Nitrosative-induced posttranslational α-tubulin changes on high-glucoseexposed Schwannoma cell line

OBJECTIVE: One of the major complications during prolonged hyperglycemic
condition is the onset of the so-called diabetic neuropathy, that can affect the
peripheral nervous system. Evidence has reported that glucose-induced oxidative
stress could be a key mediator in this process, impairing the cytoskeletal structures,
such as microtubules. In general, much attention is paid to the possible
nitrosative-induced changes of neurons during hyperglycemic conditions, while
little is known of the Schwann cells.
METHODS: Using morphological examination, immunofluorescence staining and
western blot analysis, the possible hyperglycemic oxidative-induced microtubular
changes in the RT4 Schwannoma cell line was investigated.
RESULTS: After 72 hrs of 180 mM d-glucose exposure, a decrease of total, tyrosinated
and detyrosinated α-tubulins was found, whereas a significant increase of
the acetylated α-tubulin isotype and 3-nitro-l-tyrosine was present, both through
western blot and immunofluorescence staining. Moreover a downregulation of
catalase and deacetylase Sirt2 enzymes was detected.
CONCLUSION: Our data underline the importance of nitrosative-induced microtubular
alterations in the PNS, during hyperglycemic conditions, highlighting that
Schwann cells may be directly involved in the pathogenesis of diabetic neuropathy,
through the impairment of their microtubular network.