Apoptosis induced by FasL and TRAIL/Apo2L in the pathogenesis of thyroid diseases

Sirtuin 6 is a key contributor to gender differences in acute kidney injury

Acute kidney injury (AKI) is rapidly increasing nowadays and at a high risk to progress into chronic kidney disease (CKD). Of note, men are more susceptive to AKI, suggesting gender differences in AKI patients. However, the underlying mechanisms remain largely unclear. To test it, we adopted two experimental models of AKI, including ischemia/reperfusion injury and rhabdomyolysis, which were constructed in age-matched male and female mice. We found severe damages of tubular apoptosis, mitochondrial dysfunction, and loss of renal function showing in male mice, while female mice only had very mild injury. We further tested the expression of Sirtuins, and found that female mice could preserve more Sirtuin members' expression in case of kidney damage. Among Sirtuin family, Sirtuin 6 was maximally preserved in injured kidney in female mice, suggesting its important role involved in the gender differences of AKI pathogenesis. We then found that knockdown of androgen receptor (AR) attenuated tubular damage, mitochondrial dysfunction and retarded the loss of renal function. Overexpression of Sirtuin 6 also showed similar results. Furthermore, in cultured tubular cells, dihydrotestosterone (DHT) decreased Sirtuin 6 expression and exacerbated cell apoptosis. Ectopic expression of Sirtuin 6 sufficiently inhibited DHT-induced cell apoptosis. Mechanically, we found AR inhibited Sirtuin 6, leading to the repression of binding of Sirtuin 6 with PGC-1α. This resulted in acetylation of PGC-1α and inhibition of its activity, further triggered the loss of mitochondrial homeostasis. Our results provided new insights to the underlying mechanisms of gender differences in AKI, suggesting Sirtuin 6 maybe a new therapeutic target for preventing AKI in male patients.

Emerging therapeutic role of Prunella vulgaris in thyroid disease

Thyroid disease is characterized by unusual levels of thyroid hormones, which results in either hyperthyroidism or hypothyroidism. The pathology of a particular type or stage of thyroid disease is very complicated, and always linked to a variety of biological functions. Although the mortality rate is not high, thyroid dysfunction could lead to metabolic and immunological disorders that can subsequently cause discomfort. To date, many drugs are suggested to have curative effects on thyroid disease, however, drug toxicity and long treatment periods encourage the search for more promising ones. Prunella vulgaris L. (Labiatae) is a popular herb that has shown great potential for improving human immunity and organ protection. It has been extensively used in the treatment of many diseases but its ability to treat specific diseases has not been fully reported. In this review, a literature search regarding herbs and herbal recipes for treating thyroid disease were carried out, organized, and summarized. In addition, this study conducted a literature search on the current situation and progress of P. vulgaris treatment for various diseases. Finally, this study discussed studies regarding P. vulgaris treatment of goiter, and the mechanism of treatment through the regulation of apoptosis. Accordingly, a combination therapy of herbs and Western medicine can provide significant therapeutic effects in the clinical treatment of thyroid disease. Furthermore, the association between P. vulgaris and various diseases suggests that P. vulgaris is rich in a variety of active substances that can fight oxidation and participate in the regulation of apoptosis, thus having a protective effect on the thyroid. Here, a comprehensive literature review regarding the application of herbs or herbal recipes in the treatment of thyroid disease was presented. It is concluded that there is strong evidence for further research regarding the use of P. vulgaris in the treatment of thyroid diseases.

Receptor Specificity Engineering of TNF Superfamily Ligands

The tumor necrosis factor (TNF) ligand family has nine ligands that show promiscuity in binding multiple receptors. As different receptors transduce into diverse pathways, the study on the functional role of natural ligands is very complex. In this review, we discuss the TNF ligands engineering for receptor specificity and summarize the performance of the ligand variants in vivo and in vitro. Those variants have an increased binding affinity to specific receptors to enhance the cell signal conduction and have reduced side effects due to a lowered binding to untargeted receptors. Refining receptor specificity is a promising research strategy for improving the application of multi-receptor ligands. Further, the settled variants also provide experimental guidance for engineering receptor specificity on other proteins with multiple receptors.

Association of Pro-apoptotic Bad Gene Expression Changes with Benign Thyroid Nodules

BACKGROUND/AIM

This study aimed to investigate the role of the mitochondrial apoptotic pathway in benign thyroid nodules.

MATERIALS AND METHODS

Paired samples of nodular and normal tissues were collected from 26 patients with nodular goiters undergoing thyroidectomy. Variable expression of Bcl-2, Bax and Bad genes were evaluated by quantitative PCR.

RESULTS

Expression level of Bad gene in nodules was found to be significantly decreased compared to normal tissues (p=0.049). A positive correlation was observed between nodule size and Bad expression levels (correlation coefficient=0.563, p=0.004); and this correlation was stronger in hot nodules (n=18, correlation coefficient=0.689, p=0.003). No significant difference was observed between nodular and normal tissue expressions of Bax and Bcl-2.

CONCLUSION

These results suggest that Bad expression correlates with the size of benign thyroid nodules and also its relatively lower expression in nodules, warrant further investigation.

Diagnostic significance of serum concentrations of soluble Fas ligand (sFasL) in children with autoimmune thyroid disease

INTRODUCTION

The aim of the study was to assess serum levels of sFasL as a marker of thyroid dysfunction in children with autoimmune thyroid disease (AITD).

DESIGN

The group comprised 45 newly diagnosed children with Hashimoto's thyroiditis and Graves' disease versus euthyroid control group: 11 with hypothyroidism (10 girls and 1 boy, aged 12.2 ± 1.9 years), 19 children with hyperthyroidism (15 girls and 4 boys, aged 12.4 ± 4.9 years) and 15 healthy subjects (7 girls and 8 boys, aged 10.5 ± 4.8 years).

METHODS

Thyroid function (TSH, fT4, fT3), autoimmune (ATG, ATPO, TRAb) and anthropometric (weight, height, BMI, BMI-SDS, Cole index) parameters were evaluated. sFasL concentration was measured by ELISA. Nonparametric statistical test and ROC analysis were performed to assess the data.

RESULTS

We found no significant differences in serum concentrations of sFasL between boys and girls in the studied groups. Significantly higher sFasL levels (median 0.26 ng/ml) were identified in children with hypothyroidism compared with the control group (median 0.06 ng/ml, p < 0.001) and in comparison to a group of children with hyperthyroidism (median 0.14 ng/ml, p < 0.05). ROC analysis indicates that sFasL effectively discriminated hypothyroid and healthy children (area under the curve/AUC = 0.897; p < 0,001; sensitivity: 100%, specificity: 73.3%), as well as both clinically opposing states: hyperthyroidism and hypothyroidism among themselves (AUC = 0.833; p= 0,003; sensitivity: 94,7%, specificity: 72.7%).

CONCLUSIONS

Our work shows that sFasL may be useful marker in the assessment of thyroid dysfunction in children with autoimmune thyroid disease.

A polymorphism in the promoter region of the selenoprotein S gene (SEPS1) contributes to Hashimoto's thyroiditis susceptibility

CONTEXT

The association between selenium and inflammation and the relevance of selenoproteins in follicular thyroid cell physiology have pointed to a putative role of selenoproteins in the pathogenesis of autoimmune thyroid diseases.

OBJECTIVE

The aim of this study was to evaluate the role of a promoter variation in SEPS1, the selenoprotein S gene, in the risk for developing Hashimoto's thyroiditis (HT).

DESIGN

A case-control study was performed to assess the association of genetic variation in the SEPS1 gene (SEPS1 -105G/A single-nucleotide polymorphism, rs28665122) and HT.

SETTING

The study was conducted in north Portugal, Porto, in the period of 2007-2013.

PATIENTS OR OTHER PARTICIPANTS

A total of 997 individuals comprising 481 HT patients and 516 unrelated controls were enrolled in the study.

MAIN OUTCOME MEASURES

Genetic variants were discriminated by real-time PCR using TaqMan single-nucleotide polymorphism genotyping assays.

RESULTS

There is a significant association between the SEPS1 -105 GA and AA genotypes and HT [odds ratio (OR) 2.24, confidence interval (CI) 1.67-3.02, P < 5.0 × 10(-7), and OR 2.08, CI 1.09-3.97, P = .0268, respectively]. The A allele carriers are in higher proportion in the patient group than in the control population (46.2% vs 28.1%, P < 5.0 × 10(-7)) with an OR (CI) of 2.22 (1.67-2.97). The proportion of patients carrying the A allele is significantly higher in male patients with HT, representing a 3.94 times increased risk (P = 7.9 × 10(-3)).

CONCLUSION

Our findings support the existence of a link between SEPS1 promoter genetic variation and HT risk.

FOLFIRI plus dulanermin (rhApo2L/TRAIL) in a patient with BRAF-mutant metastatic colon cancer

Colorectal cancer patients with BRAF-mutant tumors have a more aggressive, rapidly progressing disease that is in critical need of novel therapeutic approaches. Indeed, whereas the median overall survival (OS) of colorectal cancer (CRC) patients receiving standard-of-care therapy is approximately two years or more if their tumors express wild-type BRAF and wild-type KRAS, median OS is less than twelve months with tumors expressing V600E-mutant BRAF and wild-type KRAS. Pro-apoptotic receptor agonists are a class of biologic agents under development to induce tumor-specific apoptosis and are being combined with classical chemotherapy or targeted agents in clinical trials. Herein, we present the case of a patient with bulky V600E-mutant BRAF hepatic flexure colon carcinoma, treated initially with FOLFOX plus bevacizumab neoadjuvant therapy and surgery. The patient had a rapid tumor relapse with metastatic disease to the liver and lung, and was enrolled in a phase 1b open-label clinical study, where he received the FOLFIRI regimen in combination with the pro-apoptotic receptor agonist dulanermin (rhApo2L/TRAIL). The patient maintained stable disease through 25 doses administered every two weeks before his disease progressed. After coming off study, the patient underwent surgical debulking and received intraperitoneal hyperthermic chemotherapy. He subsequently relapsed and was treated with FOLFIRI plus cetuximab. At the time of this report, the patient remains on active treatment. It is unclear what effect dulanermin may have had on the course of his disease, but it is noteworthy that the patient remained on FOLFIRI plus dulanermin therapy for a period that exceeded the median OS for patients with advanced, aggressive BRAF-mutant CRC. It is also noteworthy that at the time of this report the patient's overall survival since diagnosis has exceeded 30 months, which is beyond what is generally observed even for patients with CRC harboring wild-type BRAF and wild-type KRAS.

Hashimoto's Thyroiditis: From Genes to the Disease

Hashimoto's thyroiditis (HT) is the most prevalent autoimmune thyroid disorder. Intrathyroidal lymphocytic infiltration is followed by a gradual destruction of the thyroid gland which may lead to subclinical or overt hypothyroidism. Biochemical markers of the disease are thyroid peroxidase and/or thyroglobulin autoantibodies in the serum which are present with a higher prevalence in females than in males and increase with age. Although exact mechanisms of aetiology and pathogenesis of the disorder are not completely understood, a strong genetic susceptibility to the disease has been confirmed predominantly by family and twin studies. Several genes were shown to be associated with the disease occurrence, progression, and severity. Genes for human leukocyte antigen, cytotoxic T lymphocyte antigen-4, protein tyrosine phosphatase nonreceptor-type 22, thyroglobulin, vitamin D receptor, and cytokines are considered to be of utmost importance. Amongst endogenous factors for the disease development, the attention is focused predominantly on female sex, pregnancy with postpartum period and fetal microchimerism. Environmental factors influencing HT development are iodine intake, drugs, infections and different chemicals. Disturbed self-tolerance accompanied by the increased antigen presentation is a prerequisite for the HT occurrence, whereas proper interaction of thyroid cells, antigen presenting cells, and T cells are necessary for the initiation of thyroid autoimmunity. Secreted cytokines lead predominantly to T-helper type 1 (Th1) response as well as to Th 17 response which has only recently been implicated. Final outcome of HT is thyroid destruction which is mostly a consequence of the apoptotic processes combined with T-cell mediated cytotoxicity.

Guidelines of the French society of endocrinology for the management of thyroid nodules

The present document is a follow-up of the clinical practice guidelines of the French Society of Endocrinology, which were established for the use of its members and made available to scientific communities and physicians. Based on a critical analysis of data from the literature, consensuses and guidelines that have already been published internationally, it constitutes an update of the report on the diagnostic management of thyroid nodules that was proposed in France, in 1995, under the auspices of the French National Agency for Medical Evaluation (l'Agence nationale d'évaluation médicale). The current guidelines were deliberated beforehand by a number of physicians that are recognised for their expertise on the subject, coming from the specialities of endocrinology (the French Thyroid Research Group) and surgery (the French Association for Endocrine Surgery), as well as representatives from the fields of biology, ultrasonography, cytology and nuclear medicine. The guidelines were presented and submitted for the opinion of the members of the Society at its annual conference, which was held in Nice from 7-10 October 2009. The amended document was posted on the website of the Society and benefited from additional remarks of its members. The final version that is presented here was not subjected to methodological validation. It does not claim to be universal in its scope and will need to be revised in concert with progress made in technical and developmental concepts. It constitutes a document that the Society deems useful for distribution concerning the management of thyroid nodules, which is current, efficient and cost effective.

Effect of transgenic overexpression of FLIP on lymphocytes on development and resolution of experimental autoimmune thyroiditis

In our previous studies, resolution of granulomatous experimental autoimmune thyroiditis (G-EAT) was promoted when thyroid epithelial cells were protected from Fas-mediated apoptosis due to transgenic overexpression of FLIP. We hypothesized that if FLIP were overexpressed on lymphocytes, CD4(+) effector cells would be protected from Fas-mediated apoptosis, and resolution would be delayed. To test this hypothesis, we generated transgenic (Tg) mice overexpressing FLIP under the CD2 promoter. Transgenic FLIP was expressed on CD4(+) and CD8(+) T cells and B cells. Transgenic overexpression of FLIP protected cultured splenocytes from Fas-mediated, but not irradiation-induced, apoptosis in vitro. Unexpectedly, Tg(+) donor cells transferred minimal G-EAT, which was partially overcome by depleting donor CD8(+) T cells. When Tg(+) and Tg(-) donors transferred equivalent disease, G-EAT resolution was delayed in FLIP transgenic mice. However, CD2-FLIP Tg(+) donors often transferred less severe G-EAT, even after depletion of CD8(+) T cells. This influenced the rate of G-EAT resolution, resulting in little difference in G-EAT resolution between groups. Tg(+) mice always had reduced anti-mouse thyroglobulin autoantibody responses, compared with Tg(-) littermates, presumably because of FLIP overexpression on B cells. These results suggest that effects of transgenic FLIP on a particular autoimmune disease vary, depending on what cells express the transgene and whether those cells are effector cells or if they function to modulate disease.

Regulation of major histocompatibility complex gene expression in thyroid epithelial cells by methimazole and phenylmethimazole

Increased expression of major histocompatibility complex (MHC) class-I genes and aberrant expression of MHC class-II genes in thyroid epithelial cells (TECs) are associated with autoimmune thyroid diseases. Previous studies have shown that methimazole (MMI) reduces MHC class-I expression and inhibits interferon-gamma (IFN-gamma or IFNG as listed in the MGI Database)-induced expression of the MHC class-II genes in TECs. The action of MMI on the MHC class-I genes is transcriptional, but its mechanism has not been investigated previously. In the present study, we show that in Fisher rat thyroid cell line 5 cells, the ability of MMI and its novel derivative phenylmethimazole (C10) to decrease MHC class-I promoter activity is similar to TSH/cAMP suppression of MHC class-I and TSH receptor genes, and involves a 39 bp silencer containing a cAMP response element (CRE)-like site. Furthermore, we show that C10 decreases MHC class-I gene expression to a greater extent than MMI and at 10- to 50-fold lower concentrations. C10 also reduces the IFN-gamma-induced increase in the expression of MHC class-I and MHC class-II genes more effectively than MMI. Finally, we show that in comparison to MMI, C10 is a better inhibitor of specific protein-DNA complexes that are formed with a CRE-like element on the MHC class-II promoter. These data support the conclusion that the immunosuppressive mechanism by which MMI and C10 inhibit MHC gene expression mimics 'normal' hormonal suppression by TSH/cAMP.

Apoptotic study in Graves disease treated with thyroid arterial embolization

OBJECTIVE

To investigate apoptosis in the thyroid of Graves disease (GD) induced by thyroid arterial embolization.

MATERIALS AND METHODS

Forty one patients with clinically and laboratorily ascertained GD were treated with thyroid arterial embolization and followed up for 3-54 months following embolization. Prior to embolization and at 1, 3, 6, 12 and 36 months following embolization, thyroid autoimmunue antibodies were tested respectively, including thyroid stimulating antibody (TSAb), thyroglobulin antibody (TGAb) and thyroid microsomal antibody (TMAb). Thyroid biopsy was performed under the guidance of computed tomography for immunohistochemistry examination using semi-quantity analysis.

RESULTS

The positive staining of Fas and FasL was mostly in the cytoplasma and cell membrane, the positive expression of Bax was mainly in the cytoplasma, and no positive expression of P53 was detected in the thyroid cells before embolization. After arterial embolziation, the positive cell number and staining degree of these genes were both greater than before embolization.

CONCLUSION

The treatment method of thyroid arterial embolization can effectively enhance the positive expression of pro-apoptotic genes of Fas, FasL, Bax, Bcl-2 and P53 in GD thyroid, thus promoting apoptosis of GD thyroid and helping restore the thyroid size and function to normal conditions.

Cytokines, Graves' disease, and thyroid-associated ophthalmopathy

Graves' disease, an autoimmune process associated with thyroid dysfunction, can also manifest as remodeling of orbital connective tissue. Affected tissues exhibit immune responses that appear to be orchestrated by resident cells and those recruited from the bone marrow through their expression and release of cytokines and surface display of cytokine receptors. Cytokines are small molecules produced by many types of cells, including those of the "professional" immune system. Aberrant cytokine expression appears to play an important role in the pathogenesis of many human diseases, including thyroid autoimmunity. The skewed pattern of cytokine expression in the thyroid, including the T helper cell bias, may condition the response to apoptotic signals and determine the characteristics of an autoimmune reaction. Furthermore, chemoattractant cytokines, including IL16, RANTES, and CXCL10, elaborated by resident cells in the thyroid and orbit may provoke mononuclear cell infiltration. Other cytokines may drive cell activation and tissue remodeling. Thus cytokines and the signaling pathways they activate represent attractive therapeutic targets. Interruption of these might alter the natural course of Graves' disease and its orbital manifestations.

Long-term immunological study in Graves' disease treated with thyroid arterial embolization

OBJECTIVE

The aim of this study was to investigate long-term immunological changes after the treatment of Graves' disease (GD) with thyroid arterial embolization and the effect of thyroid arterial embolization on the body's immunological functions.

MATERIALS AND METHODS

Forty-one patients with clinically and laboratorily ascertained GD were treated with thyroid arterial embolization and followed up for 3-54 months following embolization. Prior to embolization and at 1, 3, 6, 12, and 36 months following embolization, thyroid autoimmune antibodies were tested respectively, including thyroid stimulating antibody (TSAb), thyrotropin antibody (TRAb), thyroglobulin antibody (TGAb), and thyroid microsomal antibody (TMAb), as well as subgroup lymphocytes of CD16+CD56+, CD19+, CD3+, CD3+CD4+ and CD3+CD8+. The autoimmune status of GD patients prior to embolization and the dynamic changes of the immunological function after embolization were analyzed.

RESULTS

The therapy of thyroid arterial embolization could effectively decrease the activity/titer and positive rate of TRAb and the ratio of CD4+/ CD8+ to normal levels at 6 months following embolization, while the ratio of CD3+CD8+ increased gradually to normal level at 1 year following embolization. In patients with recurrence, TSAb and TRAb remained at a higher level, while the rate of CD3+CD8+ and the ratio of CD4+/CD8+ were not statistically significantly different from those before embolization.

CONCLUSION

Immunological functional disorder exists in GD patients. The treatment method of thyroid arterial embolization can effectively resume the basic immunological function to normal range while patients with recurrence have no significant improvement, suggesting that thyroid arterial embolization has an effective role in adjusting the immunological function.

Differential expression of Fas system apoptotic molecules in peripheral lymphocytes from patients with Graves' disease and Hashimoto's thyroiditis

OBJECTIVE

To examine whether the Fas system apoptotic molecules are differentially expressed in Graves' disease (GD) and Hashimoto's thyroiditis (HT), the two opposite phenotypes of autoimmune thyroid disease (AITD).

DESIGN

The expression of Fas and Fas ligand (FasL) on peripheral CD4 and CD8 lymphocytes, and non-lymphoid immune cells as well as their soluble forms in serum from untreated patients with GD and HT were evaluated.

METHODS

Flow cytometry was performed for the study of peripheral immune cells from 70 newly diagnosed patients with AITD (55 with HT and 15 with GD) and 20 controls. ELISA was used for the measurement of soluble Fas (sFas) in serum samples from a subgroup of 35 AITD patients.

RESULTS

An increase in the proportion of CD4 and CD8 cells expressing Fas was found in both GD and HT, albeit with some differences, when compared with controls. Importantly, in GD patients, the intensity of Fas expression on CD4 and CD8 lymphocytes was reduced and sFas levels in serum were simultaneously increased when compared with HT patients and controls.

CONCLUSIONS

The Fas system apoptotic molecules appear to be differentially expressed on peripheral lymphocytes in the two opposite phenotypes of AITD.

Immune pathogenesis of Mixed Connective Tissue Disease: a short analytical review

Mixed Connective Tissue Disease (MCTD) was first described 35 years ago by Gordon C. Sharp and his colleagues. In the ensuing decades, a clearer understanding of the clinical and serologic features of MCTD has emerged. Classification criteria now exist to define MCTD for study purposes, the long-term outcome of the disease has been established, and novel genetic associations within the major histocompatibility complex on chromosome 6 and select regions on chromosome 3 have been identified. Studies on immune pathogenesis have made substantial progress in advancing our understanding of MCTD. In MCTD, there is a complex interaction of the innate and adaptive immune system that culminates in autoimmune disease. Antigenic structural modification occurring during apoptosis or other modifications of self antigens leads to an autoantigen driven immune process with innate immune activation, immunoglobulin G autoantibody production directed against select components of the spliceosome, B lymphocyte activation, and CD4 and CD8 T lymphocyte participation.

Expression of transgenic FLIP on thyroid epithelial cells inhibits induction and promotes resolution of granulomatous experimental autoimmune thyroiditis in CBA/J mice

Granulomatous experimental autoimmune thyroiditis (G-EAT) is induced by transfer of thyroglobulin-primed in vitro activated splenocytes. Thyroid lesions reach maximal severity 20 d later, and inflammation resolves or progresses to fibrosis by d 60, depending on the extent of thyroid damage at d 20. Depletion of CD8+ T cells inhibits G-EAT resolution. We showed that expression of Fas-associated death domain-like IL-1beta-converting enzyme inhibitory protein (FLIP) transgene (Tg) on thyroid epithelial cells (TECs) of DBA/1 mice had no effect on G-EAT induction but promoted earlier resolution of G-EAT. However, when CBA/J wild-type donor cells were transferred to transgenic CBA/J mice expressing FLIP on TECs, they developed less severe G-EAT than FLIP Tg- littermates. Both strains expressed similar levels of the FLIP Tg, but endogenous FLIP was up-regulated to a greater extent on infiltrating T cells during G-EAT development in DBA/1 compared with CBA/J mice. After transient depletion of CD8+ T cells, FLIP Tg+ and Tg- CBA/J recipients both developed severe G-EAT at d 20. Thyroid lesions in CD8-depleted Tg+ recipients were resolving by d 60, whereas lesions in Tg- littermates did not resolve, and most were fibrotic. FLIP Tg+ recipients had increased apoptosis of CD3+ T cells compared with Tg- recipients. The results indicate that transgenic FLIP expressed on TECs in CBA/J mice promotes G-EAT resolution, but induction of G-EAT is inhibited unless CD8+ T cells are transiently depleted.

Murine FLIP transgene expressed on thyroid epithelial cells promotes resolution of granulomatous experimental autoimmune thyroiditis in DBA/1 mice

Granulomatous experimental autoimmune thyroiditis (G-EAT) is induced by mouse thyroglobulin-sensitized splenocytes activated in vitro with mouse thyroglobulin and interleukin-12. In wild-type (WT) DBA/1 recipients of WT donor splenocytes, thyroid lesions reach maximal severity at day 20, with ongoing inflammation and extensive fibrosis at day 60. Our previous studies indicated the site of expression of FLIP and Fas ligand [thyroid epithelial cells (TECs) versus inflammatory cells] differed in mice when lesions would resolve or progress to fibrosis. To test the hypothesis that expression of FLIP by TECs would promote earlier G-EAT resolution in DBA/1 mice, transgenic (Tg) DBA/1 mice expressing FLIP on TECs were generated. In FLIP Tg(+) and Tg(-) littermate recipients of WT donor splenocytes, G-EAT severity was comparable at day 20, but fibrosis was decreased, and many lesions resolved by day 60 in Tg(+) but not Tg(-) recipients. FLIP and Fas ligand were primarily expressed by TECs in Tg(+) recipients and by inflammatory cells in Tg(-) recipients at day 60. Apoptosis of inflammatory cells was greater, and expression of proinflammatory cytokines was decreased in thyroids of Tg(+) compared with Tg(-) recipients. These results are consistent with the hypothesis that transgenic expression of FLIP on thyroid epithelial cells promotes earlier resolution of granulomatous experimental autoimmune thyroiditis.

Targeting BRAFV600E in thyroid carcinoma: therapeutic implications

B-Raf is an important mediator of cell proliferation and survival signals transduced via the Ras-Raf-MEK-ERK cascade. BRAF mutations have been detected in several tumors, including papillary thyroid carcinoma, but the precise role of B-Raf as a therapeutic target for thyroid carcinoma is still under investigation. We analyzed a panel of 93 specimens and 14 thyroid carcinoma cell lines for the presence of BRAF mutations and activation of the mitogen-activated protein/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. We also compared the effect of a B-Raf small inhibitory RNA construct and the B-Raf kinase inhibitor AAL881 on both B-Raf wild-type and mutant thyroid carcinoma cell lines. We found a high prevalence of the T1799A (V600E) mutation in papillary and anaplastic carcinoma specimens and cell lines. There was no difference in patient age, B-Raf expression, Ki67 immunostaining, or clinical stage at presentation between wild-type and BRAF(V600E) specimens. Immunodetection of phosphorylated and total forms of MEK and ERK revealed no difference in their phosphorylation between wild-type and BRAF(V600E) patient specimens or cell lines. Furthermore, a small inhibitory RNA construct targeting the expression of both wild-type B-Raf and B-Raf(V600E) induced a comparable reduction of viability in both wild-type and BRAF(V600E) mutant cancer cells. Interestingly, AAL881 inhibited MEK and ERK phosphorylation and induced apoptosis preferentially in BRAF(V600E)-harboring cells than wild-type ones, possibly because of better inhibitory activity against B-Raf(V600E). We conclude that B-Raf is important for the pathophysiology of thyroid carcinomas irrespective of mutational status. Small molecule inhibitors that selectively target B-Raf(V600E) may provide clinical benefit for patients with thyroid cancer.

Familial aggregation and linkage analysis of autoantibody traits in pedigrees multiplex for systemic lupus erythematosus

Autoantibodies are clinically relevant biomarkers for numerous autoimmune disorders. The genetic basis of autoantibody production in systemic lupus erythematosus (SLE) and other autoimmune diseases is poorly understood. In this study, we characterized autoantibody profiles in 1,506 individuals from 229 multiplex SLE pedigrees. There was strong familial aggregation of antinuclear antibodies (ANAs), anti-double-stranded DNA (dsDNA), anti-La/SSB, anti-Ro/SSA, anti-Sm, anti-nRNP (nuclear ribonucleoprotein), IgM antiphospholipid (aPL) antibodies (Abs) and rheumatoid factor (RF) across these families enriched for lupus. We performed genome-wide linkage analyses in an effort to map genes that contribute to the production of the following autoantibodies: Ro/SSA, La/SSB, nRNP, Sm, dsDNA, RF, nuclear and phospholipids. Using an approach to minimize false positives and adjust for multiple comparisons, evidence for linkage was found to anti-La/SSB Abs on chromosome 3q21 (adjusted P=1.9 x 10(-6)), to anti-nRNP and/or anti-Sm Abs on chromosome 3q27 (adjusted P=3.5 x 10(-6)), to anti-Ro/SSA and/or anti-La/SSB Abs on chromosome 4q34-q35 (adjusted P=3.4 x 10(-4)) and to anti-IgM aPL Abs on chromosome 13q14 (adjusted P=2.3 x 10(-4)). These results support the hypothesis that autoantibody production is a genetically complex trait. Identification of the causative alleles will advance our understanding of critical molecular mechanisms that underlie SLE and perhaps other autoimmune diseases.

Thyroid cancer and the immune system: a model for effective immune surveillance

Differentiated thyroid cancers, including papillary and follicular variants, are a useful model with which to examine interactions between cancer and the immune system. Differentiated thyroid cancers are detected in only 20,000 individuals annually in the USA, but thyroid microcarcinomas (< 1 cm in diameter) are far more common. This suggests that the immune system might restrain the growth of these microcarcinomas. On the clinical level, patients with lymphocytes that infiltrate into papillary thyroid cancer have improved survival, supporting the notion that immune system activation might improve this. Together, these observations suggest that the growth and distant spread of thyroid carcinoma are suppressed by mechanisms of immune surveillance, possibly involving lymphocytes, macrophages and their secreted products. In this review, we examine the general hypothesis of immune surveillance and the data pertaining to the roles of lymphocytes, dendritic cells and cytokines in the immune response against thyroid cancers.

Autocrine production of interleukin-4 and interleukin-10 is required for survival and growth of thyroid cancer cells

Although CD95 and its ligand are expressed in thyroid cancer, the tumor cell mass does not seem to be affected by such expression. We have recently shown that thyroid carcinomas produce interleukin (IL)-4 and IL-10, which promote resistance to chemotherapy through the up-regulation of Bcl-xL. Here, we show that freshly purified thyroid cancer cells were completely refractory to CD95-induced apoptosis despite the consistent expression of Fas-associated death domain and caspase-8. The analysis of potential molecules able to prevent caspase-8 activation in thyroid cancer cells revealed a remarkable up-regulation of cellular FLIP(L) (cFLIP(L)) and PED/PEA-15, two antiapoptotic proteins whose exogenous expression in normal thyrocytes inhibited the death-inducing signaling complex of CD95. Additionally, small interfering RNA FLIP and PED antisense sensitized thyroid cancer cells to CD95-mediated apoptosis. Exposure of normal thyrocytes to IL-4 and IL-10 potently up-regulated cFLIP and PED/PEA-15, suggesting that these cytokines are responsible for thyroid cancer cell resistance to CD95 stimulation. Moreover, treatment with neutralizing antibodies against IL-4 and IL-10 or exogenous expression of suppressor of cytokine signaling-1 of thyroid cancer cells resulted in cFLIP and PED/PEA-15 down-regulation and CD95 sensitization. More importantly, prolonged IL-4 and IL-10 neutralization induced cancer cell growth inhibition and apoptosis, which were prevented by blocking antibodies against CD95 ligand. Altogether, autocrine production of IL-4 and IL-10 neutralizes CD95-generated signals and allows survival and growth of thyroid cancer cells. Thus, IL-4 and IL-10 may represent key targets for the treatment of thyroid cancer.

Induction and Regulation of Fas-Mediated Apoptosis in Human Thyroid Epithelial Cells

Fas-mediated apoptosis has been proposed to play an important role in the pathogenesis of Hashimoto’s thyroiditis. Normal thyroid cells are resistant to Fas-mediated apoptosis in vitro but can be sensitized by the unique combination of interferon-γ and IL-1β cytokines. We sought to examine the mechanism of this sensitization and apoptosis signaling in primary human thyroid cells. Without the addition of cytokines, agonist anti-Fas antibody treatment of the thyroid cells resulted in the cleavage of proximal caspases, but this did not lead to the activation of caspase 7 and caspase 3. Apoptosis associated with the cleavage of caspases 7, 3, and Bid, and the activation of mitochondria in response to anti-Fas antibody occurred only after cytokine pretreatment. Cell surface expression of Fas, the cytoplasmic concentrations of procaspases 7, 8, and 10, and the proapoptotic molecule Bid were markedly enhanced by the presence of the cytokines. In contrast, P44/p42 MAPK (Erk) appeared to provide protection from Fas-mediated apoptosis because an MAPK kinase inhibitor (U0126) sensitized thyroid cells to anti-Fas antibody. In conclusion, Fas signaling is blocked in normal thyroid cells at a point after the activation of proximal caspases. Interferon-γ/IL-1β pretreatment sensitizes human thyroid cells to Fas-mediated apoptosis in a complex manner that overcomes this blockade through increased expression of cell surface Fas receptor, increases in proapoptotic molecules that result in mitochondrial activation, and late caspase cleavage. This process involves Bcl-2 family proteins and appears to be compatible with type II apoptosis regulation.

C6 glioma cells retrovirally engineered to express IL-18 and Fas exert FasL-dependent cytotoxicity against glioma formation

The decreased antitumor immune response significantly contributes to the progression of glioma. To evaluate whether the antitumor immunity is restored by stable co-expression of IL-18 and Fas receptor, we retrovirally introduced these two genes into rat C6 glioma cells. We found that IL-18-transduced glioma cells secreted IL-18 and induced PBMC IFN-gamma production in vitro. We also found that Fas-transduced glioma cells were susceptible to Fas-mediated apoptosis. In vivo, we found that IL-18 expression and Fas expression synergistically inhibited C6 cell tumorigenesis with the glioma cells being subcutaneously injected in rat flank. Furthermore, we found that co-expression of IL-18 and Fas also produced a marked survival advantage with the rats being intracerebrally implanted with the glioma cells. Finally, we demonstrated that FasL-dependent PBMC cytotoxicity participated in the anti-glioma immunity induced by IL-18 and Fas expression. Taken together, these findings demonstrate that increasing IL-18 production in tumor microenvironment and prompting functional Fas receptor expression of tumor cells could enhance FasL-dependent cytotoxic antitumor immunity.

TNF-related apoptosis-inducing ligand is involved in neutropenia of systemic lupus erythematosus

Neutropenia is a common laboratory finding in systemic lupus erythematosus (SLE). However, the molecular mechanism of SLE neutropenia has not been fully explained. In this study, we examined whether TNF-related apoptosis-inducing ligand (TRAIL) is involved in the pathogenesis of SLE neutropenia using samples from SLE patients. Serum TRAIL levels in SLE patients with neutropenia were significantly higher than those of SLE patients without neutropenia and healthy volunteers. Serum TRAIL levels showed a significant negative correlation with neutrophil counts in SLE patients. The expression of TRAIL receptor 3 was significantly lower in SLE patients with neutropenia than in patients without neutropenia or in healthy volunteers. Treatment with glucocorticoids negated the decrease of TRAIL receptor 3 expression on neutrophils of SLE patients. TRAIL may accelerate neutrophil apoptosis of neutrophils from SLE patients, and autologous T cells of SLE patients, which express TRAIL on surface, may kill autologous neutrophils. Interferon gamma and glucocorticoid modulated the expression of TRAIL on T cells of SLE patients and also modulated the expression of cellular Fas-associating protein with death domain–like interleukin-1β–converting enzyme (FLICE)–inhibitory protein (cFLIP), an inhibitor of death receptor signaling, in neutrophils. Thus, our results provide a novel insight into the molecular pathogenesis of SLE neutropenia.

The expression and role of Fas ligand in intestinal inflammation

Fas ligand (FasL) is involved in the pathogenesis of inflammatory diseases and immune privilege. We examined the expression of FasL in the enteric nervous system (ENS) in murine colitis and guinea-pig ileitis. We studied FasL immunoreactivity, functional integrity of the ENS, severity of colitis, and distribution of neutrophils in wild type and B6/gld mice that lack functional FasL. In ileitis, the distribution of FasL, CD4+ and CD8+ T cells was examined. FasL expression was increased in the ENS of wild type mice with colitis, but decreased labelling of nerve fibres was noted in B6/gld mice. Neutrophils were more abundant and widely distributed in B6/gld mice. Colitis was more severe and persistent in B6/gld mice 7 days after induction. Functional parameters of intestinal secretion and motility in B6/gld mice were the same as controls. In ileitis, FasL expression was increased in the guinea-pig ENS and returned to control levels following the resolution of inflammation. While T cells were not present in the ENS of controls, they were observed during inflammation, but were excluded from ganglia. The number of enteric neurons was unchanged over the course of inflammation. The expression of FasL is altered in intestinal inflammation and contributes to its resolution in experimental colitis.

Synthetic retinoids as inducers of apoptosis in ovarian carcinoma cell lines

Apoptosis is also known as programmed cell death. Apoptosis plays an essential role in maintaining normal tissue and cell physiology in multicellular organisms. Clearance of aberrant or pre-cancerous cells occurs through the induction of apoptosis. It has been reported that many tumors and tumor cell lines have dysfunctional apoptosis signaling, causing these tumors to escape immune monitoring and internal cellular control mechanisms. One potential cause of this dysfunctional apoptosis is the tumor suppressor p53, an important regulator of growth arrest and apoptosis that is mutated in over 50% of all cancers. Retinoids have great potential in the areas of cancer therapy and chemoprevention. While some tumor cells are sensitive to the growth inhibitory effects of natural retinoids such as all-trans-retinoic acid (ATRA), many ovarian tumor cells are not. 6-[3-(1-Admantyl)]-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) and fenretinide N-[4-hydroxyphenyl] retinamide (4-HPR) are conformationally restricted synthetic retinoids that induce growth arrest and apoptosis in both ATRA-sensitive and ATRA-resistant ovarian tumor cell lines. Recently, we have identified the molecular pathways of apoptosis induced by treatment of ovarian carcinoma cells with mutated p53 by CD437 and 4-HPR.

Hyperthyroidism

Hyperthyroidism is a pathological syndrome in which tissue is exposed to excessive amounts of circulating thyroid hormone. The most common cause of this syndrome is Graves' disease, followed by toxic multinodular goitre, and solitary hyperfunctioning nodules. Autoimmune postpartum and subacute thyroiditis, tumours that secrete thyrotropin, and drug-induced thyroid dysfunction, are also important causes. The diagnosis of hyperthyroidism is generally straightforward, with raised serum thyroid hormones and suppressed serum thyrotropin in almost all cases. Appropriate treatment of hyperthyroidism relies on identification of the underlying cause. Antithyroid drugs, radioactive iodine, and surgery are the traditional treatments for the three common forms of hyperthyroidism. Beta-adrenergic blocking agents are used in most patients for symptomatic relief, and might be the only treatment needed for thyroiditis, which is transient. The more unusual causes of hyperthyroidism, including struma ovarii, thyrotropin-secreting tumours, choriocarcinoma, and amiodarone-induced thyrotoxicosis are, more often than not, a challenge to diagnose and treat.

Selective induction of dendritic cells using granulocyte macrophage-colony stimulating factor, but not fms-like tyrosine kinase receptor 3-ligand, activates thyroglobulin-specific CD4+/CD25+ T cells and suppresses experimental autoimmune thyroiditis

Fms-like tyrosine kinase receptor 3-ligand (Flt3-L) and GM-CSF cause expansion of different subsets of dendritic cells and skew the immune response toward predominantly Th1 and Th2 type, respectively. In the present study, we investigated their effects on experimental autoimmune thyroiditis in CBA/J mice. Relative to mouse thyroglobulin (mTg) immunized controls, mTg-immunized mice treated with Flt3-L showed more severe thyroiditis characterized by enhanced lymphocytic infiltration of the thyroid, and IFN-gamma and IL-2 production. In contrast, mice treated with GM-CSF, either before or after immunization with mTg, showed suppressed T cell response to mTg and failed to develop thyroiditis. Lymphocytes from these mice, upon activation with mTg in vitro, produced higher levels of IL-4 and IL-10. Additionally, GM-CSF-treated mice showed an increase in the frequency of CD4(+)/CD25(+) T cells, which suppressed the mTg-specific T cell response. Neutralization of IL-10, but not IL-4, or depletion of CD4(+)/CD25(+) cells resulted in increased mTg-specific in vitro T cell proliferation suggesting that IL-10 produced by the Ag-specific CD4(+)/CD25(+) regulatory T cells might be critical for disease suppression. These results indicate that skewing immune response toward Th2, through selective activation of dendritic cells using GM-CSF, may have therapeutic potential in Th1 dominant autoimmune diseases including Hashimoto's thyroiditis.

Fas ligand gene polymorphisms are not associated with Hashimoto's thyroiditis and Graves' disease

Hashimoto's thyroiditis and Graves' disease represent the two most common autoimmune thyroid disorders. Whereas in Hashimoto's thyroiditis FasL expression causes thyrocytes to undergo apoptosis, additional anti-apoptotic molecules appear to protect these cells in Graves' disease. Mutations of the FasL gene were observed in systemic lupus erythematosus. Given its functional relevance for the pathogenesis of thyroid autoimmunity we wondered whether variants of the FasL gene play a role in Hashimoto's thyroiditis and Graves' disease. We genotyped families with at least one offspring affected by Hashimoto's thyroiditis (n = 86) and Graves' disease (n = 90) for two FasL gene polymorphisms (C -843 T in the promoter, A IVS2nt-124 G in intron 2). Extended transmission disequilibrium (ETDT) and chi(2) testing were performed. Neither polymorphism alone nor the promoter/intron 2 haplotypes (p = 0.91) were associated with Hashimoto's thyroiditis. No association with Graves' disease was observed for the promoter polymorphism (p = 0.91) and the intron 2 "A" allele (57.1%; p = 0.36) or the promoter/intron 2 haplotypes (p = 0.31). Moreover, intron 2 genotyping revealed no difference between an additional 251 patients with Graves' disease and 197 healthy controls (p = 0.37). Italian and German families did not differ for the studied polymorphisms. In conclusion, our data do not suggest common genetic FasL variants to significantly contribute to the pathogenesis of either Hashimoto's thyroiditis or Graves' disease.

Molecular sequelae of proteasome inhibition in human multiple myeloma cells

The proteasome inhibitor PS-341 inhibits IkappaB degradation, prevents NF-kappaB activation, and induces apoptosis in several types of cancer cells, including chemoresistant multiple myeloma (MM) cells. PS-341 has marked clinical activity even in the setting of relapsed refractory MM. However, PS-341-induced apoptotic cascade(s) are not yet fully defined. By using gene expression profiling, we characterized the molecular sequelae of PS-341 treatment in MM cells and further focused on molecular pathways responsible for the anticancer actions of this promising agent. The transcriptional profile of PS-341-treated cells involved down-regulation of growth/survival signaling pathways, and up-regulation of molecules implicated in proapoptotic cascades (which are both consistent with the proapoptotic effect of proteasome inhibition), as well as up-regulation of heat-shock proteins and ubiquitin/proteasome pathway members (which can correspond to stress responses against proteasome inhibition). Further studies on these pathways showed that PS-341 decreases the levels of several antiapoptotic proteins and triggers a dual apoptotic pathway of mitochondrial cytochrome c release and caspase-9 activation, as well as activation of Jun kinase and a Fas/caspase-8-dependent apoptotic pathway [which is inhibited by a dominant negative (decoy) Fas construct]. Stimulation with IGF-1, as well as overexpression of Bcl-2 or constitutively active Akt in MM cells also modestly attenuates PS-341-induced cell death, whereas inhibitors of the BH3 domain of Bcl-2 family members or the heat-shock protein 90 enhance tumor cell sensitivity to proteasome inhibition. These data provide both insight into the molecular mechanisms of antitumor activity of PS-341 and the rationale for future clinical trials of PS-341, in combination with conventional and novel therapies, to improve patient outcome in MM.

Regulation of Apo2L/tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in thyroid carcinoma cells

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)/Apo2 ligand selectively kills neoplastic cells, including thyroid carcinoma cells (Mitsiades et al: Thyroid carcinoma cells are resistant to FAS-mediated apoptosis but sensitive to tumor necrosis factor-related apoptosis-inducing ligand. Cancer Res 2000, 60:4122-41299). We investigated the mechanisms regulating Apo2L/TRAIL-induced apoptosis in thyroid carcinoma cells, as well as the impact of insulin-like growth factor (IGF)-1, interferon-gamma, and TNF-alpha. We found that the emergence of resistance to Apo2L/TRAIL, after prolonged incubation with this cytokine, was associated with increased levels of FLICE inhibitory protein (FLIP), and was overcome by cycloheximide and bisindolylmaleimide, that specifically down-regulated FLIP expression, as well as by transfection of a FLIP anti-sense oligonucleotide. IGF-1 activated Akt; up-regulated the caspase inhibitors FLIP, cIAP-2, XIAP, and survivin; and attenuated Apo2L/TRAIL-induced apoptosis. This effect was inhibited by the IGF-1 receptor neutralizing antibody aIR3, the PI-3K inhibitor wortmannin, and the heat shock protein-90 chaperone inhibitor geldanamycin. Transfection of constitutively active Akt protected from TRAIL. Conversely, interferon-gamma and TNF-alpha had a sensitizing effect. We conclude that FLIP may negatively regulate Apo2L/TRAIL-induced apoptosis in thyroid carcinomas. Microenvironmental paracrine survival factors, such as IGF-1, up-regulate caspase inhibitors, including FLIP, and protect from Apo2L/TRAIL in a PI-3K/Akt-dependent manner. T helper-1 cytokines and compounds that selectively abrogate the IGF-1 signaling pathway may be helpful adjunct agents in Apo2L/TRAIL-based anti-cancer therapeutic regimens.

Apoptotic signaling induced by immunomodulatory thalidomide analogs in human multiple myeloma cells: therapeutic implications

Thalidomide (Thal) achieves responses even in the setting of refractory multiple myeloma (MM). Although increased angiogenesis in MM bone marrow and the antiangiogenic effect of Thal formed the empiric basis for its use in MM, we have shown that Thal and its immunomodulatory analogs (IMiDs) directly induce apoptosis or growth arrest of MM cells, alter adhesion of MM cells to bone marrow stromal cells, inhibit the production of cytokines (interleukin-6 and vascular endothelial growth factor) in bone marrow, and stimulate natural killer cell anti-MM immunity. In the present study, we demonstrate that the IMiDs trigger activation of caspase-8, enhance MM cell sensitivity to Fas-induced apoptosis, and down-regulate nuclear factor (NF)-kappa B activity as well as expression of cellular inhibitor of apoptosis protein-2 and FLICE inhibitory protein. IMiDs also block the stimulatory effect of insulinlike growth factor-1 on NF-kappa B activity and potentiate the activity of TNF-related apoptosis-inducing ligand (TRAIL/Apo2L), dexamethasone, and proteasome inhibitor (PS-341) therapy. These studies both delineate the mechanism of action of IMiDs against MM cells in vitro and form the basis for clinical trials of these agents, alone and coupled with conventional and other novel therapies, to improve outcome in MM.