Biology of the Cell最新文献

Background

The Endosomal Sorting Complex Required for Transport (ESCRT) is a highly conserved cellular machinery essential for many cellular functions, including transmembrane protein sorting, endosomal trafficking, and membrane scission. CHMP4B is a key component of ESCRT-III subcomplex and has been thoroughly studied in the meroistic ovaries of Drosophila melanogaster showing its relevance in maintaining this reproductive organ during the life of the fly. However, the role of the CHMP4B in the most basal panoistic ovaries remains elusive.

Results

Using RNAi, we examined the function of CHMP4B in the ovary of Blattella germanica in two different physiological stages: in last instar nymphs, with proliferative follicular cells, and in vitellogenic adults when follicular cells enter in polyploidy and endoreplication. In Chmp4b-depleted specimens, the actin fibers change their distribution, appearing accumulated in the basal pole of the follicular cells, resulting in an excess of actin bundles that surround the basal ovarian follicle and modifying their shape. Depletion of Chmp4b also determines an actin accumulation in follicular cell membranes, resulting in different cell morphologies and sizes. In the end, these changes disrupt the opening of intercellular spaces between the follicular cells (patency) impeding the incorporation of yolk proteins to the growing oocyte and resulting in female sterility. In addition, the nuclei of follicular cells appeared unusually elongated, suggesting an incomplete karyokinesis.

Conclusions

These results proved CHMP4B essential in preserving the proper expression of cytoskeleton proteins vital for basal ovarian follicle growth and maturation and for yolk protein incorporation. Moreover, the correct distribution of actin fibers in the basal ovarian follicle emerged as a critical factor for the successful completion of ovulation and oviposition.

Significance

The overall results, obtained in two different proliferative stages, suggest that the requirement of CHMP4B in B. germanica follicular epithelium is not related to the proliferative stage of the tissue.

Bacground Information

Lung cancer is one of the leading types of cancer deaths worldwide, with approximately 2 million people diagnosed with lung cancer each year. In this study, we aimed to determine the exonic and 3′UTR sequences of EGFR, PIK3CA and KRAS genes in 39 sporadic lung cancer tumors and to reveal the changes in the miRNA binding profile of tumors with somatic variation in the 3'UTR region and to examine the relationship of these changes with clinical parameters.

Results

A statistically significant correlation was found between the presence of miRNA that could not bind to the 3′UTR region due to variation in at least one of the EGFR or KRAS genes and the presence of metastasis in the tumor. At the same time, Kaplan-Meier analysis between those with and without alterations in the miRNA profile due to somatic variation in the 3′UTR region showed that survival was lower in those with miRNA alterations and this was statistically significant.

Conclusions

In our study, it was shown that variations in the 3′UTR regions of EGFR and KRAS oncogenes may cause increased expression of these oncogenes by preventing the binding of miRNAs, and it was suggested that this may be related to metastasis, survival and drug resistance mechanism.

Significance

In this study, we show that hsa-miR-124-3p, hsa-miR-506-3p, hsa-miR-1290 and hsa-miR-6514-3p are particularly prominent in lung carcinoma in relation to these biological pathways and the roles that variations in the 3′UTR regions of oncogenes may play in the carcinogenesis process.

Background Information

The control of epithelial cell polarity is key to their function. Its dysregulation is a major cause of tissue transformation. In polarized epithelial cells,the centrosome is off-centred toward the apical pole. This asymmetry determines the main orientation of the microtubule network and intra-cellular traffic. However, the mechanism regulating centrosome positioning at the apical pole of polarized epithelial cells is still poorly undertood.

Results

In this study we used transcriptomic data from breast cancer cells to identify molecular changes associated with the different stages of tumour transformation. We correlated these changes with variations in centrosome position or with cell progression along the epithelial-to-mesenchymal transition (EMT), a process that involves centrosome repositioning. We found that low levels of epiplakin, desmoplakin and periplakin correlated with centrosome mispositioning in cells that had progressed through EMT or tissue transformation. We further tested the causal role of these plakins in the regulation of centrosome position by knocking down their expression in a non-tumorigenic breast epithelial cell line (MCF10A). The downregulation of periplakin reduced the length of intercellular junction, which was not affected by the downregulation of epiplakin or desmoplakin. However, down-regulating any of them disrupted centrosome polarisation towards the junction without affecting microtubule stability.

Conclusions

Altogether, these results demonstrated that epiplakin, desmoplakin and periplakin are involved in the maintenance of the peripheral position of the centrosome close to inter-cellular junctions. They also revealed that these plakins are downregulated during EMT and breast cancer progression, which are both associated with centrosome mispositioning.

Significance

These results revealed that the down-regulation of plakins and the consequential centrosome mispositioning are key signatures of disorganised cytoskeleton networks, inter-cellular junction weakening, shape deregulation and the loss of polarity in breast cancer cells. These metrics could further be used as a new readouts for early phases of tumoral development.

Background

Red blood cells (RBCs) are usually considered simple cells and transporters of gases to tissues.

Hypothesis

However, recent research has suggested that RBCs may have diagnostic potential in major neurodegenerative disorders (NDDs).

Results

This review summarizes the current knowledge on changes in RBC in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and other NDDs. It discusses the deposition of neuronal proteins like amyloid-β, tau, and α-synuclein, polyamines, changes in the proteins of RBCs like band-3, membrane transporter proteins, heat shock proteins, oxidative stress biomarkers, and altered metabolic pathways in RBCs during neurodegeneration. It also highlights the comparison of RBC diagnostic markers to other in-market diagnoses and discusses the challenges in utilizing RBCs as diagnostic tools, such as the need for standardized protocols and further validation studies.

Significance statement

The evidence suggests that RBCs have diagnostic potential in neurodegenerative disorders, and this study can pave the foundation for further research which may lead to the development of novel diagnostic approaches and treatments.

Polycystic ovary syndrome or PCOS is an endocrine disorder in women of reproductive age. It is a diversified multi factorial disorder and diagnosis is very complicated because of its overlapping symptoms some of which are irregular menstrual cycle, acne in face, excess level of androgen (AE), insulin resistance, obesity, cardiovascular disease, mood disorder and type 2 diabetes (T2DM). PCOS may be caused by hormonal imbalance, genetic and epigenetic vulnerability, hypothalamic and ovarian troubles. PCOS is essentially hyperandrogenimia with oligo-anovulation. This review explains the abnormal regulation of autophagy related genes and proteins in different cells at various stages which leads to the genesis of PCOS. During nutrient starvation cells face stress condition, which it tries to overcome by activating its macroautophagy mechanism and by degrading the cytoplasmic material. This provides energy to the cell facilitating its survival. Downregulation of autophagy related genes in endometria has been observed in PCOS women. PCOS can be managed by maintaining proper lifestyle and medical treatment. Healthy meals and regular exercise can prevent the excessive weight and also reduce the PCOS complications. Medicines such as metformin, clomiphene, and the oral contraceptive pill can also balance the hormonal level. The imbalance in regulation of autophagy genes has been discussed with correlation to PCOS. The different management strategies for PCOS have also been summarized.

Background Information

Aquaporins are H₂O-permeable membrane protein pores. However, some aquaporins are also permeable to other substances such as CO₂. In higher plants, overexpression of such aquaporins has already led to an enhanced photosynthetic performance due to improved CO₂ mesophyll conductance. In this work, we investigated the effects of such aquaporins on unicellular photosynthetically active organisms, specifically cyanobacteria.

Results

Overexpression of aquaporins NtAQP1 or hAQP1 that might have a function to improve CO₂ membrane permeability lead to increased photosynthesis rates in the cyanobacterium Synechococcus sp. PCC7002 as concluded by the rate of evolved O₂. A shift in the Plastoquinone pool state of the cells supports our findings. Water permeable aquaporins without CO₂ permeability, such as NtPIP2;1, do not have this effect.

Conclusions and Significance

We conclude that also in single cell organisms like cyanobacteria, membrane CO₂ conductivity could be rate limiting and CO₂-porins reduce the respective membrane resistance. We could show that besides the tobacco aquaporin NtAQP1 also the human hAQP1 most likely functions as CO₂ diffusion facilitator in the photosynthesis assay.

Background

Spermatogenesis is a fundamental process crucial for male reproductive health and fertility. Exosomes, small membranous vesicles released by various cell types, have recently garnered attention for their role in intercellular communication.

Objective

This review aims to comprehensively explore the role of exosomes in regulating spermatogenesis, focusing on their involvement in testicular development and cell-to-cell communication.

Methods

A systematic examination of literature was conducted to gather relevant studies elucidating the biogenesis, composition, and functions of exosomes in the context of spermatogenesis.

Results

Exosomes play a pivotal role in orchestrating the complex signaling networks required for proper spermatogenesis. They facilitate the transfer of key regulatory molecules between different cell populations within the testes, including Sertoli cells, Leydig cells, and germ cells.

Conclusion

The emerging understanding of exosome-mediated communication sheds light on novel mechanisms underlying spermatogenesis regulation. Further research in this area holds promise for insights into male reproductive health and potential therapeutic interventions.