Investigation for the possibility of CaMKII activity modulation for the therapeutic optical in rheumatoid arthritis

类风湿性关节炎（RA）的发病机制是细胞增殖和凋亡的双重抵抗。其中，我们关注PI 3 K/Akt通路的重要性，在最近的2年里，我们试图研究CaMK II通路的作用。培养的FLS表达CaMK Ⅱ γ和δ，尤其是δ亚型。CaMK Ⅱ化学抑制剂KN 93的加入显著增加了FLS对TRAIL和抗Fas抗体的凋亡敏感性。另外的实验表明，CaMK II诱导的凋亡敏感性现象是通过Akt介导的。CaMKII是一种被Ca离子内流激活的酶。Ca离子内流还激活PADI，PADI是肽瓜氨酸的转录后机制的必需酶。瓜氨酸肽的转录后机制被认为是RA患者产生抗CCP抗体（RA特异性自身抗体）的关键。然而，我们不能检测到瓜氨酸肽培养FLS响应钙离子流入，促炎cytoltines或促凋亡刺激。因此，我们使用人细胞系HL-60进行了实验。HL-60表达CaMK Ⅱ γ亚型。在ATRA诱导HL-60细胞向粒系分化的过程中，PADI 4、瓜氨酸化肽和Akt磷酸化均显著表达。根据近2年的研究结果，CaMK Ⅱ与FLS细胞凋亡有一定的相关性。考虑到CaMKII和Akt之间可能的串扰，CaMKII、Akt和肽瓜氨酸酶过程之间似乎存在另一种串扰。这些机制被认为是RA的重要研究问题，其加强了CaMKII在RA中作为靶分子的作用。

The remarkable proliferation as well as apoptosis resistance are crucial for rheumatoid arthritis (RA). Among them, we have focused on the importance of PI3K/Akt pathway, and in the current 2 years, we have tried to investigate the role of CaMKII pathway. FLS in culture expressed CaMKII γ and δ, especially δ isoform. The addition of CaMKII chemical inhibitor, KN93, significantly augmented apoptosis sensitivity of FLS in response to TRAIL and anti-Fas antibody. The additional experiment showed that CaMKII-induced phenomena of apoptosis sensitivity are mediated through Akt. CaMKII is an enzyme that is activated by Ca ion influx. Ca ion influx also activates PADI, which is an essential enzyme for post-transcriptional mechanism of peptide citrullination. Post-transcriptional mechanism of peptide citrullination is thought to be crucial for anti-CCP antibodies production in patients with RA, a RA-specific autoantibodies. However, we could not detect the citrullinated peptides in cultured FLS in response to Ca ion influx, pro-inflammatory cytoltines or pro-apoptotic stimuli. Thus, we conducted the experiment by the use of human cell line, HL-60. HL-60 expressed CaMKII γ isoform. A significant expression of PADI4, citrullinated peptides and Akt phosphorylation was found during the course of granulocyte-lineage differentiation of HL-60 by ATRA According to the results obtained in the current 2 years, an association between CaMKII and FLS apoptosis is demonstrated. Considering a possible cross-talk between CaMKII and Akt, another cross-talk among CaMKII, Akt and the peptide citrullination process appears to be present. These mechanisms are thought to be important research issue of RA that strengthens a role of CaMKII for a target molecule in RA.