Human Cell-Consuming Transformative Parasite Assumes Host's Protein Layers for Camouflage
Entamoeba histolytica, a microscopic parasite, is responsible for infecting millions each year, primarily in the Global South, causing severe health issues and resulting in nearly 70,000 deaths annually. This single-celled organism is notorious for targeting human cells, displaying a taste for tissue destruction.
In a review published in Trends in Parasitology, microbiologist Katherine Ralston from UC Davis and her colleagues Maura Ruyechan and Wesley Huang delve into the parasite's destructive mechanisms. Contrary to initial beliefs, the parasite reportedly does not simply inject toxins into cells, but instead, it seems to bite them.
Back in 2011, Ralston observed through a microscope that the amoeba was breaking off pieces of human cells. These fragments, tagged with a fluorescent dye, were visible inside the amoeba's body, suggesting a peculiar process known as trogocytosis, or "cell nibbling." In a 2014 paper published in Nature, Ralston described this process, wherein the parasite didn't just poison human cells; it fed on them, piece by piece.
Even more concerning, in 2022, the team discovered that the amoeba wasn't just eating human tissue—it was also absorbing proteins from the cell's outer membrane after ingestion. Two of those proteins, CD46 and CD55, are typically used by human cells to shield themselves from immune molecules known as complement proteins. By absorbing these proteins, the amoeba, in essence, dons a molecular disguise, making it more difficult for the immune system to detect and destroy it.
Understanding the amoeba's behavior has proven challenging due to the parasite's complex genome. Unlike other pathogens such as HIV or Salmonella, E. histolytica has a sprawling genome with a confusing structure and irregular chromosomes, making it difficult to manipulate genetically.
The team has, however, made breakthroughs in recent years. They discovered that the parasite uses RNA interference (RNAi) as a gene-silencing mechanism to fine-tune gene activity. This revelation led to the creation of a comprehensive "RNAi library" in 2021, enabling the team to observe the effects of silencing any of the parasite's approximately 8,700 genes. They aim to use RNAi in combination with CRISPR gene editing to map the amoeba's functional genome and identify essential genes involved in trogocytosis, immune evasion, or virulence.
Progress in understanding E. histolytica's behavior has been slow, but advances are being made. Scientists hope to use modern molecular tools to chart a new path forward, leading to improved diagnostic methods and targeted therapies for this leading cause of death from diarrheal disease in children. Despite the challenges, Ralston's work promises new insights into this enigmatic parasite.
- The field of science is continually progressing in its understanding of Entamoeba histolytica, a microscopic parasite responsible for millions of health issues and annual deaths, with researchers utilizing modern technology such as RNA interference (RNAi) and CRISPR gene editing to unravel the parasite's mechanisms.
- In the realm of medical-conditions, Entamoeba histolytica presents a significant challenge due to its complex genome and irregular chromosomes, making it difficult to manipulate genetically, but advances in research have led to the creation of a comprehensive RNAi library for a more thorough examination of the parasite's genes.
- In the health-and-wellness sphere, the immune system struggles to combat Entamoeba histolytica due to its ability to absorb proteins from human cell membranes, effectively disguising itself, a factor that makes targeted therapies all the more crucial.
- Fitness-and-exercise are not typically associated with Entamoeba histolytica, but staying active and maintaining a healthy lifestyle can help boost the immune system's ability to fight off infections such as this parasite, making it an essential aspect of overall health and well-being.
