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Biomedical subjects

Animesh A Sinha

Publications and source records attributed to Animesh A Sinha.

At least 19 recordsLinked to original sources
PubMed2006

Preliminary data on Pemphigus vulgaris treatment by a proteomics-defined peptide: a case report.

BACKGROUND: Although described by Hippocrates in 400 B.C., pemphigus disease still needs a safe therapeutical approach, given that the currently used therapies (i.e. corticosteroids and immunosuppressive drugs) often provoke collateral effects. Here we present preliminary data on the possible use of a proteomics derived desmoglein peptide which appears promising in halting disease progression without adverse effects. METHODS: The low-similarity Dsg349-60REWVKFAKPCRE peptide was topically applied for 1 wk onto a lesion in a patient with a late-stage Pemphigus vulgaris (PV) complicated by diabetes and cataract disease. The peptide was applied as an adjuvant in combination with the standard corticosteroid-based immunosuppressive treatment. RESULTS: After 1 wk, the treated PV eroded lesion appeared dimensionally reduced and with an increased rate of re-epithelization when compared to adjacent non-treated lesions. Short-term benefits were: decrease of anti-Dsg antibody titer and reduction of the corticosteroid dosage. Long-term benefits: after two years following the unique 1-wk topical treatment, the decrease of anti-Dsg antibody titer persists. The patient is still at the low cortisone dosage. Adverse effects: no adverse effect could be monitored. CONCLUSION: With the limits inherent to any preliminary study, this case report indicates that topical treatment with Dsg349-60REWVKFAKPCRE peptide may represent a feasible first step in the search for a simple, effective and safe treatment of PV.

Journal Article↗
PubMed2006

Proteomic definition of a desmoglein linear determinant common to Pemphigus vulgaris and Pemphigus foliaceous.

BACKGROUND: A number of autoimmune diseases have been clinically and pathologically characterized. In contrast, target antigens have been identified only in a few cases and, in these few cases, the knowledge of the exact epitopic antigenic sequence is still lacking. Thus the major objective of current work in the autoimmunity field is the identification of the epitopic sequences that are related to autoimmune reactions. Our labs propose that autoantigen peptide epitopes able to evoke humoral (auto)immune response are defined by the sequence similarity to the host proteome. The underlying scientific rationale is that antigen peptides acquire immunoreactivity in the context of their proteomic similarity level. Sequences uniquely owned by a protein will have high potential to evoke an immune reaction, whereas motifs with high proteomic redundancy should be immunogenically silenced by the tolerance phenomenon. The relationship between sequence redundancy and peptide immunoreactivity has been successfully validated in a number of experimental models. Here the hypothesis has been applied to pemphigus diseases and the corresponding desmoglein autoantigens. METHODS: Desmoglein 3 sequence similarity analysis to the human proteome followed by dot-blot/NMR immunoassays were carried out to identify and validate possible epitopic sequences. RESULTS: Computational analysis led to identifying a linear immunodominant desmoglein-3 epitope highly reactive with the sera from Pemphigus vulgaris as well as Pemphigus foliaceous. The epitopic peptide corresponded to the amino acid REWVKFAKPCRE sequence, was located in the extreme N-terminal region (residues 49 to 60), and had low redundancy to the human proteome. Sequence alignment showed that human desmoglein 1 and 3 share the REW-KFAK-RE sequence as a common motif with 75% residue identity. CONCLUSION: This study 1) validates sequence redundancy to autoproteome as a main factor in shaping desmoglein peptide immunogenicity; 2) offers a molecular mechanicistic basis in analyzing the commonality of autoimmune responses exhibited by the two forms of pemphigus; 3) indicates possible peptide-immunotherapeutical approaches for pemphigus diseases.

Journal Article↗
PubMed2006

Modeling the bound conformation of Pemphigus vulgaris-associated peptides to MHC Class II DR and DQ alleles.

BACKGROUND: Pemphigus vulgaris (PV) is a severe autoimmune blistering disorder characterized by the presence of pathogenic autoantibodies directed against desmoglein-3 (Dsg3), involving specific DR4 and DR6 alleles in Caucasians and DQ5 allele in Asians. The development of sequence-based predictive algorithms to identify potential Dsg3 epitopes has encountered limited success due to the paucity of PV-associated allele-specific peptides as training data. RESULTS: In this work we constructed atomic models of ten PV associated, non-associated and protective alleles. Nine previously identified stimulatory Dsg3 peptides, Dsg3 96-112, Dsg3 191-205, Dsg3 206-220, Dsg3 252-266, Dsg3 342-356, Dsg3 380-394, Dsg3 763-777, Dsg3 810-824 and Dsg3 963-977, were docked into the binding groove of each model to analyze the structural aspects of allele-specific binding. CONCLUSION: Our docking simulations are entirely consistent with functional data obtained from in vitro competitive binding assays and T cell proliferation studies in DR4 and DR6 PV patients. Our findings ascertain that DRB1*0402 plays a crucial role in the selection of specific self-peptides in DR4 PV. DRB1*0402 and DQB1*0503 do not necessarily share the same core residues, indicating that both alleles may have different binding specificities. In addition, our results lend credence to the hypothesis that the alleles DQB1*0201 and *0202 play a protective role by binding Dsg3 peptides with greater affinity than the susceptible alleles, allowing for efficient deletion of autoreactive T cells.

Journal Article↗
PubMed2006

Cutaneous lupus erythematosus: understanding of clinical features, genetic basis, and pathobiology of disease guides therapeutic strategies.

Cutaneous features of the protean disease lupus erythematous (LE) constitute 4 of 11 diagnostic criteria for systemic lupus erythematosus (SLE) and are exhibited by approximately 3/4 of patients during the course of their disease. Because the pathogenesis of LE is multifactorial and polygenic, many of the details of the pathogenesis remain unclear. We review here the clinical features of cutaneous lupus and recent genetic data that elucidate potential candidate genes for both cutaneous lupus erythematosus (CLE) and SLE. We discuss advances in elucidating the autoimmune pathogenesis of CLE and SLE. Furthermore, promising experimental therapies based on these advances are reviewed in the context of B cell directed therapies, T cell directed therapies, disruption of B and T cell interactions, cytokine directed therapies and finally, end-effector targeted therapies.

Autoimmunity↗
PubMed2006

Genome-wide transcriptional profiling in human squamous cell carcinoma of the skin identifies unique tumor-associated signatures.

The elucidation of specific genetic changes associated with human cancer pathogenesis has focused efforts to relate such changes to the neoplastic phenotype. To further our understanding of the genetic basis of human squamous cell carcinoma (SCC) of the skin, this study used a genome-wide (12 627 sequences) approach to determine transcriptional signatures in lesional and nonlesional sites from five SCC patients. Several novel genes involving the p53 pathway, anti-apoptotic pathways, signal transduction, structural loss and DNA replication, including BCL2A1, MUC4, PTPN11 (SHP2) and FGF9, are upregulated in SCC and could warrant further study regarding their role in disease pathogenesis. SCC pathology is likely combinatorial in nature involving the compounded changes from several cellular processes.

Aged↗
PubMed2005

Disease relevant HLA class II alleles isolated by genotypic, haplotypic, and sequence analysis in North American Caucasians with pemphigus vulgaris.

Early studies of genetic susceptibility to pemphigus vulgaris (PV) showed associations between human leukocyte antigen (HLA) DR4 and DR6 and disease. The emergence of DNA sequencing techniques has implicated numerous DRB1 and DQB1 loci in various populations, leading to confusion regarding which exact alleles confer susceptibility. The strong linkage disequilibrium among DR and DQ HLA alleles further complicates the investigation of the true susceptibility loci. In this study, we report genotyping data for the largest sampling of North American Caucasian non-Jewish and Ashkenazi Jewish PV patients studied to date and compare our data with other population studies. To pinpoint true susceptibility, alleles among overrepresented sequences, we applied a step-wise reductionist analysis through (1) determination of the degree of linkage disequilibrium (LD) between purportedly associated alleles, (2) haplotype frequencies comparisons, and (3) primary sequence comparisons of disease-associated versus non-disease-associated alleles to identify crucial differences in amino acid residues in putative peptide binding pockets. Collectively, our data provide extended support for the hypothesis that the HLA associations in Caucasian PV patients map to DRB1*0402 and DQB1*0503 alone. Further structure-function studies will be required to define the exact mechanisms of HLA-mediated control of susceptibility and resistance to disease.

Adult↗
PubMed2005

The role of T cells in cutaneous autoimmune disease.

T cells assume a fundamental function in immunosurveillance and maintenance of the cutaneous immune barrier, yet derangement of their requisite role effects a range of cutaneous autoimmune diseases with significant associated morbidity. While blistering skin diseases, such as pemphigus vulgaris (PV), pemphigus foliaceus (PF) and bullous pemphigoid (BP) are mediated by antibodies directed against autoantigens found in the skin, recent evidence has shown that T cell activation is crucial for the initiation and coordination of this humoral response. Non-blistering skin diseases, such as alopecia areata (AA), vitiligo (VL) and psoriasis (PS) are increasingly believed to be directly mediated by the activities of autoreactive T cells. Here, we examine T lymphocyte control of antibody-mediated and cell-mediated processes involved in the pathoimmunology of the above mentioned skin diseases.

Autoantibodies↗
PubMed2005

T cell targeted immunotherapy for autoimmune disease.

Much emphasis has been placed on the so-called "biologics" in the treatment of immune disorders within the last few years. Here we discuss the expanding horizon of potential strategies for immunotherapies targeting T lymphocytes as key effectors and regulators of autoimmunity. We review emerging reagents in a variety of animal models and human disorders that may offer new therapeutic options in current or modified iterations.

Animals↗
PubMed2005

Characterization of polyclonal antibodies raised against a linear peptide determinant of desmoglein-3.

Our labs are pursueing the goal of exactly defining the qualities of peptide antigenicity, immunogenicity and pathogenicity in order to develop safe specific immunotherapies by utilizing specific portions of disease-associated-proteins (DAPs). Using as a model the Pemphigus vulgaris antigen (PVA) desmoglein 3 (Dsg3), we have studied the murine humoral response against the Dsg3 amino acid 49-60 peptide sequence, previously characterized as sequence having low similarity to the mouse proteome. The results show that the low-similarity Dsg3(49-60)REWVKFAKPCRE peptide does not elicit pathogenic antibodies.

Animals↗
PubMed2005

Gene therapy in cancer: the missing point.

Over the last century cancer research has produced data leading to a composite picture where gene mutations and epigenetic phenomena strictly relate and overlap. This complexity has repercussions on the anti-cancer therapeutical strategies. The therapeutic pathway paved by the kochian one-cause/one disease principle fails in front of a multigenic multiphenomena disease like cancer. We still do not know what target(s) to hit/modify in order to prevent/stop the carcinogenic progression. On the light of cancer statistics 2005, we discuss the need of exactly defining the cancer targets in order to exploit the high potential of gene therapy.

Chromosome Aberrations↗
PubMed2004

Epitope definition by proteomic similarity analysis: identification of the linear determinant of the anti-Dsg3 MAb 5H10.

BACKGROUND: Walking along disease-associated protein sequences in the search for specific segments able to induce cellular immune response may direct clinical research towards effective peptide-based vaccines. To this aim, we are studying the targets of the immune response in autoimmune diseases by applying the principle of non-self-discrimination as a driving concept in the identification of the autoimmunogenic peptide sequences. METHODS: Computer-assisted proteomic analysis of the autoantigen protein sequence and dot-blot/NMR immunoassays are applied to the prediction and subsequent validation of the epitopic sequences. RESULTS: Using the experimental model Pemphigus vulgaris/desmoglein 3, we have identified the antigenic linear determinant recognized by MAb 5H10, a monoclonal antibody raised against the extracellular domain of human desmoglein-3. The computer-assisted search for the Dsg3 epitope was conducted by analyzing the similarity level to the mouse proteome of the human desmoglein protein sequence. Dot-blot immunoassay analyses mapped the epitope within the sequence Dsg349-60 REWVKFAKPCRE, which shows low similarity to the mouse proteome. NMR spectroscopy analyses confirmed the specificity of MAb 5H10 for the predicted epitope. CONCLUSIONS: This report promotes the concept that low level of sequence similarity to the host's proteome may modulate peptide epitopicity.

Journal Article↗
PubMed2004

NMR probing of in silico identification of anti-HPV16 E7 mAb linear peptide epitope.

A proteomics-based approach was exploited in order to individuate peptide sequences having the immunogenic potential to evoke humoral response. The epitope search utilized two parameters: the similarity level of the peptide sequence to the host's proteins, and the peptide capability to bind to the major histocompatibility complex class II molecules. By this approach, the human papillomavirus 16 E7(49-63) RAHYNIVTFCCKCDS peptide was individuated as the immunogenic epitope recognized by an anti-HPV16 E7 monoclonal antibody raised against the full-length viral oncoprotein. In this report, two-dimensional nuclear magnetic resonance spectroscopic experiments unequivocally probe the HPV16 E7 epitope individuation.

Amino Acid Sequence↗
PubMed2003

Role of MHC II affinity and molecular mimicry in defining anti-HER-2/neu MAb-3 linear peptide epitope.

With the aid of computational biology, we have studied the possibility of predicting the peptides able to evoke humoral immune response by using as experimental model the human HER-2/neu breast cancer-associated antigen. We already demonstrated that HER-2/neu peptides, that are the target of humoral human and mouse immune responses, correspond to those sequences having a low degree of sequence similarity to host's proteome. Here we report that the linear peptide determinant of the anti-HER-2/neu MAb-3 is characterized by a low degree of sequence similarity to mouse proteome in combination with high binding potential to specific MHC II molecule.

Amino Acid Sequence↗
PubMed2003

Case and discussion of Lyme disease.

Lyme disease is a multisystem disease with prominent neurological involvement, primarily affecting the nervous system, skin, joints, and heart. We report the case of a patent with Lyme Disease and discuss the background as treatment of this condition.

Adult↗
PubMed2003

Using rituximab (anti-CD20 antibody) in a patient with paraneoplastic pemphigus.

Paraneoplastic pemphaigus (PNP) is a rare autoimmune mucocutaneous blistering disease that is commonly associated with underlying B-cell neoplasms. There is no standard therapy for PNP. Potent immunosuppression has been the only potentially effective treatment in the setting of malignancy because there is no correlation between tumor burden and activity of disease. Two recent case reports have noted the resolution of lesions of PNP after treatment of the underlying CD20+ B-cell lymphomas with rituximab. Rituximab is an anti-CD20 antibody that has had some success in treating proliferative B-cell disorders. We report a case of PNP in the setting of B-cell lymphoma that did not respond to this novel therapy, and discuss rituximab's putative mechanism of action along with the clinical settings in which this novel therapy may prove useful in the treatment of PNP.

Antibodies, Monoclonal↗
PubMed2002

Monoclonal and polyclonal humoral immune response to EC HER-2/NEU peptides with low similarity to the host's proteome.

We are studying peptide immunogenicity as a function of the similarity level to the host's proteome. By using as a model the breast/prostate cancer-associated HER-2/neu antigen, we analyzed the monoclonal and polyclonal humoral immune responses against HER-2/neu peptide motifs not shared with the host proteome. We show here that (i) a mouse monoclonal antibody (MAb) raised against the extracellular domain (EC) of human HER-2/neu oncoprotein recognized a linear peptide motif endowed with low similarity level to the mouse proteome; (ii) likewise, human sera from breast/prostate cancer patients preferentially recognized peptide fragments from the EC of the HER-2/neu oncoprotein having sequences that are not present in the human proteome. Together with previous results obtained in other disease models (cervical cancer-associated HPV16 E7 oncoprotein and Pemphigus vulgaris auto-antigen desmoglein-3), the present data suggest that a low level of sequence similarity to the host's proteome might be an important factor in shaping the pool of B cell epitopes.

Animals↗
PubMed2002

T cell receptor Beta chain gene usage in endemic pemphigus foliaceus (fogo selvagem).

The trimolecular complex comprised of the major histocompatibility complex, peptide antigen, and the T cell receptor is a requisite for T cell activation in normal and autoimmune responses. T cell receptor analysis is critical to further our understanding regarding mechanisms of T cell epitope selection and autoimmune initiation and progression and may help to identify targets for immunotherapy. Pemphigus foliaceus is an autoimmune blistering skin disease characterized by intraepidermal blisters and circulating autoantibodies directed against desmoglein 1, a 160 kDa transmembrane desmosomal molecule expressed in keratinocytes. As tissue damage is mediated by anti-desmoglein 1 antibodies, an initial T cell response is a likely requirement for autoantibody generation in this disease. To elucidate the role of pathogenic T cells in autoimmunity further, we have directly characterized the T cell receptor of T cells derived from pemphigus foliaceus patients. Complementary DNA was isolated from 17 desmoglein 1 specific T cell clones generated from pemphigus foliaceus patients by clonal expansion in vitro. To analyze the T cell repertoire, a panel of primers, collectively specific for the known human T cell receptor beta variable region (TCRBV) families were paired with a constant region primer to polymerase chain reaction to amplify one distinct T cell receptor beta variable region allele for each T cell clone studied. Polymerase chain reaction products were sequenced to determine exact beta chain gene usage. In the 17 clones tested, 10 distinct T cell receptor beta variable region usages and nine T cell receptor beta joining gene segment usages were identified. Furthermore, T cell receptor beta variable region and beta joining usage did not appear to be random, but oligoclonal in nature, with some preference shown for T cell receptor beta variable region 5S1 and T cell receptor BJ2S5.

Amino Acid Sequence↗