👤 Manning Qian

The intense inhomogeneous magnetic fields acting on the diamagnetic materials naturally present in cells can generate strong magnetic forces. We have developed a superconducting magnet platform with large gradient high magnetic field (LG-HMF), which can produce three magnetic force fields of -1360, 0, and 1312 T(2)/m, and three corresponding apparent gravity levels, namely 0, 1, and 2-g for diamagnetic materials. In this study, the effects of different magnetic force fields on osteoblast-like cells (MG-63 and MC3T3-E1) viability, microtubule actin crosslinking factor 1 (MACF1) expression and its association with cytoskeleton were investigated. Results showed that cell viability increased to different degrees after exposure to 0 or 1-g conditions for 24 h, but it decreased by about 30% under 2-g conditions compared with control conditions. An increase in MACF1 expression at the RNA or protein level was observed in osteoblast-like cells under the magnetic force field of -1360 T(2)/m (0-g) relative to 1312 T(2)/m (2-g). Under control conditions, anti-MACF1 staining was scattered in the cytoplasm and partially colocalized with actin filaments (AFs) or microtubules (MTs) in the majority of osteoblast-like cells. Under 0-g conditions, MACF1 labeling was concentrated at perinuclear region and colocalization was not apparent. The patterns of anti-MACF1 labeling on MTs varied with MTs' changing under LG-HMF environment. In conclusion, LG-HMF affects osteoblast-like cell viability, MACF1 distribution, expression, and its association with cytoskeleton to some extent. Show less

During development, the proximal and distal regions of respiratory tract undergo distinct processes that ultimately give rise to conducting airways and alveoli. To gain insights into the genetic pathways differentially activated in these regions when branching morphogenesis is initiating, we characterized their transcriptional profiles in murine rudiments isolated at embryonic (E) day 11.5. By using oligonucleotide microarrays, we identified 83 and 128 genes preferentially expressed in branching and non-branching regions, respectively. The majority of these genes (85%) had not been previously described in the lung, or in other organs. We report restricted expression patterns of 22 of these genes were by in situ hybridization. Among them in the lung potential components of the Wnt, TGF beta, FGF and retinoid pathways identified in other systems, and uncharacterized genes, such as translocases, small GTPases and splicing factors. In addition, we provide a more detailed analysis of the expression pattern and regulation of a representative gene from the distal (transforming growth factor, beta induced) and proximal (WW domain-containing protein 2) regions. Our data suggest that these genes may regulate focal developmental events specific of each of these regions during respiratory tract formation. Show less

Activation of Wnt signaling through beta-catenin mutations contributes to the development of hepatocellular carcinoma (HCC) and hepatoblastoma (HB). To explore the contribution of additional Wnt pathway molecules to hepatocarcinogenesis, we examined beta-catenin, AXIN1 and AXIN2 mutations in 73 HCCs and 27 HBs. beta-catenin mutations were detected in 19.2% (14 out of 73) HCCs and 70.4% (19 out of 27) HBs. beta-catenin mutations in HCCs were primarily point mutations, whereas more than half of the HBs had deletions. AXIN1 mutations occurred in seven (9.6%) HCCs and two (7.4%) HBs. The AXIN1 mutations included seven missense mutations, a 1 bp deletion, and a 12 bp insertion. The predominance of missense mutations found in the AXIN1 gene is different from the small deletions or nonsense mutations described previously. Loss of heterozygosity at the AXIN1 locus was present in four of five informative HCCs with AXIN1 mutations, suggesting a tumor suppressor function of this gene. AXIN2 mutations were found in two (2.7%) HCCs but not in HBs. Two HCCs had both AXIN1 and beta-catenin mutations, and one HCC had both AXIN2 and beta-catenin mutations. About half the HCCs with AXIN1 or AXIN2 mutations showed beta-catenin accumulation in the nucleus, cytoplasm or membrane. Overall, these data indicate that besides the approximately 20% of HCCs and 80% of HBs with beta-catenin mutations contributing to hepatocarcinogenesis, AXIN1 and AXIN2 mutations appear to be important in an additional 10% of HCCs and HBs. Show less

Juvenile neuronal ceroid lipofuscinosis or Batten disease (JNCL) is a neurodegenerative disorder characterized by blindness, seizures, cognitive decline and early death. Brain atrophy and retinitis pigmentosa ensue because of neuronal and photoreceptor apoptosis. The CLN3 gene defective in JNCL encodes a novel 438 amino acid protein. Most affected genes harbor a deletion resulting in a truncated protein. CLN3 overexpression in NT2 cells enhances growth, reverses growth inhibition induced by serum starvation and protects from apoptosis induced by vincristine, staurosporine, and etoposide but not from death caused by ceramide. CLN3 modulates endogenous and vincristine-activated ceramide, and therefore suppresses apoptosis by impacting generation of ceramide. Show less

The late infantile and juvenile variants of Batten disease are genetically distinct neurodegenerative disorders. Hallmarks of Batten disease include cognitive and motor decline, seizures and blindness due to retinitis pigmentosa. Recently, the CLN3 gene responsible for the juvenile variant has been cloned. Also, apoptosis was proven to be the mechanism by which neurons and photoreceptors die. This paper provides mechanistic support for the occurrence of apoptosis in this disease: There was marked upregulation of Bcl-2 in brain from the late infantile and juvenile types at the protein and RNA levels both by immunocytochemistry and by Northern blot analysis; there were also a 42% to 197% increase in brain ceramide determinations in brains from three patients with the juvenile type and three patients with the late infantile type. Double immunolabeling of brain sections for apoptosis and Bcl-2 supported a protective role for Bcl-2 in the juvenile form of Batten disease. These results raise the possibility that the intact CLN3 gene is normally antiapoptotic, and that it could be an upstream regulator of ceramide. Show less