Modulation of the Host Nuclear Compartment by Trypanosoma cruzi Uncovers Effects on Host Transcription and Splicing Machinery

Abstract

Host manipulation is a common strategy for invading pathogens. Trypanosoma cruzi, the causative agent of Chagas Disease, lives intracellularly within host cells. During infection, parasite-associated modifications occur to the host cell metabolism and morphology. However, little is known about the effect of T. cruzi infection on the host cell nucleus and nuclear functionality. Here, we show that T. cruzi can modulate host transcription and splicing machinery in non-professional phagocytic cells during infection. We found that T. cruzi regulates host RNA polymerase II (RNAPII) in a time-dependent manner, resulting in a drastic decrease in RNAPII activity. Furthermore, host cell ribonucleoproteins associated with mRNA transcription (hnRNPA1 and AB2) are downregulated concurrently. We reasoned that T. cruzi may hijack the host U2AF35 auxiliary factor, a key regulator for RNA processing, as a strategy to affect the splicing machinery activities directly. In support of our hypothesis, we carried out in vivo splicing assays using an adenovirus E1A pre-mRNA splicing reporter, showing that intracellular T. cruzi directly modulates the host cells by appropriating U2AF35. For the first time, our results provide evidence of a complex and intimate molecular relationship between T. cruzi and the host cell nucleus during infection.

Trypanosoma cruzi infection induces DNA double-strand breaks and activates DNA damage response pathway in host epithelial cells

“…Here, we observed similar behaviour with parasites in close proximity to the host cell nucleus, suggesting a potential source of DNA injuries causing DNA breaks in the host. This event could be advantageous for parasite pathogenesis since DNA damage in infected cells could lead to regulation or interference in the host gene expression and transcription, as already seen in other studies 10 , 12 , 17 , 18 , 40 , 73 , 74 .…”

“…Pathogens manipulate their host cell environment to ensure their survival, such as altering transcription 18 , 61 , 62 , translation 63 , metabolic and signalling pathways 64 , 65 , and inducing morphological modifications 13 , 14 , 66 , 67 . Pathogens can also directly or indirectly affect the host cell by inducing changes to the host cell DNA 30 , 31 by the activation of the phosphoproteins H2AX, 53BP1, and ATM during the initial phase of the infection 21 , 23 , 26 , 68 .…”

“…Our recent work demonstrated at the beginning of the infection, the parasite is closely associated with the host cell nucleus, causing a nuclear deformation, promoting RNA Pol II pausing in the host, altering host splicing, and sequestering a host spliceosome protein 18 . It is well known that nuclear deformation could affect chromatin organization, correlating with DNA breaks 72 .…”

“…It has been reported that RNA Pol II can be rapidly blocked or degraded due to DNA damage, thus preventing the transcription complex from accessing any gene 19 . We also report the proximity of the parasite to the host cell nucleus 18 . Thus, the interaction between T. cruzi and the host cell nucleus reinforces the idea that T. cruzi modulates several host responses and may affect the integrity of the host cell DNA.…”

“…More recently, we have shown that T. cruzi modulated transcription and splicing machinery within the host cell, causing alterations in the host RNA polymerase II activity with downregulation of the ribonucleoproteins associated with mRNA transcription and hijacking the auxiliary splicing factor U2AF35 18 . It has been reported that RNA Pol II can be rapidly blocked or degraded due to DNA damage, thus preventing the transcription complex from accessing any gene 19 .…”