PNMA family: Protein interaction network and cell signalling pathways implicated in cancer and apoptosis

Paraneoplastic Ma Family (PNMA) comprises a growing number of family members which share relatively conserved protein sequences encoded by the human genome and is localized to several human chromosomes, including the X-chromosome. Based on sequence analysis, PNMA family members share sequence homology to the Gag protein of LTR retrotransposon, and several family members with aberrant protein expressions have been reported to be closely associated with the human Paraneoplastic Disorder (PND). In addition, gene mutations of specific members of PNMA family are known to be associated with human mental retardation or 3-M syndrome consisting of restrictive post-natal growth or dwarfism, and development of skeletal abnormalities. Other than sequence homology, the physiological function of many members in this family remains unclear. However, several members of this family have been characterized, including cell signalling events mediated by these proteins that are associated with apoptosis, and cancer in different cell types. Furthermore, while certain PNMA family members show restricted gene expression in the human brain and testis, other PNMA family members exhibit broader gene expression or preferential and selective protein interaction profiles, suggesting functional divergence within the family. Functional analysis of some members of this family have identified protein domains that are required for subcellular localization, protein-protein interactions, and cell signalling events which are the focus of this review paper.

Advances in Autoimmune Epilepsy Associated with Antibodies, Their Potential Pathogenic Molecular Mechanisms, and Current Recommended Immunotherapies

In this comprehensive article, we present an overview of some most common autoimmune antibodies believed to be potentially pathogenic for autoimmune epilepsies and elaborate their pathogenic mode of action in molecular levels based on the existing knowledge. Findings of the studies of immunemodulatory treatments for epilepsy are also discussed, and guidelines for immunotherapy are sorted out. We aim to summarize the emerging understanding of different pathogenic mechanisms of autoantibodies and clinical immunotherapy regimens to open up therapeutic possibilities for future optimum therapy. We conclude that early diagnosis of autoimmune epilepsy is of great significance, as early immune treatments have useful disease-modifying effects on some epilepsies and can facilitate the recovery.

Anti-Ma2-encephalitis in a 2 year-old child: A newly diagnosed case and literature review

BACKGROUND

Anti-Ma2-associated encephalitis is a rare paraneoplastic neurological syndrome characterized by isolated or combined limbic, diencephalic, or brainstem dysfunction. It is rarely reported in children.

CASE STUDY

We describe the clinical data of a 2-year-old girl referred to our department for refractory focal seizures associated with fever, followed by behavioural changes, speech disturbances and confusional episodes. Brain magnetic resonance imaging (MRI) showed left temporoparietal brain involvement. Haematological, biochemical and infectious evaluations were unremarkable. Autoimmune encephalitis was suspected. Paraneoplastic antibodies tests showed positive results for anti-Ma2 antibodies. Screening for underlying tumour was negative. Immunomodulatory treatment was administrated. The patient showed improvement of vigilance and behaviour. However, she kept refractory epilepsy.

CONCLUSION

Although poor response to immunotherapy, early diagnosis and appropriate treatment of this disorder may prevent irreversible sequelae.

Cancer-associated retinopathy in a patient with seminoma

PURPOSE

The purpose of this study was to report our findings on a patient with cancer-associated retinopathy who had seminoma.

METHODS

A 43-year-old man, who had been diagnosed with Stage 1 seminoma, complained of blurred vision. Fundus examination revealed attenuated retinal arteries, mild optic disk pallor, and a thinning of the outer nuclear layer. Ring scotomas were found in the visual fields of both eyes. The amplitudes of the electroretinograms were moderately reduced. The patient's serum was analyzed for antibodies.

RESULTS

Antibodies against recoverin, Hu, and Ma-2 antigens were not detected. However, Western blots of the serum detected 2 bands at 41 and 64 kDa. The 41-kDa band was an anti-retina-specific antibody. Immunoreactivity was identified in the photoreceptor layer of mice retinas. From these findings, we diagnosed the patient with cancer-associated retinopathy. The visual functions remained stable after the removal of the primary lesion at an early stage, treatment with steroids, and intravenous immunoglobulin.

CONCLUSION

This is the first case of cancer-associated retinopathy because of seminoma. The progression of the disease was reduced by removing the seminoma at an early stage, treatment with steroids, and intravenous immunoglobulin.