Anti-inflammatory effects of recombinant human PDCD5 (rhPDCD5) in a rat collagen-induced model of arthritis

PDCD5 as a Potential Biomarker for Improved Prediction of the Incidence and Remission for Patients with Rheumatoid Arthritis

INTRODUCTION

Rheumatoid arthritis (RA) often involves an altered T-cell subpopulation, higher levels of inflammatory cytokines, and auto-antibodies. This study investigated whether PDCD5 could be a biomarker to predict the incidence and remission of RA so as to guide the therapeutic management of clinical RA.

METHODS

One hundred fifty-two patients (41 being in both active status and stable remission status) who were newly diagnosed with RA and 38 healthy controls were enrolled. Basic clinical data were collected before using blood samples remaining in the clinic after routine complete blood count. The ability of PDCD5 and important indicators to predict the remission of RA was estimated based on receiver operating characteristic curve (ROC) analysis.

RESULTS

PDCD5 expression was found to be significantly increased in RA patients in active status in comparison with healthy controls or those in stable remission status. Compared with anti-CCP, ESR and DAS28 score, PDCD5 was of better predictive value with an AUC of 0.846 (95% CI 0.780-0.912) for RA remission. The incidence risk of RA increased with higher levels of PDCD5 (OR = 1.73, 95% CI = 1.45-1.98, P = 0.005) in multiple logistic regression analysis, with the risk increasing by 2.94-times for high-risk group in comparison with low-risk group (OR = 2.94, 95% CI = 2.35-4.62, P < 0.001). The association between PDCD5 and RA remission showed a similar result. For correlation analysis, significant associations were eventually found between PDCD5 and indicated genes (FOXP3, TNF-α, IL-17A, IFN-γ and IL-6) as well as several important clinical parameters including IgG, RF, CRP, ESR, anti-CCP and DAS28 score.

CONCLUSIONS

This study suggested that increased PDCD5 expression was significantly linked to the incidence and remission of RA. PDCD5 may be used as a novel biomarker for the prediction of RA incidence and remission, especially due to its potential involvement in the development of the condition.

[rhPDCD5 suppresses pro-inflammatory cytokine secretion and proliferation and induces apoptosis of activated lymphocytes from rats with collagen-induced arthritis]

OBJECTIVE

To investigate the effect of recombinant human PDCD5 (rhPDCD5) treatment in a rat model of bovine II collagen (CII)-induced arthritis (CIA) on inflammatory cytokine secretion, proliferation and apoptosis of activated lymphocytes and explore the mechanisms of rhPDCD5-induced immunosuppression on activated lymphocytes.

METHODS

Female Wistar rats were randomly divided into normal control group, CIA+ ovalbumin (OVA) group, CIA+ rhTNFR: Fc group, and CIA+rhPDCD5 group. The rats in the latter 3 groups received intraperitoneal injections of OVA (14 mg/kg), rhTNFR: Fc (3.5 mg/kg) or rhPDCD5 (14 mg/kg) from day 2 to day 26 following CII injection. On day 28, the spleens of the rats were harvested for preparing single cell suspensions of splenocytes, which were activated by CII (20μg/mL) or anti-CD3 (1μg/mL)+ anti-CD28 (2μg/mL) for 48 h and 72 h. The production of interferon-γ(IFN-γ) and interleukin-17A (IL-17A) by the activated lymphocytes was determined by ELISA of the culture supernatants. The proliferation and apoptosis of the activated lymphocytes were assessed using [³H]-thymidine incorporation assay and flow cytometry, respectively.

RESULTS

Compared with those in CIA + OVA group, IFN-γand IL-17A secretions by the activated lymphocytes from rhPDCD5-treated CIA rats significantly decreased. RhPDCD5 treatment of the CIA rats obviously suppressed the proliferation and promoted apoptosis of the lymphocytes activated by CII or by anti-CD3 + anti-CD28.

CONCLUSIONS

rhPDCD5 reduces pro-inflammatory cytokine secretion, inhibits the proliferation and promotes activation-induced cell death of activated CD4 ⁺ lymphocytes to produce immunosuppression in rat models of CIA.

Programmed cell death 5 transgenic mice attenuates adjuvant induced arthritis by 2 modifying the T lymphocytes balance

BACKGROUND

Programmed cell death 5 (PDCD5) is an apoptosis-related gene cloned from TF-1 cells whose primary biological functions are to promote apoptosis and immune regulation. The effects and mechanisms exerted by key mediators of arthritic inflammation remain unclear in PDCD5 transgenic (PDCD5 tg) mice.

RESULTS

In the current study, PDCD5 tg mice inhibited the progression of adjuvant-induced arthritis, specifically decreasing clinical signs and histological damage, compared with arthritis control mice. Additionally, the ratio of CD4⁺IFN-γ⁺ cells (Th1) and CD4⁺IL-17A⁺ cells (Th17), as well as the mRNA expression of the pro-inflammatory mediators IFN-γ, IL-6, IL-17A and TNF-α, were decreased in PDCD5 tg mice, while CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells and the anti-inflammatory mediators IL-4 and IL-10 were increased. Furthermore, PDCD5 tg mice demonstrated reduced serum levels of IFN-γ, IL-6, IL-17A and TNF-α and increased levels of IL-4.

CONCLUSIONS

Based on our data, PDCD5 exerts anti-inflammatory effects by modifying the T lymphocytes balance, inhibiting the production of pro-inflammatory mediators and promoting the secretion of anti-inflammatory cytokines, validating PDCD5 protein as a possible treatment for RA.

PDCD5 regulates cell proliferation, cell cycle progression and apoptosis

Programmed cell death (PDCD)5 is cloned from human leukemia cell line TF-1. PDCD5 is one of the members of the programmed cell death protein family that is frequently involved in tumor growth and apoptosis. To investigate the molecular and cellular functions of PDCD5, the present study established a PDCD5 stably overexpressing A431 cell line and examined the role of PDCD5 in cell proliferation, cell cycle progression and apoptosis. The data demonstrated that overexpression of PDCD5 significantly inhibited cell proliferation, induced cell cycle arrest at G2/M phase and apoptosis in A431 cells. The expression profiles of certain key regulators of these cellular events were further investigated, including P53, B cell lymphoma (BCL)-2, BCL-2 associated X protein (BAX) and caspase (CASP)3. The data demonstrated that at the transcript and protein levels, P53, BAX and CASP3 were all upregulated in the PDCD5 stably overexpressing A431 cells whereas BCL-2 was downregulated, indicating that PDCD5 acts as an important upstream regulator of P53, BCL-2, BAX and CASP3. The data suggest that PDCD5 regulates cell proliferation, cell cycle progression and apoptosis in A431 cells. PDCD5 may be a novel tumor suppressor gene, and may be potentially used for cancer treatment in the future.

Deletion of Pdcd5 in mice led to the deficiency of placenta development and embryonic lethality

Programmed cell death 5 (PDCD5) is an apoptosis promoter molecule that displays multiple biological activities. However, the function of PDCD5 in vivo has not yet been investigated. Here, we generated a Pdcd5 knockout mouse model to study the physiological role of PDCD5 in vivo. Knockout of the Pdcd5 gene resulted in embryonic lethality at mid-gestation. Histopathological analysis revealed dysplasia in both the LZs and JZs in Pdcd5^–/– placentas with defects in spongiotrophoblasts and trophoblast giant cells. Furthermore, Pdcd5^–/– embryos had impaired transplacental passage capacity. We also found that Pdcd5^–/– embryos exhibited cardiac abnormalities and defective liver development. The growth defect is linked to impaired placental development and may be caused by insufficient oxygen and nutrient transfer across the placenta. These findings were verified in vitro in Pdcd5 knockout mouse embryonic fibroblasts, which showed increased apoptosis and G0/G1 phase cell cycle arrest. Pdcd5 knockout decreased the Vegf and hepatocyte growth factor (Hgf) levels, downregulated the downstream Pik3ca–Akt–Mtor signal pathway and decreased cell survival. Collectively, our studies demonstrated that Pdcd5 knockout in mouse embryos results in placental defects and embryonic lethality.

Anti-arthritic effect of berberine on adjuvant-induced rheumatoid arthritis in rats

BACKGROUND

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease, which affects approximately 1% adult population in the worldwide.

AIM

The present study was to investigate the anti-arthritic effect of berberine and its involved mechanism in Freund's complete adjuvant (FCA) induced arthritis rats.

METHODS AND MATERIALS

Rats were divided randomly into control, FCA, tripterysium glycosides, berberine (75 and 150mg/kg). The apparent indicators, including changes of body weights, paw swelling degrees and arthritis indexes, were analyzed to evaluate anti-arthritic effect of berberine. The levels of IL-6, IL-10, IL-17 and TGF-β in serum were measured by ELISA. Histopathological changes and immunohistochemical expression of anti-IL-10 and anti-IL-17 antibodies in ankle joint tissues were examined.

RESULTS

Berberine obviously suppressed the severity of RA rats by attenuating the apparent indicators as mentioned above. Meanwhile, berberine significantly decreased the levels of IL-6 and IL-17, and increased the levels of IL-10 and TGF-β. Histopathological examinations indicated that berberine attenuated the synovial hyperplasia and inflammatory cell infiltration in joint tissues. In addition, immunohistochemical results showed that the amount of anti-IL-10 antibody increased, while the amount of anti-IL-17 antibody decreased in ankle tissues of arthritis rats.

CONCLUSIONS

Our results showed that berberine exerted a superior anti-arthritic effect and the mechanism maybe involve the balance between Treg and Th17 cells.

Overexpression of programmed cell death 5 in a mouse model of ovalbumin-induced allergic asthma

Background

Programmed cell death 5 (PDCD5) was first identified as an apoptosis-promoting protein and involved in some autoimmune diseases and inflammatory processes. Our previous study demonstrated greater expression of serum PDCD5 in asthmatic patients than controls. This study aimed to further explore the significance of PDCD5 in mice with induced allergic asthma.

Methods

We divided 16 female mice into 2 groups: control (n = 8) and allergen (ovalbumin, OVA)-challenged mice (n = 8). The modified ovalbumin inhalation method was used to generate the allergic asthma mouse model, and the impact of OVA was assessed by histology of lung tissue and morphometry. The number of cells in bronchoalveolar lavage fluid (BALF) was detected. Pulmonary function was measured by pressure sensors. PDCD5 and active caspase-3 levels were detected.

Results

The expression of PDCD5 was higher with OVA challenge than for controls (p < 0.05). PDCD5 level was correlated with number of inflammatory cells in BALF and lung function. Moreover, active caspase-3 level was increased in the OVA-challenged mice (p < 0.001) and correlated with PDCD5 level (p = 0.000).

Conclusions

These data demonstrate an association between level of PDCD5 and asthma severity and indicate that PDCD5 may play a role in allergic asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0317-y) contains supplementary material, which is available to authorized users.

The reduced PDCD5 protein is correlated with the degree of tumor differentiation in endometrioid endometrial carcinoma

Endometrial cancer is one of the most common malignancies in the female genital tract. Programmed cell death 5 (PDCD5) is a newly identified apoptosis related gene and plays an important role in the development of some human tumors. However, the expression and clinical significance of PDCD5 in endometrial cancer have not been fully elucidated. Here, we evaluated the expression of PDCD5 in endometrioid endometrial carcinoma and control endometrium by qRT-PCR, western blot and immunohistochemistry, and analyzed the associations of PDCD5 expression with clinicopathological parameters of patients. In addition, we detected the expression of PDCD5 in control endometrial glandular epithelial cells and endometrioid endometrial carcinoma-derived cell line KLE by immunocytochemistry. The results showed that PDCD5 protein mainly expressed in the cytoplasm of glandular epithelial cells and endometrial carcinoma cells, and there was a low level of PDCD5 expression in the nuclei of the above cells. Furthermore, PDCD5 protein level was significantly lower in endometrial carcinoma samples than that in control endometrium. The decreased PDCD5 expression was correlated with the tumor differentiation degree. It is clear that PDCD5 protein expression was lower in middle and low differentiated endometrial carcinoma compared with control endometrium and high differentiated endometrial carcinoma. However, there were no significant differences of PDCD5 expression between the proliferative phase and the secretory phase of control endometrium, as well as between high differentiated endometrial carcinoma and controls. The results were verified in control glandular epithelial cells and KLE cells by immunocytochemistry. Therefore, PDCD5 may play a key role in the pathogenesis of endometrial cancer and may be a novel target for diagnosis and treatment of endometrial cancer.

Cellular functions of programmed cell death 5

Programmed cell death 5 (PDCD5) was originally identified as an apoptosis-accelerating protein that is widely expressed and has been well conserved during the process of evolution. PDCD5 has complex biological functions, including programmed cell death and immune regulation. It can accelerate apoptosis in different type of cells in response to different stimuli. During this process, PDCD5 rapidly translocates from the cytoplasm to the nucleus. PDCD5 regulates the activities of TIP60, HDAC3, MDM2 and TP53 transcription factors. These proteins form part of a signaling network that is disrupted in most, if not all, cancer cells. Recent evidence suggests that PDCD5 participates in immune regulation by promoting regulatory T cell function via the PDCD5-TIP60-FOXP3 pathway. The stability and expression of PDCD5 are finely regulated by other molecules, such as NF-κB p65, OTUD5, YAF2 and DNAJB1. PDCD5 is phosphorylated by CK2 at Ser119, which is required for nuclear translocation in response to genotoxic stress. In this review, we describe what is known about PDCD5 and its cellular functions.