Doxorubicin-induced F-actin reorganization in cofilin-1 (nonmuscle) down-regulated CHO AA8 cells.

The actin cytoskeleton plays an important role in many cellular processes, including cell mortality, mitosis, cytokinesis, intracellular transport, endocytosis and secretion but also is involved in gene transcription. The dynamics of the actin cytoskeleton is controlled by different classes of actin-binding proteins (ABPs) which regulate the polymerization of actin filaments. In this report we used siRNA against cofilin-1 (nonmuscle) to demonstrate the effect of cofilin on the nuclear and cytoplasmic actin pools in CHO AA8 cells after exposition to various concentrations of doxorubicin. The immunofluorescence studies showed doxorubicin dose dependent tendency to formation the multinucleated giant cells, but also the increase of fluorescence intensity of cofilin in nuclei of untransfected cells. Induction of cell death with doxorubicin treatment in untransfected cells revealed both mitotic catastrophe (in both lower and higher doxorubicin doses) and apoptosis (mostly in higher doxorubicin doses), whereas among cofilin-1 down-regulated cells we observed only mitotic catastrophe. The results suggest that cofilin has apoptosis-inducing ability and that mitotic catastrophe is independent from F-actin content in cell nucleus. In this point of view we conclude that different mechanisms of chromatin reorganization are involved in these two processes. Moreover, we suppose that apoptosis and mitotic catastrophe are independent from each other

Electron microscope study of the advanced tendinopathy process of the long head of the biceps brachii tendon treated arthroscopically

Background: The ultrastructural alterations related to tendinopathy have not been well described. Most studies on this subject have been conducted many years ago and focused on material from the Achilles tendon. It was demonstrated that various comorbidities can affect ultrastructural alterations in the advanced tendinopathy; however, there is very little data on ultrastructural morphology in tendinopathies related to mechanical overload as in case of the long head of the biceps brachii tendon (LHBT). The aim was to determine intermediate ultrastructural alterations in middle to severe grade the LHBT tendinopathy and to establish if they are different than those reported in the literature for other anatomical locations. Materials and methods: In this study we examined the ultrastructure of a series of the LHBT fragments arthroscopically removed due to tendinopathy and inve­stigated the morphology of tenocytes and collagen fibres in cases of the LHBT tendinopathy. Results: In pathological samples tenocytes were randomly scattered, their shape was round and the shape of nuclei was also disrupted. The presence of apoptotic­-like features in tenocytes’ nuclei was noted. All samples showed replacement of collagen fibrils by non-collagen extracellular matrix and diffuse collagen disorganisation. Conclusions: It was demonstrated at ultrastructural level that the LHBT tendino­pathy is not simply a wear and tear phenomenon, since chronic degeneration of the extracellular matrix and tenocytes were present, similarly as in tendinopathies, in other anatomical locations. (Folia Morphol 2018; 77, 2: 371–377

Current concepts on the morphology of popliteus tendon and its clinical implications

In this review we described the anatomy and biomechanics of popliteus muscle and its tendon. Furthermore, we combined the anatomy with clinics and discussed a wide spectrum of disorders regarding the popliteus and its musculotendinous complex. There are three main anatomical regions of the popliteus musculotendinous complex: the proximal origin, the mid-portion, the distal part on the tibia. The unique localisation and various origins of the tendon, connected with structures such as fibular head, Wrisberg, Humphrey and posterior cruciate ligament, lateral meniscus, medial collateral ligament, give an implication to diagnosis and treatment. Popliteus dysfunction is often overlooked, that is the reason why diagnosis and treatment of its injuries is mostly insufficient. Repetitive or acute direct varus forces, when the tibia is in external rotation, and knee hyperextension or flexion with forced external rotation of the tibia, are the main mechanisms of trauma. Popliteus injuries mainly affect the athletic population and lead to severe activity limitations. Chronic disorders of the popliteus tendon, less known, are often described as tendinopathy and are frequently seen in runners. Their symptoms can mimic the lateral meniscal tears. On the other hand, high-energy traumatic injuries of the popliteus tendon often accompany complex, multi ligamentous injuries seen in competitive sports. We also presented the implication of popliteus tendon in knee arthroplasty, due to its particular exposition to iatrogenic trauma during surgery. The issues such as proper tibial component location and well-designed cut systems are crucial to avoid the popliteus impingement and preserve its structure

Possible import routes of proteins into the cyanobacterial endosymbionts/plastids of Paulinella chromatophora

The rhizarian amoeba Paulinella chromatophora harbors two photosynthetically active and deeply integrated cyanobacterial endosymbionts acquired ~60 million years ago. Recent genomic analyses of P. chromatophora have revealed the loss of many essential genes from the endosymbiont’s genome, and have identified more than 30 genes that have been transferred to the host cell’s nucleus through endosymbiotic gene transfer (EGT). This indicates that, similar to classical primary plastids, Paulinella endosymbionts have evolved a transport system to import their nuclear-encoded proteins. To deduce how these proteins are transported, we searched for potential targeting signals in genes for 10 EGT-derived proteins. Our analyses indicate that five proteins carry potential signal peptides, implying they are targeted via the host endomembrane system. One sequence encodes a mitochondrial-like transit peptide, which suggests an import pathway involving a channel protein residing in the outer membrane of the endosymbiont. No N-terminal targeting signals were identified in the four other genes, but their encoded proteins could utilize non-classical targeting signals contained internally or in C-terminal regions. Several amino acids more often found in the Paulinella EGT-derived proteins than in their ancestral set (proteins still encoded in the endosymbiont genome) could constitute such signals. Characteristic features of the EGT-derived proteins are low molecular weight and nearly neutral charge, which both could be adaptations to enhance passage through the peptidoglycan wall present in the intermembrane space of the endosymbiont’s envelope. Our results suggest that Paulinella endosymbionts/plastids have evolved several different import routes, as has been shown in classical primary plastids

Diversity of muskox Ovibos moschatus (Zimmerman, 1780) (Bovidae, Mammalia) in time and space based on cranial morphometry

Muskox Ovibos moschatus is a Pleistocene relic, which has survived only in North America and Greenland. During the Pleistocene, it was widely distributed in Eurasia and North America. To evaluate its morphological variability through time and space, we conducted an extensive morphometric study of 217 Praeovibos and Ovibos skull remains. The analyses showed that the skulls grew progressively wider from Praeovibos sp. to the Pleistocene O. moschatus, while from the Pleistocene to the recent O. moschatus, the facial regions of the skull turned narrower and shorter. We also noticed significant geographic differences between the various Pleistocene Ovibos crania. Siberian skulls were usually larger than those from Western and Central Europe. Eastern Europeanmuskoxen also exceeded in size those from the other regions of Europe. The large size of Late Pleistocene muskoxen from regions located in more continental climatic regimes was probably associated with the presence of more suitable food resources in steppe-tundra settings. Consistently, radiocarbon-dated records of this species are more numerous in colder periods, when the steppe-tundra was widely spread, and less abundant in warmer periods

The effect of piperlongumine on endothelial and lung adenocarcinoma cells with regulated expression of profilin-1

Maciej Gagat,1 Marta Hałas-Wiśniewska,1 Wioletta Zielińska,1 Magdalena Izdebska,1 Dariusz Grzanka,2 Alina Grzanka1 1Department of Histology and Embryology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland; 2Department of Clinical Pathomorphology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland Purpose: The aim of the study was to evaluate the effect of piperlongumine (2 and 4 µM) on endothelial EA.hy926 and lung adenocarcinoma A549 cells with regulated expression of profilin-1 (PFN1). Material and methods: The cytotoxicity of alkaloid was evaluated by MTT assay, while cell death was assessed using double staining with annexin V and propidium iodide. Subsequently, the level of PFN1 1) upregulation in EA.hy926 endothelial cells and 2) downregulation in A549 lung adenocarcinoma cells. The next step was the analysis of the effect of PFN1 manipulation on cytoskeletal proteins. Results: The results showed that piperlongumine may inhibit proliferation of EA.hy926 and A549 cell lines and also induce cell death in a dose-dependent manner. Furthermore, endothelial cells with PFN1 overexpression showed lower sensitivity to alkaloid and strengthening of cell–cell interactions. In the case of A549 cells, loss of PFN1 expression resulted in a lower percentage of early apoptotic cells, reorganization of F-actin and vimentin network, and reduction of migratory potential. Conclusion: We suggest that upregulation of PFN1 in endothelial cell line may stabilize the cell junctions. In turn, PFN1 downregulation in A549 cells probably suppresses cell migration and sensitizes cells to anticancer agents. Keywords: profilin-1, piperlongumine, lung cancer, endothelial cell, F-actin, lung adeno­carcinom

Doxorubicin-induced F-actin reorganization in cofilin-1 (nonmuscle) down-regulated CHO AA8 cells.

The actin cytoskeleton plays an important role in many cellular processes, including cell mortality, mitosis, cytokinesis, intracellular transport, endocytosis and secretion but also is involved in gene transcription. The dynamics of the actin cytoskeleton is controlled by different classes of actin-binding proteins (ABPs) which regulate the polymerization of actin filaments. In this report we used siRNA against cofilin-1 (nonmuscle) to demonstrate the effect of cofilin on the nuclear and cytoplasmic actin pools in CHO AA8 cells after exposition to various concentrations of doxorubicin. The immunofluorescence studies showed doxorubicin dose dependent tendency to formation the multinucleated giant cells, but also the increase of fluorescence intensity of cofilin in nuclei of untransfected cells. Induction of cell death with doxorubicin treatment in untransfected cells revealed both mitotic catastrophe (in both lower and higher doxorubicin doses) and apoptosis (mostly in higher doxorubicin doses), whereas among cofilin-1 down-regulated cells we observed only mitotic catastrophe. The results suggest that cofilin has apoptosis-inducing ability and that mitotic catastrophe is independent from F-actin content in cell nucleus. In this point of view we conclude that different mechanisms of chromatin reorganization are involved in these two processes. Moreover, we suppose that apoptosis and mitotic catastrophe are independent from each other