74 % had anti-C1q antibodies, whereas 41.7 % of anti-MBL negatives had anti-C1q autoantibodies (p = 3.45E06). An inverse correlation was observed between serum MBL and CIC levels. A statistically significant difference was noted between anti-MBL positives and anti-MBL negative patients with hsCRP levels (p = 0.002). Occurrence of infections was higher among anti-MBL positives (65 %) as compared with anti-MBL negatives (35 %). The difference between SLEDAI scores among anti-MBL positive and negative groups was statistically insignificant. Anti-MBL autoantibodies in SLE patients can influence functional activity of MBL and have a significant role in SLE disease pathogenesis.

Anti-C1q antibodies and their association with complement components in Indian systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease, characterized by immune complex formation and systemic inflammation. Complement components such as C1q and mannose-binding lectin (MBL) play an important role in the clearance of immune complexes. Anti-C1q antibodies are associated with lupus nephritis and reduced levels of the complement components. The objective of this study was to detect anti-C1q antibodies in SLE patients and to evaluate their association with the complement components. Sixty SLE patients were included, of whom 75% had lupus nephritis (LN) and 25% were without renal manifestations (non-LN). The disease activity was assessed at the time of evaluation by the systemic lupus erythematosus disease activity index (SLEDAI). Anti-C1q antibodies, circulating immune complexes, and serum MBL levels were detected by enzyme-linked immunosorbent assay. The anti-C1q antibody prevalence was 58.3%. The LN patients showed 60% anti-C1q positivity with a higher percentage in membranoproliferative glomerulonephritis patients (51.9%). Anti-dsDNA positivity was slightly higher among the anti-C1q positives than in the anti-C1q negatives (65.7% vs. 60%). A higher percentage of reduced C3 and C4 levels was noted among the anti-C1q positives. The LN patients showed a higher percentage of low MBL levels among anti-C1q negatives than in the anti-C1q positives (61.1% vs. 55.6%). Non-LN patients showed a higher percentage of low MBL levels among anti-C1q positives than among anti-C1q negatives (87.5% vs. 57.1%). Anti-C1q antibodies were found in both LN and non-LN patients, but there was no correlation with the clinical severity of the disease.

Disseminated melioidosis presenting as septic arthritis

Melioidosis is an infection caused by Burkholderia pseudomallei. The disease is known as a remarkable imitator due to the wide and variable clinical spectrum of its manifestations. Septic arthritis is rare but well-recognized manifestation of this disease. We report a case of melioidosis in a 52 year male with uncontrolled diabetes mellitus (DM) presenting with a rare combination of septic arthritis and abscesses in the chest wall, liver and subcutaneous tissue. The patient responded to prolonged treatment of intravenous ceftazidime followed by oral co-trimoxazole.

Dengue fever evolving into systemic lupus erythematosus and lupus nephritis: a case report

Dengue viremia may be the trigger for immune complex formation in patients who are predisposed to developing autoimmune disease. We report a rare case of dengue virus infection evolving into systemic lupus erythematosus (SLE) and lupus nephritis. To the best of our knowledge this is the first case of dengue fever evolving into lupus nephritis. A 22 year old female presented with having had high grade fever, skin rash, breathlessness, retro-orbital pain, abdominal pain, arthralgias and myalgias for 10 days. She tested positive for dengue immunoglobulin M (IgM). She was given supportive treatment and was subsequently discharged. Four weeks later she developed recurrent fever, arthralgia, rash and anasarca. She was suspected as having SLE with active lupus nephritis. Antinuclear antibody (ANA), and anti double stranded deoxyribonucleic acid (anti dsDNA) titers were positive and complements were low. Renal biopsy showed diffuse proliferative glomerulonephritis grade IV. She was treated with steroids and immunosuppressants to which she responded. Dengue viremia incites antibody production, which if excessive causes deposition of viral antigen-antibody immune complexes. This could possibly lead to renal tubular damage and glomerulonephritis in susceptible individuals. Dengue fever leading to development of glomerulonephritis is rarely seen. Our patient developed dengue fever and after a month presented with manifestations of SLE and lupus nephritis. Both dengue fever and SLE have common manifestations of fever, arthralgia, rash, leucopenia with thrombocytopenia and serositis. Bacterial and viral infections may act as a 'trigger' for starting or relapsing lupus activity in genetically predetermined individuals. In our case it may be possible that dengue virus could have triggered a dysfunctional immune response, resulting in the developing of autoimmunity and SLE with lupus nephritis.

Cav 1.3 L-type Ca ( 2+) channels mediate long-term adaptation in dopamine D2L-mediated GluA1 trafficking in the dorsal striatum following cocaine exposure

AMPA receptor (AMPAR) plasticity at glutamatergic synapses in the mesostriatal dopaminergic pathway has been implicated in persistent cocaine-induced behavioral responses; however, the precise mechanism underlying these changes remains unknown. Utilizing cocaine psychomotor sensitization in mice we find that repeated cocaine results in a basal reduction of Ser 845 GluA1 and cell surface GluA1 levels in the dorsal striatum (dStr) following a protracted withdrawal period, an adaptation that is dependent on Cav 1.3 channels but not those expressed in the VTA. We find that the basally-induced decrease in this phosphoprotein is the result of recruitment of the striatal dopamine D2 pathway, as evidenced by enhanced levels of D2 receptor (D2R) mRNA expression and D2R function as examined using the D2R antagonist, eticlopride, as well as alterations in the phosphorylation status of several downstream molecular targets of D2R's, including CREB, DARPP-32, Akt and GSK3β. Taken together with our recently published findings examining similar phenomena in the nucleus accumbens (NAc), these results underscore the utilization of divergent molecular mechanisms in the dStr, in mediating cocaine-induced persistent behavioral changes.

Mycotic aneurysm of the popliteal artery due to infective endocarditis

Mycotic aneurysm (MA) is an infrequent complication of infective endocarditis (IE), reported in 3 to 15% of the patients with IE. The commonest site for such aneurysm is intracranial vessels (65%) followed by abdominal and then the peripheral vessels. We describe a case of 32 year old man with recently diagnosed rheumatic heart disease and mitral regurgitation. He had infective endocarditis (IE) and developed a large mycotic popliteal artery aneurysm (MPAA) and a small profunda femoris arterial aneurysm (PFAA) while he was on antibiotic therapy. The patient was successfully treated with prolonged antibiotic therapy and embolisation of the MPAA while PFAA was managed conservatively.

Augmented Constitutive CREB Expression in the Nucleus accumbens and Striatum May Contribute to the Altered Behavioral Response to Cocaine of Adult Mice Exposed to Cocaine in utero

Neuroadaptations occurring in the mesolimbic dopamine pathway following recurrent exposure to drugs of abuse have been correlated with a behavioral phenomenon known as behavioral sensitization. We have developed an animal model of prenatal cocaine exposure and, using a postnatal sensitization protocol, have examined the subsequent sensitivity of offspring to cocaine. Pregnant Swiss Webster dams were injected twice daily from embryonic day 8 to 17, inclusive, with cocaine (COC40: administered cocaine HCl at a dose of 40 mg/kg/day, and COC20: administered cocaine HCl at a dose of 20 mg/kg/day), or saline (SAL). The SPF40 group (saline pair-fed), a nutritional control group, was 'pair-fed' with COC40 dams. Activity was recorded for 30 min during a 3-day saline habituation, a 14-day 'initiation' phase, when animals received cocaine (15 mg/kg) or saline every other day, and following a 21-day 'withdrawal' period when all mice were challenged with cocaine. COC40 offspring, as compared with SAL controls, did not habituate to a novel environment, demonstrated increased cocaine-induced stereotypy on Coc 1 (first cocaine injection), and blunted locomotor sensitization on challenge as measured by the percentage of each animal's baseline locomotion. Tissue samples of the nucleus accumbens (NAc) and striatum (Str) of all four prenatal treatment groups were examined to determine whether alterations in the transcription factor CREB or glutamate receptor subunit, GluR1, induced by prenatal cocaine treatment may have contributed to the altered behavioral responses. Immunoblot quantitation revealed significantly increased constitutive CREB expression in the NAc and Str of COC40 mice as compared with SAL controls. Such alterations in constitutive CREB levels may contribute to some of the behavioral differences reported in adult mice exposed to cocaine in utero.

L-type Ca2+ channels mediate adaptation of extracellular signal-regulated kinase 1/2 phosphorylation in the ventral tegmental area after chronic amphetamine treatment

L-type Ca2+ channels (LTCCs) play an important role in chronic psychostimulant-induced behaviors. However, the Ca2+ second messenger pathways activated by LTCCs after acute and recurrent psychostimulant administration that contribute to drug-induced molecular adaptations are poorly understood. Using a chronic amphetamine treatment paradigm in rats, we have examined the role of LTCCs in activating the mitogen-activated protein (MAP) kinase pathway in the ventral tegmental area (VTA), a primary target for the reinforcing properties of psychostimulants. Using immunoblot and immunohistochemical analyses, we find that in chronic saline-treated rats a challenge injection of amphetamine increases phosphorylation of MAP [extracellular signal-regulated kinase 1/2 (ERK1/2)] kinase in the VTA that is independent of LTCCs. However, in chronic amphetamine-treated rats there is no increase in amphetamine-mediated ERK1/2 phosphorylation unless LTCCs are blocked, in which case there is robust phosphorylation in VTA dopamine neurons. Examination of the expression of phosphatases reveals an increase in calcineurin [protein phosphatase 2B (PP2B)] and MAP kinase phosphatase-1 (MKP-1) in the VTA. Using in situ hybridization histochemistry and immunoblot analyses, we further examined the mRNA and protein expression of the LTCC subtypes Ca(v)1.2 and Ca(v)1.3 in VTA dopamine neurons in drug-naive animals and in rats after chronic amphetamine treatment. We found an increase in Ca(v)1.2 mRNA and protein levels, with no change in Ca(v)1.3. Together, our results suggest that one aspect of LTCC-induced changes in second messenger pathways after chronic amphetamine exposure involves activation of the MAP kinase phosphatase pathway by upregulation of Ca(v)1.2 in VTA dopaminergic neurons.

L-type Ca2+ channel blockers promote Ca2+ accumulation when dopamine receptors are activated in striatal neurons

Dopamine (DA) receptor-mediated signal transduction and gene expression play a central role in many brain disorders from schizophrenia to Parkinson's disease to addiction. While trying to evaluate the role of L-type Ca2+ channels in dopamine D1 receptor-mediated phosphorylation of the transcription factor cyclic AMP response element-binding protein (CREB), we found that activation of dopamine D1 receptors alters the properties of L-type Ca2+ channel inhibitors and turns them into facilitators of Ca2+ influx. In D1 receptor-stimulated neurons, L-type Ca2+ channel blockers promote cytosolic Ca2+ accumulation. This leads to the activation of a molecular signal transduction pathway and CREB phosphorylation. In the absence of dopamine receptor stimulation, L-type Ca2+ channel blockers inhibit CREB phosphorylation. The effect of dopamine on L-type Ca2+ channel blockers is dependent on protein kinase A (PKA), suggesting that protein phosphorylation plays a role in this phenomenon. Because of the adverse effect of activated dopamine receptors on L-type Ca2+ channel blocker action, the role of L-type Ca2+ channels in the dopamine D1 receptor signal transduction pathway cannot be assessed with pharmacological tools. However, with antisense technology, we demonstrate that L-type Ca2+ channels contribute to D1 receptor-mediated CREB phosphorylation. We conclude that the D1 receptor signal transduction pathway depends on L-type Ca2+ channels to mediate CREB phosphorylation.

Clinical utility of screening for antinuclear antibodies by enzyme immunoassay--a preliminary study

AIMS OF THE STUDY

To evaluate the advantages and reliability of screening for antinuclear antibodies (ANA) by enzyme immunoassay (ELISA).

METHODOLOGY

Sera from 96 patients comprising 51 with systemic lupus erythematosus (SLE), 11 with other systemic rheumatological diseases (SRD) and 34 with various other diseases (non-SRD) were tested using a commercial ELISA kit (ANA-Ease, Genesis Biotechnology, U.K.). These sera consisted of 53 immunofluorescence assay (IF) ANA-positive and 43 IF ANA-negative samples

RESULTS

We observed that when compared to the IF for ANA the sensitivity, specificity, predictive values for positives (PPV) and negatives (NPV) of ELISA were 90.7%, 85.7%, 89.1% and 87.8% respectively. Exclusion of borderline ELISA positive by slightly raising the cut-off optical density (OD) increased the specificity and PPV to 93.1%, and 94.1% respectively. Importantly, none of the non-SRD sera were positive when this higher cut-off was used. ELISA was noted to be strongly positive in three IF ANA-negative SLE patients. However there was no correlation between the ELISA ANA semi-quantitative index and the IF ANA titers.

CONCLUSIONS

ELISA appears to be suitable as a preliminary screening test for ANA. An appropriate cut-off should be identified to segregate low positive samples that could be false-positives. Nevertheless, IF will need to be performed to estimate the titers, identify patterns of ANA positive samples and confirm results of low positive "gray-zone" samples and ELISA negative sera from patients with a high index of clinical suspicion of SLE.

Dopamine D1 receptors mediate CREB phosphorylation via phosphorylation of the NMDA receptor at Ser897-NR1

Addictive drugs such as amphetamine and cocaine stimulate the dopaminergic system, activate dopamine receptors and induce gene expression throughout the striatum. The signal transduction pathway leading from dopamine receptor stimulation at the synapse to gene expression in the nucleus has not been fully elucidated. Here, we present evidence that D1 receptor stimulation leads to phosphorylation of the transcription factor Ca2+ and cyclic AMP response element binding protein (CREB) in the nucleus by means of NMDA receptor-mediated Ca2+ signaling. Stimulation of D1 receptors induces the phosphorylation of Ser897 on the NR1 subunit by protein kinase A (PKA). This phosphorylation event is crucial for D1 receptor-mediated CREB phosphorylation. Dopamine cannot induce CRE-mediated gene expression in neurons transfected with a phosphorylation-deficient NR1 construct. Moreover, stimulation of D1 receptors or increase in cyclic AMP levels leads to an increase in cytosolic Ca2+ in the presence of glutamate, but not in the absence of glutamate, indicating the ability of dopamine and cyclic AMP to facilitate NMDA channel activity. The recruitment of the NMDA receptor signal transduction pathway by D1 receptors may provide a general mechanism for gene regulation that is fundamental for mechanisms of drug addiction and long-term memory.

Transient low levels of antibodies at initial presentation of primary anti-phospholipid syndrome

We present, herein, a case of venous thrombosis who was lupus anticoagulant negative and had low levels of anticardiolipin antibodies at the time of initial presentation. A definite diagnosis of antiphospholipid syndrome (APS) could be made only when repeat testing, six months later, revealed a dramatic rise of these antibodies.

Potassium chloride depolarization mediates CREB phosphorylation in striatal neurons in an NMDA receptor-dependent manner

Potassium chloride (KCl)-depolarization has been used to study the properties of L-type Ca2+ channel-mediated signal transduction in hippocampal neurons. Calcium influx through L-type Ca2+ channels stimulates a second messenger pathway that transactivates genes under the regulatory control of the Ca2+-and cyclic AMP-responsive element (CRE). Here, we show that in striatal neurons, but not in hippocampal neurons, CRE binding protein (CREB) phosphorylation and CRE-mediated gene expression after KCl-depolarization depends on functional NMDA receptors. This difference in NMDA receptor dependence is not due to different properties of L-type Ca2+ channels in either neuronal type, but rather to different neuron-intrinsic properties. Despite this variation, the second messenger pathway activated by KCl requires Ca2+/calmodulin (CaM) kinase for CREB phosphorylation in both neuronal types. We conclude that depolarization by KCl works differently in striatal and hippocampal neurons.

A novel approach in treating recurrent bilateral hepaticojejunostomy biliary strictures post-liver transplantation: Successful use of Simpson's atherectomy device

Biliary complications occur in 6% to 34% of patients who undergo orthotopic liver transplantation. Strictures at the anastomosis site or elsewhere in the biliary tract are common. These strictures are amenable to interventional radiological and surgical procedures; however, retransplantation is sometimes an inevitable outcome. An 8-year-old boy received combined liver and kidney transplants May 31, 1998. Hepatic artery thrombosis was diagnosed postoperative day 1 and treated with revascularization. The choledochojejunostomy was revised twice and resulted in a high hepaticojejunostomy. Significant strictures on both the right and left hepatic ducts at the anastomosis site were unsuccessfully treated by multiple interventional radiological procedures. The option of retransplantation was seriously explored. Simpson's atherectomy device was used in a novel approach February 24, 1999, and strictures on both ducts were successfully treated. At 1-year postprocedure, the patient has normal liver function with no evidence of recurrence of the strictures. Further experience with this novel technique is required to assess its role in treating biliary strictures post liver transplantation.

Intracellular modulation of NMDA receptor function by antipsychotic drugs

The present study deals with the functional interaction of antipsychotic drugs and NMDA receptors. We show that both the conventional antipsychotic drug haloperidol and the atypical antipsychotic drug clozapine mediate gene expression via intracellular regulation of NMDA receptors, albeit to different extents. Data obtained in primary striatal culture demonstrate that the intraneuronal signal transduction pathway activated by haloperidol, the cAMP pathway, leads to phosphorylation of the NR1 subtype of the NMDA receptor at (897)Ser. Haloperidol treatment is likewise shown to increase (897)Ser-NR1 phosphorylation in rats in vivo. Mutation of (896)Ser and (897)Ser to alanine, which prevents phosphorylation at both sites, inhibits cAMP-mediated gene expression. We conclude that antipsychotic drugs have the ability to modulate NMDA receptor function by an intraneuronal signal transduction mechanism. This facilitation of NMDA activity is necessary for antipsychotic drug-mediated gene expression and may contribute to the therapeutic benefits as well as side effects of antipsychotic drug treatment.

L-Type Ca(2+) channels are essential for glutamate-mediated CREB phosphorylation and c-fos gene expression in striatal neurons

The second messenger pathways linking receptor activation at the membrane to changes in the nucleus are just beginning to be unraveled in neurons. The work presented here attempts to identify in striatal neurons the pathways that mediate cAMP response element-binding protein (CREB) phosphorylation and gene expression in response to NMDA receptor activation. We investigated the phosphorylation of the transcription factor CREB, the expression of the immediate early gene c-fos, and the induction of a transfected reporter gene under the transcriptional control of CREB after stimulation of ionotropic glutamate receptors. We found that neither AMPA/kainate receptors nor NMDA receptors were able to stimulate independently a second messenger pathway that led to CREB phosphorylation or c-fos gene expression. Instead, we saw a consecutive pathway from AMPA/kainate receptors to NMDA receptors and from NMDA receptors to L-type Ca(2+) channels. AMPA/kainate receptors were involved in relieving the Mg(2+) block of NMDA receptors, and NMDA receptors triggered the opening of L-type Ca(2+) channels. The second messenger pathway that activates CREB phosphorylation and c-fos gene expression is likely activated by Ca(2+) entry through L-type Ca(2+) channels. We conclude that in primary striatal neurons glutamate-mediated signal transduction is dependent on functional L-type Ca(2+) channels.