Depletion of TMEM65 leads to oxidative stress,apoptosis, induction of mitochondrial unfolded protein response,and upregulation of mitochondrial protein import receptor TOMM22

Mutation in the transmembrane protein 65 gene (TMEM65) results in mitochondrial dysfunction and a severe mitochondrial encephalomyopathy phenotype. However, neither the function of TMEM65 nor the cellular responses to its depletion have been fully elucidated. Hence, we knocked down TMEM65 in human cultured cells and analyzed the resulting cellular responses. Depletion of TMEM65 led to a mild increase in ROS generation and upregulation of the mRNA levels of oxidative stress suppressors, such as NFE2L2 and SESN3, indicating that TMEM65 knockdown induced an oxidative stress response. A mild induction of apoptosis was also observed upon depletion of TMEM65. Depletion of TMEM65 upregulated protein levels of the mitochondrial chaperone HSPD1 and mitochondrial protease LONP1, indicating that mitochondrial unfolded protein response (UPR^mt) was induced in response to TMEM65 depletion. Additionally, we found that the mitochondrial protein import receptor TOMM22 and HSPA9 (mitochondrial Hsp70), were also upregulated in TMEM65-depleted cells. Notably, the depletion of TMEM65 did not lead to upregulation of TOMM22 in an ATF5-dependent manner, although upregulation of LONP1 reportedly occurs in an ATF5-dependent manner. Taken together, our findings suggest that depletion of TMEM65 causes mild oxidative stress and apoptosis, induces UPR^mt, and upregulates protein expression of mitochondrial protein import receptor TOMM22 in an ATF5-independent manner.     

Involvement of ERK1/2 activation in the gene expression of senescence-associated secretory factors in human hepatic stellate cells

Molecular and Cellular Biochemistry - Senescent hepatic stellate cells (senescent HSCs) are found in patients with liver cirrhosis and have been thought to be involved in the development of...     

L-proline-catalyzed enantioselective one-pot cross-Mannich reaction of aldehydes

This protocol describes a procedure for the synthesis of syn-beta-amino alpha-substituted aldehydes, versatile intermediates in synthetic organic chemistry, via asymmetric, direct, one-pot, three-component, cross-Mannich reaction of two different aldehydes. The reaction consists of two steps; one is the formation of imine by the reaction of aldehyde and p-anisidine in the presence of Pro, and the second step is the enantioselective addition reaction of enamine generated from the other aldehyde and Pro with the imine generated in the first step. As the aldehyde easily racemizes, gamma-amino alcohol was isolated and characterized after reduction. The yield and diastereo- and enantioselectivities are generally excellent. It will take approximately 26 h to complete the protocol: 0.5 h to set up the reaction, 20.5 h for the reaction and 5 h for the isolation and purification.     

Phylogenetic relationships of rodent pinworms (genus Syphacia) in Japan inferred from 28S rDNA sequences

The 28S rDNA from nine species of the genus Syphacia collected in Japan was sequenced, and the phylogenetic relationship was inferred from multiple sequence alignment of 28S rDNA by the MAFFT program. Phylogenetic tree indicates that S. petrusewiczi, which was the only species belonging to the subgenus Seuratoxyuris, has diverged earlier than other rodent pinworms examined and was distantly separated from the others genetically. It was revealed that S. agraria and S. vandenbrueli, whose subgeneric status has not been specified, belonged to the subgenus Syphacia together with other 6 species. Syphacia montana from Clethrionomys, Eothenomys and Microtus was very closely related to S. obvelata from Mus, and that S. frederici from Apodemus and S. vandenbrueli from Micromys were comparatively closely related to the former two species. The phylogenetic relationship among the three species of Syphacia found in Japanese Apodemus was inconsistent with the biogeography of host rodents. The co-evolutionary relationship between pinworm species and their host rodents may not be so strict and host switching has probably occurred frequently during the course of evolution.     

Analytical study of repair cells

To establish the differential diagnosis of repair cells from malignant cells, 624 repair cells from 11 cases, 547 cells derived from 8 adenocarcinomas and 593 cells from 8 squamous-cell carcinomas were analyzed, with stress on the morphology of the nucleoli. Such planimetric data as mean cellular areas, mean nuclear areas, mean nucleolar areas, nuclear-cytoplasmic ratios and nucleolar-nuclear ratios were fairly similar among the three cell groups. However, the even distribution of nucleoli in the nuclei, the decrease in C-type nucleoli and nucleoli consistently linked with nucleolus-associated chromatin were noted to be reliable criteria for the diagnosis of repair cells along with such well-known morphologic characteristics as the sheetlike arrangement of repair cells, the lack of isolated forms, the finely granular chromatin pattern and the round, smooth nuclear configuration with a thin nuclear membrane.