Hyperosmotic Stress Induces Aquaporin-dependent Cell Shrinkage, Polyphosphate Synthesis, Amino Acid Accumulation, and Global Gene Expression Changes in Trypanosoma cruzi

Abstract

Background: Trypanosoma cruzi is subjected to hyperosmotic stress during its life cycle. Results: The recovery from hyperosmotic stress involves the function of an aquaporin, amino acid accumulation, polyphosphate synthesis, and global gene regulation. Conclusion:The response to hyperosmotic stress is different from that observed in mammalian cells or yeasts. Significance: Learning the mechanism of osmoregulation is important for finding new drug targets.

Trypanosoma brucei Vacuolar Transporter Chaperone 4 (TbVtc4) Is an Acidocalcisome Polyphosphate Kinase Required for in Vivo Infection

“…Content-Previous studies demonstrated that polyP is important for trypanosome growth and osmoregulation in trypanosomes (22,23,27,30,31,37), but the length of the polyP responsible for these roles was not investigated. To investigate whether the short chain polyP synthesized by TbVtc4 is involved in these processes, we analyzed the phenotypic changes of BSF trypanosomes with a conditional KO of TbVtc4.…”

“…PolyP hydrolysis occurs during hyposmotic stress of trypanosomes (22), probably increasing the osmotic pressure of the acidocalcisomes and facilitating water movement. On the other hand, an increase in long chain polyP levels has been observed in T. cruzi during hyperosmotic stress (22,23). This latter work suggested that polyP could play an important role at the early stages of hyperosmotic stress response by sequestering ions into the acidocalcisomes to reduce the ionic strength of the cytosol (23).…”

“…Northern Blot Analysis-Northern blot analysis was performed as described previously (23). Briefly, total RNA was isolated from BSF using TRI Reagent.…”

“…This resistance to osmotic stress is essential for digenetic trypanosomatids as they encounter drastic osmotic changes in both the insect vectors and vertebrate hosts (23,25,26). Regulation of cell volume is, in addition, a homeostatic process needed at all times by all cells.…”

“…Previous work has shown that polyP has a critical role in survival of trypanosomes under sharp environmental changes, including osmotic stress (22)(23)(24). This resistance to osmotic stress is essential for digenetic trypanosomatids as they encounter drastic osmotic changes in both the insect vectors and vertebrate hosts (23,25,26).…”