Mutant COMP shapes growth and development of skull and facial structures in mice and humans.

BACKGROUND: Cartilage oligomeric matrix protein (COMP) is an important extracellular matrix protein primarily functioning in the musculoskeletal tissues and especially endochondral bone growth. Mutations in COMP cause the skeletal dysplasia pseudoachondroplasia (PSACH) that is characterized by short limbs and fingers, joint laxity, and abnormalities but a striking lack of skull and facial abnormalities. METHODS: This study examined both mice and humans to determine how mutant-COMP affects face and skull growth. RESULTS: Mutant COMP (MT-COMP) mice were phenotypically distinct. Snout length and skull height were diminished in MT-COMP mouse and the face more closely resembled younger controls. Three-dimensional facial measurements of PSACH faces showed widely spaced eyes, reduced lower facial height, and decreased nasal protrusion, which correlated with a more juvenile appearing face. Neither MT-COMP mice nor PSACH individuals show midface hypoplasia usually associated with abnormal endochondral bone growth. MT-COMP mice do show delayed endochondral and membranous skull ossification that normalizes with age. CONCLUSION: Therefore, mutant-COMP affects both endochondral and intramembranous bones of the skull resulting in a reduction of the nose and lower facial height in mice and humans, in addition to its well-defined role in the growth plate chondrocytes.

Expression analysis of Lrrk1, Lrrk2 and Lrrk2 splice variants in mice.

Missense mutations in the leucine-rich repeat kinase 2 gene (LRRK2) are linked to autosomal dominant forms of Parkinson's disease (PD). In order to get insights into the physiological role of Lrrk2, we examined the distribution of Lrrk2 mRNA and different splice variants in the developing murine embryo and the adult brain of Mus musculus. To analyse if the Lrrk2-paralog, Lrrk1, may have redundant functions in PD-development, we also compared Lrrk1 and Lrrk2 expression in the same tissues. Using radioactive in situ hybridization, we found ubiquitous expression of both genes at low level from embryonic stage E9.5 onward, which progressively increased up until birth. The developing central nervous system (CNS) displayed no prominent Lrrk2 mRNA signals at these time-points. However, in the entire postnatal brain Lrrk2 became detectable, showing strongest level in the striatum and the cortex of adult mice; Lrrk1 was only detectable in the mitral cell layer of the olfactory bulb. Thus, due to the non-overlapping expression patterns, a redundant function of Lrrk2 and Lrrk1 in the pathogenesis of PD seems to be unlikely. Quantification of Lrrk2 mRNA and protein level in several brain regions by real-time PCR and Western blot verified the striatum and cortex as hotspots of postnatal Lrrk2 expression. Strong expression of Lrrk2 is mainly found in neurons, specifically in the dopamine receptor 1 (DRD1a) and 2 (DRD2)-positive subpopulations of the striatal medium spiny neurons. Finally, we identified 2 new splice-variants of Lrrk2 in RNA-samples from various adult brain regions and organs: a variant with a skipped exon 5 and a truncated variant terminating in an alternative exon 42a. In order to identify the origin of these two splice variants, we also analysed primary neural cultures independently and found cell-specific expression patterns for these variants in microglia and astrocytes.

Grip strength in healthy caucasian adults: reference values.

PURPOSE: The aim of this study was to update reference data of handgrip strength for healthy adults of both genders spanning a wide age range and to analyze possible factors of influence. METHODS: Intraindividual and interindividual variations of grip strength and their relation to several anthropometric factors were analyzed in a standardized manner for 769 healthy adults (women, n = 403; men, n = 366) aged between 20 years and 95 years. Measurements were done in neutral position of arm, forearm, and wrist on setting II of a Baseline digital hydraulic dynamometer (NexGen Ergonomics Inc. Quebec, Canada). RESULTS: Mean strength was about 41% less in women (right 29 kg; left 27 kg) than in men (right 49 kg; left 47 kg) resulting in a ratio of left to right hand slightly above .95 in both genders. During the course of life, hand strength develops comparably in both genders peaking at 35 years of age and decreasing continuously further on. Anthropometric variables such as forearm circumference and length, hand size, or body mass showed a positive correlation with grip strength. Body mass index, type of work, and hand dominance showed only a partial positive correlation or no correlation with grip strength. Gender and age, followed by parameters representing body length and obesity, were observed to have the highest predictive value for handgrip strength and were therefore entered into the generation of prediction equations. CONCLUSIONS: We recommend side adjustment of measured values for intraindividual comparison and inclusion of information regarding anthropometric characteristics, as well as using gender- and age-adjusted reference values, whereas hand dominance can be neglected. The regression equations we generated might prove to be useful for clinicians or for those who use normative values within software to provide more accurate predictions of strength scores for specific applications.

Forearm rotation in healthy adults of all ages and both sexes.

Factors such as sex, age, or hand dominance are supposed to influence forearm rotation; however, available data are scarce. This study therefore analyzed range of active supination and pronation bilaterally in 752 healthy white adults (age range, 20-95 years) of both sexes. Range of supination was higher than pronation. Range of forearm rotation was comparable between both sides, but it was higher in women than in men and inversely correlated with age. In contrast with women, where range started to decrease during the fifth decade of life, onset was later in men (seventh decade). No influence was observed with respect to hand dominance or constitutional variations. Thus, the contralateral side serves for clinical comparison independent from age, sex, hand dominance, or constitutional variances. The fact that several patients with a major limitation of pronation considered themselves healthy, but only 1 patient with limited supination did so, indirectly underlines the importance of restoring deficits of supination rather than pronation.

Tumor necrosis factor-alpha-dependent expression of phosphodiesterase 2: role in endothelial hyperpermeability.

The pleiotropic cytokine tumor necrosis factor-alpha (TNF-alpha) and thrombin lead to increased endothelial permeability in sepsis. Numerous studies demonstrated the significance of intracellular cyclic nucleotides for the maintenance of endothelial barrier function. Actions of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) are terminated by distinct cyclic nucleotide phosphodiesterases (PDEs). We hypothesized that TNF-alpha could regulate PDE activity in endothelial cells, thereby impairing endothelial barrier function. In cultured human umbilical vein endothelial cells (HUVECs), we found a dramatic increase of PDE2 activity following TNF-alpha stimulation, while PDE3 and PDE4 activities remained unchanged. Significant PDE activities other than PDE2, PDE3, and PDE4 were not detected. TNF-alpha increased PDE2 expression in a p38 mitogen-activated protein kinase (MAPK)-dependent manner. Endothelial barrier function was investigated in HUVECs and in isolated mice lungs. Selective PDE2 up-regulation sensitized HUVECs toward the permeability-increasing agent thrombin. In isolated mice lungs, we demonstrated that PDE2 inhibition was effective in preventing thrombin-induced lung edema, as shown with a reduction in both lung wet-to-dry ratio and albumin flux from the vascular to bronchoalveolar compartment. Our findings suggest that TNF-alpha-mediated up-regulation of PDE2 may destabilize endothelial barrier function in sepsis. Inhibition of PDE2 is therefore of potential therapeutic interest in sepsis and acute respiratory distress syndrome (ARDS).