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Pain is one of the most challenging and stressful conditions to patients with sickle cell disease (SCD) and their clinicians. Patients with SCD start experiencing pain as early as 3 months old and continue having it throughout their lives. Although many aspects of the disease are well understood, little progress has been made in understanding and treating pain in SCD. This study aimed to investigate the functional involvement of Ca/calmodulin-dependent protein kinase II (CaMKIIα) in the persistent and refractory pain associated with SCD. We found that nonevoked ongoing pain as well as evoked hypersensitivity to mechanical and thermal stimuli were present in Berkeley sickle cell transgenic mice (BERK mice), but not nonsickle control littermates. Prominent activation of CaMKIIα was observed in the dorsal root ganglia and spinal cord dorsal horn region of BERK mice. Intrathecal administration of KN93, a selective inhibitor of CaMKII, significantly attenuated mechanical allodynia and heat hyperalgesia in BERK mice. Meanwhile, spinal inhibition of CaMKII elicited conditioned place preference in the BERK mice, indicating the contribution of CaMKII in the ongoing spontaneous pain of SCD. We further targeted CaMKIIα by siRNA knockdown. Both evoked pain and ongoing spontaneous pain were effectively attenuated in BERK mice. These findings elucidated, for the first time, an essential role of CaMKIIα as a cellular mechanism in the development and maintenance of spontaneous and evoked pain in SCD, which can potentially offer new targets for pharmacological intervention of pain in SCD. [ABSTRACT FROM AUTHOR]

Previous studies have shown that FXR is involved in glycolipid metabolism, tissue inflammation and regeneration in organs such as the liver, intestines and kidneys. Although FXR has been reported in cardiac tissue, its function in diabetic cardiomyopathy has not been reported. Here, we successfully constructed a diabetic mouse model of FXR-/- and evaluated the effects of FXR knockout on cardiac function in mice by measuring various indicators. We demonstrated that blood glucose levels in diabetic mice are significantly elevated in the case of FXR knockout. Our findings from cardiac ultrasound and tissue HE staining supported that FXR knockout aggravates diabetic cardiomyopathy. Masson staining of myocardial tissue and quantitative detection of α-SMA by qPCR suggest that FXR knockout exacerbates cardiac fibrosis in diabetic cardiomyopathy. Combined with the results of Oil Red staining and quantitative detection of triglycerides in fresh tissue blocks, we hypothesized that FXR knockout aggravates diabetes-induced cardiac lipid accumulation. Altogether our results revealed a role of the FXR in the diabetic cardiomyopathy, suggesting a possible novel target for the treatment of diabetic cardiomyopathy. [ABSTRACT FROM AUTHOR]