Differential degradation of RNA species by autophagy related pathways in plants

An important function of the plant vacuole is the recycling of the delivered proteins and RNA by autophagy. We provide the first plant vacuolar small RNome by isolation of intact vacuoles from Barley and Arabidopsis, subsequent RNA purification and Next Generation Sequencing. In these vacuolar sRNomes, all types of cellular RNAs were found including those of chloroplast origin, suggesting a bulk-type of RNA transfer to, and breakdown in vacuoles. ATG5 is a major representative of autophagy genes and the vacuolar RNA composition in corresponding knockout plants differed clearly from controls as most chloroplast derived RNA species were missing. Moreover, the read length distribution of RNAs found in ATG5 mutants differed to control samples, indicating altered RNA processing. In contrast, vacuolar RNA length and composition of plants lacking the vacuolar RNase2 (rns2-2), involved in cellular RNA homeostasis, showed minor alterations, only. Our data therefore suggests that mainly autophagy components are responsible for selective transport and targeting of different RNA species into the vacuole for degradation. In addition, mature miRNAs were detected in all vacuolar preparations, however in ATG5 mutants at much lower frequency, indicating a new biological role for vacuolar miRNAs apart from becoming degraded.

Protein carbonylation in freshly diagnosed hypothyroidism is independent of thyrotropin levels

BackgroundHypothyroidism is a common endocrine disorder with female preponderance. Protein carbonyls (cP) and malondialdehyde (MDA) are generated due to protein and lipid peroxidation, respectively. Oxidative stress (OS) in freshly diagnosed hypothyroidism met with conflicting data in the research. And, a clear relationship between OS and early hypothyroidism is very limited and obscure. Therefore, we aimed to investigate the association between levels of MDA vs. thyrotropin (TSH) and cP vs. TSH among freshly diagnosed hypothyroid subjects.MethodsWe collected blood samples of 80 hypothyroid subjects prior to initiation of thyroxine therapy to know the association between OS and freshly diagnosed hypothyroidism. Serum MDA, cP along with total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and triacylglycerols (TG) were quantified in patients as well as 80 age- and sex-matched control subjects.ResultsLevels of MDA and cP were significantly elevated among hypothyroid subjects as compared to control. The rise in MDA levels positively correlated with TSH values among the patients. In addition, cP levels were substantially elevated as compared to MDA values; however, it does not correlate with TSH among hypothyroid subjects.ConclusionsOur study found no relationship between cP and TSH in freshly diagnosed hypothyroidism. Though it may be due to differential degradation of protein peroxidation products, the mechanism needs further elucidation in future studies.