Refining the Baveno VI elastography criteria for the definition of compensated advanced chronic liver disease

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Blocking protein farnesyltransferase improves nuclear blebbing in mouse fibroblasts with a targeted Hutchinson-Gilford progeria syndrome mutation

Hutchinson-Gilford progeria syndrome (HGPS), a progeroid syndrome in children, is caused by mutations in LMNA (the gene for prelamin A and lamin C) that result in the deletion of 50 aa within prelamin A. In normal cells, prelamin A is a "CAAX protein" that is farnesylated and then processed further to generate mature lamin A, which is a structural protein of the nuclear lamina. The mutant prelamin A in HGPS, which is commonly called progerin, retains the CAAX motif that triggers farnesylation, but the 50-aa deletion prevents the subsequent processing to mature lamin A. The presence of progerin adversely affects the integrity of the nuclear lamina, resulting in misshapen nuclei and nuclear blebs. We hypothesized that interfering with protein farnesylation would block the targeting of progerin to the nuclear envelope, and we further hypothesized that the mislocalization of progerin away from the nuclear envelope would improve the nuclear blebbing phenotype. To approach this hypothesis, we created a gene-targeted mouse model of HGPS, generated genetically identical primary mouse embryonic fibroblasts, and we then examined the effect of a farnesyltransferase inhibitor on nuclear blebbing. The farnesyltransferase inhibitor mislocalized progerin away from the nuclear envelope to the nucleoplasm, as determined by immunofluoresence microscopy, and resulted in a striking improvement in nuclear blebbing (P < 0.0001 by chi2 statistic). These studies suggest a possible treatment strategy for HGPS.     

Gene therapy blockade of dorsal striatal p11 improves motor function and dyskinesia in parkinsonian mice

Complications of dopamine replacement for Parkinson’s disease (PD) can limit therapeutic options, leading to interest in identifying novel pathways that can be exploited to improve treatment. p11 (S100A10) is a cellular scaffold protein that binds to and potentiates the activity of various ion channels and neurotransmitter receptors. We have previously reported that p11 can influence ventral striatal function in models of depression and drug addiction, and thus we hypothesized that dorsal striatal p11 might mediate motor function and drug responses in parkinsonian mice. To focally inhibit p11 expression in the dorsal striatum, we injected an adeno-associated virus (AAV) vector producing a short hairpin RNA (AAV.sh.p11). This intervention reduced the impairment in motor function on forced tasks, such as rotarod and treadmill tests, caused by substantia nigra lesioning in mice. Measures of spontaneous movement and gait in an open-field test declined as expected in control lesioned mice, whereas AAV.sh.p11 mice remained at or near normal baseline. Mice with unilateral lesions were then challenged with l-dopa (levodopa) and various dopamine receptor agonists, and resulting rotational behaviors were significantly reduced after ipsilateral inhibition of dorsal striatal p11 expression. Finally, p11 knockdown in the dorsal striatum dramatically reduced l-dopa–induced abnormal involuntary movements compared with control mice. These data indicate that focal inhibition of p11 action in the dorsal striatum could be a promising PD therapeutic target to improve motor function while reducing l-dopa–induced dyskinesias.Pharmacologic replacement of depleted dopamine is the primary therapeutic approach to treating Parkinson’s disease (PD). Although this usually improves the major motor problems of this disorder, complications of medical therapy can often limit both dosing and effectiveness. Among the most common adverse effects limiting dopamine replacement therapy for PD is the development of abnormal involuntary movements (AIMs), also known as levodopa-induced dyskinesia (LID) (1). Treatment of LID usually requires reducing the dosage of dopaminergic medications to below the threshold for major complications, although certain pharmacotherapies or surgeries can improve LID as well (1). Understanding both the anatomic location and molecular pathways underlying dyskinesia responses to dopamine replacement therapy is necessary to develop improved therapies, which can reduce motor symptoms without this debilitating problem.Previous studies have identified certain signaling pathways that may influence the development of dyskinesia. The primary site of action of l-dopa (levodopa) on PD motor symptoms after conversion to dopamine is the dorsal striatum, owing to the loss of the normal dopaminergic inputs from the substantia nigra pars compacta (2). This same region has also been shown to be responsible for motor complications of l-dopa therapy, including LID. Specifically, neurons harboring the D1 dopamine receptor appear to be primarily involved in these responses (3–5). Furthermore, other signaling pathways, including the serotonin 5-HT1B receptor, seem to modulate the response of these neurons to dopamine replacement therapy (6, 7). Nonetheless, it has been difficult to identify potential therapeutic targets that both improve motor function and reduce dyskinesia.Here we demonstrate that dorsal striatal p11 is a key regulator of dopamine responses in PD. We previously reported that p11, a small adaptor protein also known as S100A10, binds to specific serotonin receptor subtypes, including 5-HT1B (8–10). Because activation of the 5-HT1B serotonin receptor (5-HT1BR) reduces dyskinesia, and p11 binds to 5-HT1BR and potentiates 5-HT1B activity, we hypothesized that dorsal striatal p11 may influence the response to dopamine replacement therapy. We found that inhibition of p11 expression in the dorsal striatum improved motor function in parkinsonian mice. Surprisingly, blockade of dorsal striatal p11 expression profoundly inhibited dyskinesias in response to chronic l-dopa treatment, to a greater extent than pharmacologic activation of 5-HT1B in controls. This indicates that inhibition of striatal p11 is a promising potential target to block dyskinesias while improving motor function in PD, and that these effects likely occur through a mechanism other than 5-HT1B.     

Body composition and newborn birthweight in pregnancies of adolescent and mature women

Teenage pregnancy has been associated with adverse effects for the mother and the newborn (NB). In order to compare body composition (BC) between adolescents (Ad) and mature women (MW) during pregnancy and to determine the difference in birthweight and perinatal morbidity, pregnant Ad (n = 40) and MW (n = 227) were studied. BC changes between the second and third trimesters were determined by multifrequency bioelectrical impedance analysis, and birthweight and NB morbidity were evaluated. During the second and third trimesters of the pregnancy, fat mass was lower in the Ad group [16 kg (13–19)] than in the MW group [22 kg (17–27)] (P < 0.01; median and quartiles 1–3). Fat‐free mass increased by 3.09 kg (2.29–4.20) and 2.20 kg (1.0–3.59) (P ≤ 0.01), and total body water increased by 2.77 L (0.84–4.49) vs. 2.04 L (0.55–3.89) (P = 0.36), in the Ad and MW groups, respectively (median and quartiles 1–3). Birthweight was not significantly different between NBs of Ad (3223 ± 399 g) and NBs of MW (3312 ± 427 g, P = 0.22). The youngest Ad (<18 year old, n = 8) had NB with lower birthweight than MW (3031 ± 503 g, P = 0.06). NBs of Ad mothers showed a non‐significant trend towards a higher rate of morbidity relative to the NBs of MW. In conclusion, the BC of Ad differs from that of MW during pregnancy. In addition, the NB infants of Ad mothers tended to have a lower birthweight than those from MW, a result that suggests that the Ad should be in strict prenatal control.