GFAP hyperpalmitoylation exacerbates astrogliosis and neurodegenerative pathology in PPT1-deficient mice.

The homeostasis of protein palmitoylation and depalmitoylation is essential for proper physiological functions in various tissues, in particular the central nervous system (CNS). The dysfunction of PPT1 (PPT1-KI, infantile neuronal ceroid lipofuscinosis [INCL] mouse model), which catalyze the depalmitoylation process, results in serious neurodegeneration accompanied by severe astrogliosis in the brain. Endeavoring to determine critical factors that might account for the pathogenesis in CNS by palm-proteomics, glial fibrillary acidic protein (GFAP) was spotted, indicating that GFAP is probably palmitoylated. Questions concerning if GFAP is indeed palmitoylated in vivo and how palmitoylation of GFAP might participate in neural pathology remain unexplored and are waiting to be investigated. Here we show that GFAP is readily palmitoylated in vitro and in vivo; specifically, cysteine-291 is the unique palmitoylated residue in GFAP. Interestingly, it was found that palmitoylated GFAP promotes astrocyte proliferation in vitro. Furthermore, we showed that PPT1 depalmitoylates GFAP, and the level of palmitoylated GFAP is overwhelmingly up-regulated in PPT1-knockin mice, which lead us to speculate that the elevated level of palmitoylated GFAP might accelerate astrocyte proliferation in vivo and ultimately led to astrogliosis in INCL. Indeed, blocking palmitoylation by mutating cysteine-291 into alanine in GFAP attenuate astrogliosis, and remarkably, the concurrent neurodegenerative pathology in PPT1-knockin mice. Together, these findings demonstrate that hyperpalmitoylated GFAP plays critical roles in regulating the pathogenesis of astrogliosis and neurodegeneration in the CNS, and most importantly, pinpointing that cysteine-291 in GFAP might be a valuable pharmaceutical target for treating INCL and other potential neurodegenerative diseases.

Globular adiponectin regulates energy homeostasis through AMP-activated protein kinase-acetyl-CoA carboxylase (AMPK/ACC) pathway in the hypothalamus.

Adiponectin is a newly researched adipokine which participates in the regulation of energy homeostasis. AMP-activated protein kinase (AMPK) represents an energy sensor that responds to hormone and nutrition status in vivo and exerts a regulatory effect in the hypothalamus and multiple peripheral tissues. We investigated the possible mechanisms involved in appetite regulation by adiponectin in vitro with GT1-7 cells, a mouse immortalized hypothalamic neuron. The results showed that adiponectin increased the phosphorylation of AMPK, activated AMPK phosphorylated and inactivated acetyl-CoA carboxylase (ACC), and subsequently increased expression of agouti-related peptide (AgRP) mRNA. Our results also indicated that adiponectin had no effect on signal transducer and activator of transcription (STAT3). Together these findings suggest that adiponectin regulated energy homeostasis through the AMPK/ACC pathway but not the JAK/STAT3 pathway in the hypothalamus.

[Comparison of clinical effect of two different Kirschner wire fixations after closed reduction on supracondylar fracture of humerus in children with Gartlandâ ¡and â ¢].

OBJECTIVE: To compare clinical effect of Kirschner wire radial sector fixation and bilateral ulnar radial cross fixation in treating supracondylar fracture of humerus in children after closed reduction. METHODS: From March 2017 to December 2018, 60 children with supracondylar fracture of humerus treated with closed reduction and Kirschner wire fixation were analyzed retrospectively, and divided into two groups according to different needling methods. Thirty patients in radial three needles fan fixation group (group A), including 19 males and 11 females, aged from 2 to 10 years old with an average of (5.00±2.10) years old, 21 patients were typeⅡ and 9 patients were typeⅢ according to Gartland classification. Thirty patients in cross fixationwith 3 needles on both ulnar and radial side group(group B), including 22 males and 8 females, aged from 1 to 9 years old with an average of(5.13±2.08) years old, 19 patients were typeⅡand 11 patients were typeⅢ. Healing time of fracture, postoperative complications, elbow flexion and extension activity, forearm rotation activity recovery, elbow carrying angle and angle loss after operation between two groups were observed and compared. Mayo Elbow function score at the final following up was used to evaluate clinical efficacy. RESULTS: All patients were followed up, while there were no significant difference in follow-up time and fracture healing time between two groups (P>0.05);there was 1 patient occurred iatrogenic ulnar nerve injury in group A, 9 patients in group B, and there was difference between two groups (P<0.01);2 patients in group A occurred mild displacement and 1 patient in group B, while no significant difference between two groups(P>0.05). No cubitus varus deformity, needle infection, osteofascial compartment syndrome and myositis ossificans occurred. There was no significant difference in elbow flexion, extension activity, and forearm rotation activity between two groups at 3 months after operation(P>0.05); there was no significant difference in elbow carrying angle and its loss angle between two groups at 3 and 6 months after operation (P>0.05);there was also no significant difference in Mayo Elbow function score and efficacy evaluation at the final follow-up (P>0.05). CONCLUSION: Closed reduction and Kirschner wire at the early stage of fracture has advantages of less trauma, easy reduction, stable fixation, and early functional exercise. The risk of iatrogenic ulnar nerve injury caused by fan-shaped fixation of three radial needles is less than that of cross fixation of three radial needles.