Histology and histopathology Vol.26,nº11 (2011)

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Open Access
Novel therapeutic strategies to target RCAS1, which induces apoptosis via ectodomain shedding
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Sonoda, Kenzo
The expression of receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is associated with aggressive characteristics and poor overall survival for 15 different human malignancies. The correlation between RCAS1 expression and several clinicopathological variables, including tumor size, clinical stage, invasion depth and lymph node metastasis highlights this molecule’s clinical significance. RCAS1 is a biomarker because: (1) its concentration in serum or pleural effusion is significantly higher in cancer patients; (2) its level is associated with treatment response; and (3) high RCAS1-valued serum from cancer patients inhibits growth of RCAS1 putative receptor-expressing K562 cells. RCAS1 is secreted by ectodomain shedding and induces apoptosis in peripheral lymphocytes and natural killer (NK) cells. Although its putative receptor and mechanism of apoptosis induction remain undefined, RCAS1 is believed to help tumor cells evade immune surveillance. RCAS1 expression is also related to changes in extracellular matrix characteristics, reduction of vimentin-positive stromal cells, and increased microvessel density (MVD), all suggesting that RCAS1 may induce connective tissue remodeling. Further exploration of RCAS1 biological function will facilitate development of novel therapeutic strategies that target RCAS1.
Open Access
Polarity proteins and actin regulatory proteins are unlikely partners that regulate cell adhesion in the seminiferous epithelium during spermatogenesis
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Cheng, C. Yan; Wong, Elissa W.P.; Lie, Pearl P.Y.; Mruk, Dolores D.; Xiao, Xiang; Li, Michelle W.M.; Lui, Wing-Yee; Lee, Will M.
In mammalian testis, spermatogenesis takes place in the seminiferous epithelium of the seminiferous tubule, which is composed of a series of cellular events. These include: (i) spermatogonial stem cell (SSC) renewal via mitosis and differentiation of SSC to spermatogenia, (ii) meiosis, (iii) spermiogenesis, and (iv) spermiation. Throughout these events, developing germ cells remain adhered to the Sertoli cell in the seminiferous epithelium amidst extensive cellular, biochemical, molecular and morphological changes to obtain structural support and nourishment. These events are coordinated via signal transduction at the cell-cell interface through cell junctions, illustrating the significance of cell junctions and adhesion in spermatogenesis. Additionally, developing germ cells migrate progressively across the seminiferous epithelium from the stem cell niche, which is located in the basal compartment near the basement membrane of the tunica propria adjacent to the interstitium. Recent studies have shown that some apparently unrelated proteins, such as polarity proteins and actin regulatory proteins, are in fact working in concert and synergistically to coordinate the continuous cyclic changes of adhesion at the Sertoli-Sertoli and Sertoli-germ cell interface in the seminiferous epithelium during the epithelial cycle of spermatogenesis, such that developing germ cells remain attached to the Sertoli cell in the epithelium while they alter in cell shape and migrate across the epithelium. In this review, we highlight the physiological significance of endocytic vesicle-mediated protein trafficking events under the influence of polarity and actin regulatory proteins in conferring cyclic events of cell adhesion and de-adhesion. Furthermore, these recent findings have unraveled some unexpected molecules to be targeted for male contraceptive development, which are also targets of toxicant-induced male reproductive dysfunction.
Open Access
Potential role of chitinases and chitin-binding proteins in host-microbial interactions during the development of intestinal inflammation
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Tran, Hoa T.; Barnich, Nicolas; Mizoguchi, Emiko
The small and large intestines contain an abundance of luminal antigens derived from food products and enteric microorganisms. The function of intestinal epithelial cells is tightly regulated by several factors produced by enteric bacteria and the epithelial cells themselves. Epithelial cells actively participate in regulating the homeostasis of intestine, and failure of this function leads to abnormal and host-microbial interactions resulting in the development of intestinal inflammation. Major determinants of host susceptibility against luminal commensal bacteria include genes regulating mucosal immune responses, intestinal barrier function and microbial defense. Of note, it has been postulated that commensal bacterial adhesion and invasion on/into host cells may be strongly involved in the pathogenesis of inflammatory bowel disease (IBD). During the intestinal inflammation, the composition of the commensal flora is altered, with increased population of aggressive and detrimental bacteria and decreased populations of protective bacteria. In fact, some pathogenic bacteria, including Adherent-Invasive Escherichia coli, Listeria monocytogenes and Vibrio cholerae are likely to initiate their adhesion to the host cells by expressing accessory molecules such as chitinases and/or chitin-binding proteins on themselves. In addition, several inducible molecules (e.g., chitinase 3-like 1, CEACAM6) are also induced on the host cells (e.g. epithelial cells, lamina proprial macrophages) under inflammatory conditions, and are actively participated in the host-microbial interactions. In this review, we will summarize and discuss the potential roles of these important molecules during the development of acute and chronic inflammatory conditions.
Open Access
Alterations of the perivascular dystrophin-dystroglycan complex following brain lesions. An immunohistochemical study in rats
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Kálmán, Mihály; Mahalek, J.; Adorján, A.; Pócsai, Károly; Bagyura, Zsolt; Sadeghian, S.
Dystroglycan is a laminin receptor, which with dystrophins and other components forms the dystrophin-dystroglycan complex. It has an important role in the formation of gliovascular connections, cerebral vascularisation and blood-brain barrier. Dystroglycan consists of two sub-units, α and ß. Previous studies demonstrated that the ß-dystroglycan immunoreactivity of cerebral vessels temporarily disappeared in the area adjacent to the lesion, whereas the vascular laminin which is not immunoreactive in the intact brain became detectable. The present study extends these investigations over other components of the complex: utrophin, α1-syntrophin and α1-dystrobrevin. The experiments were performed on adult rats. The lesions were stab wounds or cryogenic lesions in deep ketamine-xylasine narcosis. Following survival periods 2 to 30 days, the animals were perfused and floating brain sections were processed for fluorescent immunohistochemistry. The α1-dystrobrevin, like ß-dystroglycan, vanished temporarily around the lesion. The immunoreactivity of utrophin changed in a similar way to that of laminin. In intact brains they were confined to the entering segments of the vessels and to the circumventricular organs. Following lesions their immunoreactivity manifested in the vessels around the lesions. However, utrophin followed laminin with a delay: their peaks were about POD (postoperative days) 21 and 7, respectively. Only immunoreactivity of α1-syntrophin appeared in the reactive astrocytes, peaking at POD 14. Double-labeling proved its co-localization with GFAP. Cryogenic lesions had similar immunohistochemical effects, but provided more suitable samples for Western blot analysis, which proved the altered levels of α1-dystrobrevin and α1-syntrophin. The phenomena may help to monitor the post-lesion vascular processes and the alterations of the gliovascular connections.
Open Access
Nuclear relocation of DGKζ in cardiomyocytes under conditions of ischemia/reperfusion
(F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Akiyama, Hideyuki; Hozumi, Yasukazu; Nakano, Tomoyuki; Kubota, Isao; Goto, Kaoru
Diacylglycerol (DG) and phosphatidic acid (PA) are generated under various conditions, such as ligand stimulation and several stresses. They serve as second messengers to respond to pathophysiological conditions. DG kinase (DGK) catalyzes DG to produce PA. It is regarded as a regulator of these lipid messengers. Previous studies show that DGKζ, a nuclear isozyme, translocates from the nucleus to the cytoplasm in hippocampal neurons under transient ischemia and never relocates to the nucleus after reperfusion. This study examined whether a similar phenomenon is observed in cardiomyocytes, which represent another type of postmitotic, terminally differentiated cell. We performed immunostaining on ischemic hearts induced by occlusion of the left anterior descending coronary artery and on primary cultured cardiomyocytes under oxygen-glucose deprivation (OGD). In the animal model, 10 min ischemia is sufficient to cause DGKζ to disappear from the nucleus in cardiomyocytes. However, DGKζ is observed again in the nucleus at 10 min following reperfusion after 10 min ischemia, which contrasts sharply with ischemic hippocampal neurons. Similar results were obtained from experiments using primary cultured cardiomyocytes under OGD conditions, except that DGKζ relocates autonomously, if at all, to the nucleus, even under continuous OGD conditions. Results suggest that DGKζ is involved in the acute phase of cellular response to ischemic stress in cardiomyocytes in a similar, but not identical, manner to that of neurons.

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