Fas/FasL mediated apoptosis of thyrocytes in Graves' disease

Associations between immune cell traits and autoimmune thyroid diseases: a bidirectional two-sample mendelian randomization study

Autoimmune thyroid diseases (AITDs), mainly including Graves' disease (GD) and Hashimoto's thyroiditis (HT), are common autoimmune disorders characterized by abnormal immune responses targeting the thyroid gland. We conducted a bidirectional two-sample MR analysis using the largest dataset of peripheral immune cell phenotypes from Sardinia, and the AITD dataset from the 10th round of the FinnGen and the UK Biobank project. Instrumental variables (IVs) were rigorously selected based on the three assumptions of MR and analyzed using the Wald ratio, inverse-variance weighted (IVW), MR-Egger, and weighted median methods. Additionally, sensitivity analyses were performed using Cochrane's Q, the Egger intercept, the MR-PRESSO, and the leave-one-out (LOO) method to ensure the robustness of the results. The Steiger test was utilized to identify and exclude potential reverse causation. The results showed that 3, 3, and 11 immune cell phenotypes were significantly associated with the risk of AITD. In GD, the proportion of naive CD4-CD8- (DN) T cells in T cells and the proportion of terminally differentiated CD4+T cells in T cells showed the strongest inducing and protective effects, respectively. In HT, lymphocyte count and CD45 on CD4+T cells showed the strongest inducing and protective effects, respectively. In autoimmune hypothyroidism, CD127 CD8+T cell count and terminally differentiated DN T cell count exhibited the strongest inducing and protective effects, respectively. Through MR analysis, our study provides direct genetic evidence of the impact of immune cell traits on AITD risk and lays the groundwork for potential therapeutic and diagnostic target discovery.

Differential effects of experimental hyperthyroidism on declined immunity of broiler chicken

Thyroid hormones (THs) are involved in the development of lymphoid organs and regulation of immune function in birds. However, their role as an immune-modulator in the hyperthyroid state is still debatable. To explore the interrelationship of thyroxine (T₄ ) and the immune system, chicks were divided into three groups. Group I was comprised of control birds, who received the basal diet while group II and III were given diets supplemented with 5 μg and 10 μg thyroxine/kg feed, respectively, from 15 to 28 days of age. Cell-mediated immune response was evaluated through in vitro abdominal macrophage phagocytosis assay, macrophage nitric oxide (NO) production, heterophil-to-lymphocyte (H:L) ratio and delayed-type hypersensitivity response against phytohemagglutinin (PHA). Humoural immune response was assessed through serum IgG and IgM antibody production against sheep red blood cells (SRBCs) and antibody production against infectious bronchitis virus (IBV). Sampling was carried out at 7, 14 and 21 days of treatment. Results have shown higher levels (p < .001) of circulating T₄ in both treatment groups compared to the control group. There was a lower (p < .05) macrophage engulfment percentage, an increase in H:L ratio (p < .001) in treated birds, while their NO production remained higher (p < .05) in thyroxine supplemented groups after bacterial lipopolysaccharide stimulation. The humoural immune response revealed a significant decline (p < .001) in IgG, IgM antibody production against SRBCs but IBV circulating antibodies increased with age. In conclusion, hyperthyroidism has a strong co-relation with decreased immune performance of birds.

[Molecular biological markers for proliferation, apoptosis, and angiogenesis in diffuse toxic goiter]

The pathogenesis of diffuse toxic goiter has not yet been fully understood. The literature increasing commonly focusses on the issues related to the processes occurring in the thyroid gland itself: proliferation, apoptosis, and angiogenesis.

AIM

to investigate clinical and laboratory parameters, as well as the expression of Ki-67, Bcl-2, Bax, Fas-L, CD34, VEGF, and FGF proteins in various postoperative outcomes of patients operated on for diffuse toxic goiter.

SUBJECTS AND METHODS

The investigation enrolled 24 women who had undergone surgery using the technique described by E.S. Drachinskaya. Immunohistochemical tests were carried out according to the standard protocol. The expression of Ki-67, Bcl-2, Bax, Fas-L, CD 34, VEGF, angiopoietin, and FGF proteins was determined.

RESULTS

The patients with postoperative thyrotoxicosis were ascertained to have a significantly greater expression of anti-apoptotic protein Bcl-2, proliferation marker Ki-67, vascular factors (FGF, VEGF), and CD 34.

CONCLUSION

The relative expression area of the anti-apoptotic protein Bcl-2 of more than 2.19 or the proliferation protein Ki-67 of more than 1.059 was found to predict the development of postoperative thyrotoxicosis with an accuracy of higher than 85%.

The expression of microvesicles in the blood of patients with Graves' disease and its relationship to treatment

OBJECTIVE

Graves' disease (GD) is an autoimmune disease characterized by the presence of circulating autoantibodies against thyroid-stimulating hormone (TSH) receptor. Despite extensive research, the pathogenic mechanisms remain unclear. Immune responses associated with the disease may lead to cell activation/apoptosis and the release of microvesicles (MVs) into the circulation. MVs can display biological activities which may aggravate GD further. We studied immune mechanisms in GD by investigating the numbers and phenotype of circulating MVs in patients before and after antithyroid therapy with thiamazole.

PATIENTS AND MEASUREMENTS

Samples were obtained from 15 patients with GD in the acute phase of hyperthyroidism and following 17-26 months treatment and 14 healthy controls. MVs from platelets, endothelial cells and monocytes exposing inflammation/activation markers (P-selectin, CD40 ligand, E-selectin and HMGB1) and MVs containing nuclear molecules were measured with flow cytometry.

RESULTS

Patients had elevated baseline values of MVs (P < 0·001 for all types of MVs), while the levels decreased during thiamazole treatment (P < 0·05 for all types of MVs). The majority of MV populations remained, however, significantly higher in patients after treatment compared to levels in controls.

CONCLUSIONS

GD patients have elevated levels of MVs that carry molecules with potential biological activities. MVs are significantly reduced after antithyroid treatment with thiamazole but still higher compared to levels in healthy controls. Assessment of MV levels and pattern may therefore provide additional information on underlying immune disturbances not obtained by measurements of hormone levels alone.

Thyroid hormones as modulators of immune activities at the cellular level

BACKGROUND

Increasing evidence suggests that thyroid hormones, L-thyroxine (T(4)) and 3,3',5-triiodo-L-thyronine (T(3)), are modulators of the immune response. In monocytes, macrophages, leukocytes, natural killer cells, and lymphocytes, a wide range of immune functions such as chemotaxis, phagocytosis, generation of reactive oxygen species (ROS), and cytokine synthesis and release are altered under hypo- and hyperthyroid conditions.

SUMMARY

Hyperthyroidism decreases the proinflammatory activities of monocytes and macrophages, whereas enhancement of phagocytosis and increased levels of ROS may occur during hypothyroidism. The expression of proinflammatory molecules such as macrophage inflammatory protein-1α and interleukin-1β increases in hypothyroidism. However, in Kupffer cells, proinflammatory activities such as the respiratory burst, nitric oxide synthase activity, and tumor necrosis factor-α expression may result from increased T(3) levels. Thyroid hormones also affect natural killer cell activity and cell-mediated immune responses. Still, for many immune cells no clear correlation has been found so far between abnormally high or low T(3) or T(4) levels and the effects observed on the immune responses.

CONCLUSIONS

In this review we outline the contributions of thyroid hormones to different aspects of innate and adaptive immune responses. The relationship between thyroid hormones and immune cells is complex and T(3) and T(4) may modulate immune responses through both genomic and nongenomic mechanisms. Future studies of the molecular signaling mechanisms involved in this cross-talk between thyroid hormones and the immune system may support development of new strategies to improve clinical immune responses.

Fascaplysin exert anti-tumor effects through apoptotic and anti-angiogenesis pathways in sarcoma mice model

Previous studies indicated that fascaplysin derived from marine sponge can induce tumor cell death by apoptosis and possesses anti-angiogenesis activity. In order to verify these two effects in animal model and to identify action mechanisms, we established a sarcoma mice model, and treated mice with fascaplysin for 10 days. The tumor tissues were examined morphologically and immunohistochemically. The differential gene expression was also investigated by mRNA array. Fascaplysin treatment resulted in a significant suppression of tumor growth. Typical apoptotic phenomena were observed by transmission electron microscope and histological detection. Tissue sections were stained with monoclonal antibody directed to proliferating cell nuclear antigen (PCNA) and CD31. The decreased PCNA and CD31 antigen staining indicate the reduction of tumor cell proliferation and tumor vasculature property of fascaplysin in vivo. Microarrays were used to examine the gene expression profiles of tumors on CapitalBio mouse genome oligo array. The regulated genes analyzed from the expression level showed overlapping gene ontology (GO) categories and pathway mapping. Our findings indicate that cell cycle arrest, apoptosis, regulation of actin cytoskeleton, and cell adhesion all play important roles in the onset of fascaplysin. Detailed analysis by real time PCR of key genes confirmed the experimental results of microarrays. From these findings, it can be considered that fascaplysin can inhibit the growth of S180 cell implanted tumor, and the action mechanisms may involve in apoptosis, anti-angiogenesis, or cell cycle arrest.

The main product of specialized tissues regulates cell life and may cause neoplastic transformation

Many tissues and cells in vertebrates are highly specialized and devoted to a single function through the action of a single molecule, that we call the "main product" (MP) of the cell. The hypothesis here proposed is that these MPs control all aspects of the cell life, namely activity, division, differentiation and apoptosis. Evidences supporting this hypothesis are reported for the immune system, pancreatic beta-cells, melanocytes, connective tissues, thyroid cells, skin and erythroid cells. In all cases cell division and differentiation is promoted by a normal activity of the MP, while hyperactivity leads to cell apoptosis. Evidences are also provided that alterations of the activity of the MP may elicit pathological disorders; in particular mutations altering the structure of the MP may elicit tumoural transformation.

Inhibitory effect of Kangjia Pill on thyrocyte proliferation in rat goiter model

OBJECTIVE

To investigate the inhibitory effects of Kangjia Pill (KJP) on the cell proliferation in rat goiter model induced by methimazole (MMI).

METHODS

Fifty-six Wistar rats were randomly divided into four groups: the normal group, MMI model group (MMI), low dose of KJP group (LKJP), and high dose of KJP (HKJP). Except the normal group (20 rats), the other groups (12 rats in each) were given 0.04% (w/v) MMI through the drinking water until the end of the experiment. One week later, the rats in the LKJP and HKJP groups were given KJP by gastrogavage at the dose of 250 mg/(kg x d) and 1,000 mg/(kg x d), respectively for 12 weeks. The relative thyroid weight (mg/100 g body weight) of each rat was accessed. The expression of proliferating cell nuclear antigen (PCNA) was determined by immunohistochemistry, and the correlation analysis between the PCNA positive thyrocytes and the relative thyroid weight was performed. The expressions of PCNA and cyclin D1 were examined with Western blotting.

RESULTS

After KJP treatment for 12 weeks, compared with the MMI group, the relative thyroid weight of the HKJP group decreased significantly, and the positive thyrocyte populations of PCNA in the two KJP groups reduced markedly (all P<0.05). The correlation analysis showed that PCNA was closely correlated with thyrocyte proliferation (r=0.685, P<0.05). KJP significantly decreased the protein expression of PCNA and cyclin D1 in the thyroid specimens (P<0.05), the high dose showed better effects.

CONCLUSION

KJP played a therapeutic role via inhibiting cell proliferation in the rat goitrous glands.

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.

Prevalence of interrelated autoantibodies in thyroid diseases and autoimmune disorders

OBJECTIVE

We determined the autoantibody profile in autoimmune thyroid diseases (AITD) and examined the distribution of thyroid-related autoantibodies in other autoimmune disorders.

METHODS

We tested sera from 234 patients with Graves' disease (GD), 130 with Hashimoto's thyroiditis (HT), 249 with other autoimmune diseases, and 50 healthy controls by enzyme-linked immunosorbent assay or radioimmunoassay.

RESULTS

Autoantibodies except TSH receptor antibody (Ab), anti-thyroglobulin (Tg) Ab and anti-thyroid peroxidase (TPO) Ab were not significantly prevalent in patients with AITD despite a significantly high elevation of thyroid-related Ab. Significant prevalence of autoantibodies related to AITD was observed in type 1 diabetes patients. Elevation of anti-Tg Ab was seen in patients with primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH), and anti-TPO Ab was elevated in patients with PBC. Although the prevalence of anti-acetylcholine receptor Ab and systemic lupus erythematosus (SLE)- related Ab was significant in AIH, primary Sjögren's syndrome (pSS)-related Ab were also found in both liver diseases. In myasthenia gravis (MG) patients, thyroid-related Ab and pSS-related Ab were detected in both MG groups, although SLE-related Ab were limited to the anti-muscle specific kinase Ab-positive MG patients. In patients with connective tissue diseases, anti- Tg Ab and anti-TPO Ab were significantly prevalent.

CONCLUSION

Thyroid-related Ab were significantly elevated in all autoimmune diseases. Conversely, the elevations of Ab were not significant in the patients with AITD, suggesting a close relationship between AITD and other immune-mediated diseases.

Intrathyroidal CD4+ T lymphocytes express high levels of Fas and CD4+ CD8+ macrophages/dendritic cells express Fas ligand in autoimmune thyroid disease

In autoimmune thyroid disease (AITD), the proportion of CD4 lymphocytes is lower in the thyroid than in the peripheral blood. We examined both Fas and Fas ligand (FasL) expression in lymphocyte subsets and nonlymphoid mononuclear cells including monocytes, macrophages, and dendritic cells (M/DCs) in both peripheral blood and thyroid specimens from 11 patients with Graves' disease and 1 with Hashimoto's disease by three-color flow cytometry. Proportions and intensities of Fas expression were increased in CD4 single-positive (SP) (CD4(+) CD8(-)), CD8 SP (CD8(+) CD4(-) ), and CD4(+) CD8(+) double-positive (DP) lymphocytes in AITD thyroids compared to those in blood, and were much higher in CD4(+) (CD4 SP and DP) lymphocytes than in CD8 SP lymphocytes in the thyroid. In the blood, most M/DCs expressed only CD4, but approximately 60% of M/DCs expressed both CD4 and CD8 in AITD thyroid. The proportion of DP M/DCs expressing FasL was higher in thyroid than in blood; proportion and intensity of FasL expression were much higher in DP M/DCs than in CD4 SP and CD8 SP M/DCs in the thyroid. These data indicate that increased Fas expression in intrathyroidal CD4(+) T lymphocytes may be the cause of CD4 lymphocyte reduction in AITD thyroid, and that intrathyroid DP M/DCs with high FasL expression may be related to the reduction in AITD.

Th1 and Th2 serum cytokine profiles characterize patients with Hashimoto's thyroiditis (Th1) and Graves' disease (Th2)

OBJECTIVES

The aim of this study was to document the pattern of immune response, assessed by the measurement of both Th1 and Th2 serum cytokines, in patients suffering from autoimmune thyroid disease and toxic nodular goiter.

METHODS

Both Th1 and Th2 serum cytokine levels were assayed in patients suffering from Graves' disease (GD, n = 25), Hashimoto's thyroiditis (HT, n = 21), and toxic nodular goiter (TNG, n = 7) and compared with corresponding levels of 25 healthy controls. Serum concentrations of IL-2, IL-1 beta, INF-gamma, TNF-alpha, IL-12, IL-15, IL-10, IL-18, IL-4 and IL-5 were assayed in fasting serum samples.

RESULTS

It was found that patients with HT had higher IL-2 serum levels (12.16 +/- 0.66 pg/ml) compared to patients with TNG (9.25 +/- 0.84 pg/ml), GD (7.86 +/- 0.30 pg/ml) and controls (7.36 +/- 0.45 pg/ml; p = 0.0001), higher INF-gamma levels (7.60 +/- 0.33 pg/ml) compared to patients with TNG (5.77 +/- 0.55 pg/ml), GD (5.74 +/- 0.24 pg/ml) and controls (5.09 +/- 0.27 pg/ml; p = 0.0009), higher IL-12 levels (3.57 +/- 0.19 pg/ml) compared to patients with TNG (2.57 +/- 0.21 pg/ml), GD (2.48 +/- 0.13 pg/ml) and controls (2.59 +/- 0.23 pg/ml; p = 0.004), and higher IL-18 levels (27.52 +/- 1.75 pg/ml) compared to patients with TNG (18.71 +/- 2.24 pg/ml), GD (15.44 +/- 1.39 pg/ml) and controls (15.16 +/- 1.62 pg/ml; p = 0.0002). In contrast, patients with GD had higher serum levels of IL-4 (4.11 +/- 0.33 pg/ml) compared to patients with HT (3.0 +/- 0.16; p = 0.02) and higher IL-5 levels (4.22 +/- 0.30 pg/ml) compared to patients with TNG (3.21 +/- 0.58 pg/ml), HT (2.75 +/- 0.16 pg/ml) and controls (2.0 +/- 0.19 pg/ml; p = 0.0001). Patients had lower IL-1 beta serum levels (TNG 2.45 +/- 0.20, HT 2.52 +/- 0.14, GD 2.68 +/- 0.12 pg/ml) compared to controls (3.6 +/- 0.20 pg/ml; p = 0.008).

CONCLUSIONS

The above findings suggest that a Th1 pattern of immune response characteristic of cellular immunity is dominant in HT, whereas the predominance of Th2 cytokines in GD indicates a humoral pattern of immune reaction.

Regulation of apoptosis in endocrine autoimmunity: insights from Hashimoto's thyroiditis and Graves' disease

Dysregulation of apoptosis is associated with the pathogenesis of organ-specific autoimmune diseases, through altered target organ susceptibility. Apoptosis signaling pathways can be initiated through activation of death receptors such as Fas. A comparative analysis of the expression of Fas and FasL, the antiapoptotic molecule Bcl-2, and apoptosis in both thyrocytes and thyroid-infiltrating lymphocytes (TILs) from patients with either Graves' disease (GD) or Hashimoto's thyroiditis (HT) was performed. GD thyrocytes expressed less Fas than HT thyrocytes, whereas GD TILs had higher levels of Fas and FasL than HT TILs. GD thyrocytes expressed higher levels of Bcl-2 compared with HT thyrocytes. The opposite pattern was observed in GD (low Bcl-2) and HT (high Bcl-2) TILs. Consistently, thyrocyte apoptosis was marked in HT and poor in GD thyroids, and TIL apoptosis was marked in GD and poor in HT. Our findings suggest that in GD thyroid the regulation of Fas/FasL/Bcl-2 favors apoptosis of infiltrating lymphocytes. Moreover, the reduced levels of Fas/FasL and increased levels of Bcl-2 should favor thyrocyte survival and hypertrophy associated with stimulatory thyroid-stimulating hormone receptor antibodies. In contrast, the regulation of Fas/FasL/Bcl-2 expression in HT can promote thyrocyte apoptosis via homophylic Fas-FasL interactions, and a gradual reduction in thyrocyte numbers leading to hypothyroidism. Fas-mediated apoptosis may be a general mechanism of cell damage in destructive organ-specific autoimmunity.

Effect of iodide on Fas, Fas-ligand and Bcl-w mRNA expression in thyroid of NOD mice pretreated with methimazole

Nonobese diabetic (NOD) mice and a derived strain, NOD.H.2h4, have been used as a model for experimental spontaneous thyroiditis and thyroiditis induced by iodide excess after a goiter-inducing period. Some authors have proposed that iodide, given after methimazole or propylthiouracil, is capable of inducing apoptosis in thyroid cells and that anti-thyroid drugs can modulate the expression of apoptosis components such as Fas and its ligand (Fas-L). Here we evaluated the effect of potassium iodide (20 microg/animal for 4 days, i.p.) given to NOD mice at the 10th week of life after exposure to methimazole (1 mg/ml) in drinking water from the 4th to the 10th week of life. Fas, Fas-L and Bcl-w expression were analyzed semiquantitatively by RT-PCR immediately after potassium iodide administration (group MI44D) or at week 32 (MI32S). Control groups were added at 10 (C10) and 32 weeks (C32), as well as a group that received only methimazole (CM10). An increase in the expression of Fas-L and Bcl-w (P<0.01, ANOVA) was observed in animals of group MI44D, while Fas was expressed at higher levels (P = 0.02) in group C32 (72.89 +/- 47.09 arbitrary units) when compared to group C10 (10.8 +/- 8.55 arbitrary units). Thus, the analysis of Fas-L and Bcl-w expression in the MI44D group and Fas in group C32 allowed us to detect two different patterns of expression of these apoptosis components in thyroid tissue of NOD mice.

Expression and regulation of Fas and Fas ligand on thyrocytes and infiltrating cells during induction and resolution of granulomatous experimental autoimmune thyroiditis

Granulomatous experimental autoimmune thyroiditis (G-EAT) is induced by mouse thyroglobulin-sensitized spleen cells activated in vitro with mouse thyroglobulin, anti-IL-2R, and IL-12. G-EAT lesions reach maximal severity 19-21 days after cell transfer, and lesions almost completely resolve by day 35. Depletion of CD8+ cells delays resolution and reduces Fas ligand (FasL) mRNA expression in thyroids. This study was undertaken to analyze Fas and FasL protein expression in the thyroid during induction and resolution of G-EAT and to determine whether CD8+ cells might regulate Fas or FasL expression in the thyroid. Fas and FasL expression was analyzed by immunohistochemical staining or in situ hybridization in thyroids of mice with or without depletion of CD8+ cells. Fas and FasL proteins were not detectable in normal thyroids, but expression of both proteins increased during development of G-EAT. Fas was expressed primarily by inflammatory cells; some enlarged thyrocytes were also Fas+. Thyrocytes had intense FasL immunoreactvity, and many CD8+ cells were also FasL positive. Depletion of CD8+ cells resulted in decreased FasL expression by thyrocytes and inflammatory cells, but had no effect on Fas expression. TUNEL assay detected many apoptotic inflammatory cells in proximity to thyrocytes. CD8-depleted thyroids had ongoing inflammation with fewer apoptotic infiltrating cells at day 35. Administration of a neutralizing anti-FasL mAb had no apparent effects on development of G-EAT, but anti-FasL was as effective as anti-CD8 in preventing G-EAT resolution. These results suggested that CD8+ T cells and thyrocytes may kill inflammatory cells through the Fas pathway, contributing to G-EAT resolution.