Classification of Myopathies on Molecular basis in Drosophila using Raman spectroscopy

Classification of Myopathies on Molecular basis in Drosophila using Raman spectroscopy

Rekha Gautam¹, Sandeep Vanga¹, Aditi Madan², Upendra Nongthomba² and Siva Umapathy^1*

1Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India;

2Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012, India.

E-mail: umapathy@ipc.iisc.ernet.in

Myopathies are muscular diseases in which muscle fibers degenerate due to many factors such as mutations in myofibrillar and internal cytoskeletal proteins, infection, nutrient deficiency etc. The indirect flight muscles (IFM) of Drosophila melanogaster are physiologically similar to cardiac muscles and structurally similar to skeletal muscles of human and therefore provide an excellent system to investigate molecular changes due to various myopathies [1]. The objective of present study is to identify the bio-markers to distinguish various muscle mutants in Drosophila using Raman spectroscopy which provides a unique molecular fingerprint of tissues on the basis of their molecular composition [2]. Raman

spectra were collected from IFM of mutants upheld¹ (up¹), heldup² (hdp²), Myosin heavy chain⁷ (Mhc⁷), Actin88F^KM88 (Act88F^KM88), upheld¹⁰¹ (up¹⁰¹) and Canton-S (CS) flies. The difference spectra provide insight into the biochemical changes of the tissues that accompany mutations. Principal Components based Linear

Discriminant Analysis (PC-LDA) classification model was developed, which classifies the mutants according to their physiopathology and yielded overall accuracy (OA) of 97% and 93% for 2 and 12 days old flies respectively [2-3]. Notably, up¹ & Act88F^KM88 (nemaline myopathy) form a group which is clearly separated by a Linear Discriminant Function (LDF) from up¹⁰¹ & hdp² (cardiomyopathy). Here, we demonstrate that Raman spectroscopy study combined with multivariate analysis Drosophila model could be used to study the mechanism of various human disorders where biopsy is difficult.

Acknowledgement(s) This work was supported by financial assistance from Indian Institute of Science (IISc), Department of Biotechnology (DBT) and Department of Science and Technology (DST), Government of India..

References

[1] U. Nongthomba, M. Cummins, S. Clark, J. O. Vigoreaux, J. C. Sparrow, Genetics, 164(2003) 209–222.

[2] A. S. Haka AS et al., Proc Natl Acad Sci USA, 102(2005)12371–12376.

[3] A. M. Herrero, Critical Reviews in Food Science and Nutrition, 48(2008) 512–523.