Compartmentalized ciliation changes of oligodendrocytes in aged mouse optic nerve

Primary cilia are microtubule-based sensory organelles that project from the apical surface of most mammalian cells, including oligodendrocytes, which are myelinating cells of the central nervous system (CNS) that support critical axonal function. Dysfunction of CNS glia is associated with aging-related white matter diseases and neurodegeneration, and ciliopathies are known to affect CNS white matter. To investigate age-related changes in ciliary profile, we examined ciliary length and frequency in the retinogeniculate pathway, a white matter tract commonly affected by diseases of aging but in which expression of cilia has not been characterized. We found expression of Arl13b, a marker of primary cilia, in a small group of Olig2-positive oligodendrocytes in the optic nerve, optic chiasm, and optic tract in young and aged C57BL/6 wild-type mice. While the ciliary length and ciliated oligodendrocyte cells were constant in young mice in the retinogeniculate pathway, there was a significant increase in ciliary length in the anterior optic nerve as compared to the aged animals. Morphometric analysis confirmed a specific increase in the ciliation rate of CC1⁺/Olig2⁺ oligodendrocytes in aged mice compared with young mice. Thus, the prevalence of primary cilia in oligodendrocytes in the visual pathway and the age-related changes in ciliation suggest that they may play important roles in white matter and age-associated optic neuropathies.     

CDKN2A-p53 mediated antitumor effect of Lupeol in head and neck cancer

Purpose

The tumor suppressor protein p53 is known to control cell cycle arrest and apoptosis. Lupeol is a phytochemical that has been found to induce apoptosis in different cancer types through the extrinsic pathway. As yet, however, its role in the induction of cell cycle arrest and apoptosis through the intrinsic pathway in head and neck cancer has not been investigated. Here, we aimed at understanding the mechanism underlying the antitumor effect of Lupeol in head and neck cancer.

Methods

The antitumor effect of Lupeol on oral and laryngeal carcinomas was assessed using two in vitro 2D cell line models (HEp-2, UPCI:SCC-131) and, subsequently, an ex vivo 3D tumor explant culture platform that maintains key features of the native tumor microenvironment. The mechanism underlying Lupeol-mediated antitumor responses was delineated using MTT, colony formation, flow cytometry, immunofluorescence, Western blotting and immunohistochemistry assays.

Results

We found that Lupeol induced an enhanced expression of p53 in both cell line models tested and, subsequently, cell cycle arrest at the G1 phase. In addition we found that, following Lupeol treatment, p53 induced Bax expression and activated the intrinsic apoptotic pathway (as measured by Caspase-3 cleavage). Interestingly, Lupeol was also found to trigger G1 cell cycle arrest through up-regulation of the expression of CDKN2A, but not p21, resulting in inhibition of CyclinD1. In an ex vivo platform Lupeol was found to impart a potent antitumor response as defined by inhibition of Ki67 expression, decreased cell viability and concomitant activation (cleavage) of Caspase-3. Finally, we found that Lupeol can re-sensitize primary head and neck squamous cell carcinoma (HNSCC) tumor samples that had clinically progressed under a Cisplatin treatment regimen.

Conclusion

Together, our data indicate that Lupeol may orchestrate a bifurcated regulation of neoplastic growth and apoptosis in head and neck cancers and may serve as a promising agent for the management of tumors that have progressed on a platinum-based treatment regimen.

     

Improved, atraumatic access to digits with severe flexor contractures: surgical tape and suture modification of the lead hand

We present a modification to the widely used lead hand retraction system that allows for improved surgical access to a digit with a severe flexor contracture. A simple construct using surgical adhesive tape and a silk suture can be made and applied to the digit and lead hand. Our technique is simple and inexpensive to use, and we recommend its use to improve surgical access without causing unnecessary trauma to the digit.