The Role of Long Noncoding RNAs in Monocyte Growth

Monocytes are the largest type of white blood cell in our blood. They are important for our immune system, acting like the body’s first line of defense against germs and other problems. Monocytes can identify signs of trouble, multiply, and move to where they are needed. Once they reach the affected area, they change into macrophages or dendritic cells, both of which help the body deal with infection and inflammation.

When everything is running smoothly, monocytes live for just a short time and then die off in a normal way. However, if there are too many monocytes, this can lead to various health issues such as cancer, heart disease, and other problems.

#What Are Long Noncoding RNAs?

Long noncoding RNAs (or lncRNAs for short) are a type of RNA produced by our genes, but they do not turn into proteins like most other types of RNA. They are longer than 500 nucleotides and can be helpful in many biological functions, such as how cells grow and develop.

Despite their importance, scientists still don’t know what most lncRNAs do. One of the problems in studying these molecules is that there hasn’t been an easy way to target them. Traditional methods used for studying genes worked for those that make proteins but not so much for lncRNAs. However, a new version of the CRISPR technique, called CRISPR inhibition (CRISPRi), has proven to be a useful tool. This method can silence lncRNA activity, helping scientists learn more about them.

There has been some research on lncRNAs in human monocytes, but we still have a lot to learn. We aimed to uncover how these lncRNAs might influence monocyte growth and reproduction.

#Screening for Important lncRNAs

In a recent study, researchers looked at which lncRNAs are essential in human cells. They analyzed seven different cell types and identified a total of 499 lncRNAs. A surprising finding was that many of these lncRNAs acted differently depending on the cell type, showing how specific they are.

Our research took a similar approach to pinpoint which lncRNAs are important for monocytes. We created a special lncRNA library and tested it on THP1 Cells, a type of monocyte. Out of the top 35 lncRNAs we found, most of them were not the usual suspects.

We focused on two lncRNAs called OLMALINC and LNCRMP. Initial tests showed that both these lncRNAs play roles in helping THP1 cells grow. OLMALINC appears to affect the cell cycle, while LNCRMP has an impact on immune signaling and apoptosis, which is the process of programmed cell death.

#How We Conducted Our Research

To identify which lncRNAs support monocyte growth, we first prepared a library of lncRNAs specifically for monocytic cells. This library contained around 25,000 individual pieces of information targeting nearly 2,342 different lncRNAs.

We infected THP1 cells with this library and began screening. After a selection period, we checked which lncRNA guides had dropped out or flourished over time. The genes that helped THP1 growth were categorized based on how well they did in this test. We found several lncRNAs that seemed to have an important role in supporting monocyte survival.

#Important Findings: OLMALINC and LNCRMP

We focused on OLMALINC and LNCRMP because they had shown the most promise. We created three different lines of THP1 cells, each targeting one of these lncRNAs to see how they influenced cell growth.

After confirming that we had effectively decreased the levels of these lncRNAs, we proceeded with an experiment to observe how they affected cell growth. By mixing cells with and without the lncRNA changes, we could see how their presence or absence affected the growth over time. The results showed that both OLMALINC and LNCRMP were critical for THP1 cell growth.

#The Role of OLMALINC

OLMALINC is known to regulate a nearby coding gene called SCD. When we knocked down OLMALINC in THP1 cells, we noted a drop in SCD levels, suggesting that OLMALINC influences SCD's expression.

We also looked at various proteins affected when OLMALINC was knocked down, revealing it regulated several important processes, including the cell cycle and immune response. Plus, OLMALINC is mostly found in the cytoplasm of cells, indicating it plays a big part in cell functions.

Interestingly, our research hints that OLMALINC might also produce short peptides, which could further influence how monocytes grow and operate.

#The Role of LNCRMP

Similarly, LNCRMP also showed a strong connection to nearby IRF8, a gene known to impact immune cell viability. When we reduced LNCRMP, we observed a slight decrease in IRF8 levels, suggesting that LNCRMP plays a role in regulating IRF8.

We found that LNCRMP, like OLMALINC, is expressed both in the cytoplasm and the nucleus of cells. This dual presence suggests it could influence cell functions in different ways, including potential effects outside of regulating IRF8.

#Conclusion

This study highlights the importance of lncRNAs like OLMALINC and LNCRMP in the growth and function of monocytes. They help these immune cells respond to threats effectively.

What’s really interesting is that neither of these lncRNAs had been previously connected to monocyte function before our work. This shows how unique and cell-type specific these lncRNAs can be. It also emphasizes the need for ongoing research to fully understand their roles in health and disease.

Learning about lncRNAs not only helps us comprehend our bodies better but also opens doors to new treatments for diseases related to immune response. Stay tuned-there’s more to come in this exciting field of research!