Li Wu: All right, good afternoon, I'm Li Wu. I'm professor of Veterinary Bioscience Department. I also have a joint appointment in the Department of Microbiology and Microbial Infection and Immunity here in the College of Medicine. I'm very happy to introduce you some of the work we are doing. It's a very brief highlight, and if you wanna know more about the details of our research, you can simply Google "Li Wu Lab." [Text on screen Li Wu Lab Research Highlights] First of all, I like to share my mission of the lab. So, the simple aims I try to think and try to work together with the student are those three. I wanna generate a innovative and productive research program together with the trainee. I envision all the trainees' success as my own success, and the lab has been a very enjoyable learning environment. We learn, we criticize from each other, we help each other; it's a very fun team environment. And the last point is very important for any graduate student and postdocs. I tend to facilitate their career development, no matter which path you would like to go. [Text on screen Mission of Lab: Research & Training Innovative and productive research Enjoyable learning environment Rewarding career development] [Image on screen The word career is written with the letters climbing up stairs] The main focus of the lab is based on virus HIV, particularly interaction with the host factors. When I say host factor, including host protein and viral protein, in addition to host RNA. And we studied this interaction because we wanna understand the mechanism of how virus replicates in cell, and how does this interaction can teach us to develop better antiviral strategy. And there's a new project we have been exploring for about two years. We learned from our HIV study, a enzyme I want to introduce to you cannot only block HIV, we think it also plays a role as a tumor suppressor. So this is the project we are working on, using T-cell lymphoma as a model. [Text on screen Wu Lab Research Interests and Projects Research Interests: -Mechanisms of HIV replication and pathogenesis; -HIV interactions with host factors; -Molecular mechanisms of T-cell lymphoma] [Image on screen HIV attacking human immune cell and hands in the form of a heart labeled "HIV" and "Cancer"] So currently, I have four NIH-funded projects, including three focusing on HIV and host factor interaction, mainly protein and RNA, and one of the cancer biology projects we tried to learn. [Text on screen Currently 4 NIH-funded projects in the Wu lab: -Three projects on HIV-host cell interactions; -One on cancer biology of T-cell lymphomas] The enzyme we studied to block HIV can also function as a tumor suppressor. So, HIV is a very simple virus; it only contains nine genes encoding 15 proteins. However, if you look at the size and the genome organization between a virus and the cell, you think virus is tiny and very simple. [Text on screen Simple HIV vs. Host cell: Hiv: -9 genes -15 proteins -9,700 bases Human cell: -20,000 genes -18,000 proteins -3.3 billion base pairs] So this is a picture we took, and you can see a very nice dendritic cell, a very typical morphology of antigen-presenting cell. [Image on screen -Microscopic photo of an HIV cell, labeled 0.1 μm. -Microscopic photo of a human cell, labeled 25 μm] The size is about 254 bigger than the virus particle, like HIV here. And in this paper, we describe the mechanism of HIV cell-to-cell spreading. And we learned a lot of virus and host interaction. Here, I quote a word from a journalist who writes special report for HIV discovery. He says, "HIV is ridiculously simple, yet astonishingly complex." How complex HIV could be because this is all due to HIV and host interaction. [Text on screen "HIV is ridiculously simple yet astonishingly complex. John Cohen, Science, 2008] There are about 200 more genes involved in HIV replication. Those are positive factors helping HIV to replicate in human cells. And at the protein level, there are more than 400 proteins involved in HIV replication cycle. As you can imagine, how complicated this interaction could be. [Text on screen Complex HIV-Host Interactions HIV replication involves: > 250 Human genes ~ 435 human proteins Brass et al. Science. 2008 Zhou et al. Cell Host Microbe. 2008 Jager et al. Nature. 2012] We studied dendritic cell because we want to understand the virus and host interaction, and we know HIV can get into the cell. But viral replication is very limited, restricted in this type of a cell. [Text on screen Immune Cells Fight HI HIV (microscopic black and white image of HIV cells) --> Dendritic Cells (microscopic green image of dendritic cells), Steinman, Nat. Med, 2007] [Image on screen stop sign displaying the message "STOP HIV"] Why is that? We and other many labs spend years to understand this mechanism. It turned out a very important enzyme in our cell, called SAMHD1, plays a critical role to limit HIV replication by removing the DNA building block, which is the dNTP. [Image on screen A diagram that shows Dentric cell leading into degradation, leading into SAMHD1.] And what's the SAMHD1 enzyme? How does this work? [Text on screen What is SAMHD1? How does it work?] This has been our main topic, and to understand the deep mechanism. Here, I just wanna give you a very brief introduction about the main work we have been doing. As you know, DNA building blocks are those dNTP. They are critical component to the synthesized cellular DNA. Just like we use bricks to build a nice house, but HIV steals those dNTP, the DNA building block, to synthesize viral seeding. And you can imagine if the enzyme SAMHD1 degree this dNTP component make it less efficient to be incorporated in the virus. Then, HIV replication will be limited or restricted. [Images on screen HIV Steals DNA Parts: Image 1: Diagram of molecule labeled dNTP (deoxynucleotide triphosphate). Components shown: sugar, base, and three red phosphate groups. Image 2: DBA strand labeled Cellular DNA Image 3: Cartoon of a thief running with a "dNTP" labeled object. Image 4: Image of bricks with an arrow pointing to an image of a brick house.] And this is a very critical enzyme in our cell to maintain the dNTP cellular homeostasis. And this balance is critical for DNA replication for many cell functions. [Image on screen SAMHD1: dNTP Regulator: A diagram of a molecule labeled dNTP with sugar, base, and three red phosphate groups connected. An Arrow labeled "SAMHD1 breaks down" connects this image to an image labeled dN + PPP. dn + ppp contains the sugar and base connected, with the three red phosphate groups not connected. Beneath the entire diagram is a balance scale.] And now we learned from many other studies and including our work, SAMHD1 block HIV cDNA synthesized by lowering the dNTP pool. And this is particularly true in non-dividing cell, particularly immune cell. Like a CD4 positive T cell, those are resting cells or non-dividing mitral lineage cell for antigen presentation. [Text on screen: SAMHD1 cuts the power to HIV] [Image on screen Wire cutters seen cutting a wire] So basically, you can imagine the supply of DNA replication of HIV replication needs as dNTP. If SAMHD1 cuts this supply, then viral replication can be blocked. Very simplified result showing here. [Graph: Bar graph showing that HIV infection levels are significantly higher in the absence of SAMHD1] If we have SAMHD1 in the cell, the viral replication is blocked. But if we use a special viral protein to degrade the SAMHD1, we can increase the viral infection over 44. This correlates very well with increased dNTP. And therefore, by lowering the dNTP pool in the cell, SAMHD1, can block HIV replication. [Graph: Bar graph showing that dNTP in cells is significantly higher when SAMHD1 is absent.] Of course, we wanna know more about this enzyme, including it is a function in regulating dNTP pool in the cell. And how does this enzyme not only restrict HIV, but many different RNA and DNA viruses? [Text on screen Critical Roles of SAMHD1: -Regulates dNTP levels -Restricts viral infections] Lastly, what's the physiology function of this enzyme? We think it is important to maintain genome stability. Therefore, it can play a very important role to be an anti-tumor factor. So we are exploring these three aspects of the enzyme activity. [Text on screen Critical Roles of SAMHD1: -Regulates dNTP levels -Restricts viral infections -Maintains genome stability] I'm not going to go details about each step of our life cycle, we look at the enzymes activity and also look at the mechanism of restriction. [Text on screen Mechanisms of SAMHD1-Mediated HIV-1 Restriction in Cells] [Image on screen Diagram of myeloid cell or CD4+ cell showing process of HIV-1 restriction] So I'd like to spend last 2-3 minutes to discuss a very new area of our study. As you probably heard, this is cellular-only modification. By adding a special methylation group in adenosine, this process is reversible, and it is critical for post-translational gene regulation. What we learned last couple of years is RNA and the DNA virus, their viral genome, can be modified through this DNA methylation mechanism. [Text on screen N6-methyladenosine modification: small change, but big impact -Critical for post-transcriptional gene regulation -Essential for embryonic development in plants and mammals.] And particularly, last year, we and the other two labs we discovered HIV RNA genome can be modified by m6A, this particular adenosine methylation. And it is very critical to regulate the viral replication efficiency. [Text on screen RNA modifications go viral] [Image on screen Table displaying viruses encoding RNAs with reported m6A residues] I'm not going to go into details, but you can see, using a cross-linking immune precipitation assay combined with RNA sequencing, we identify more than five peaks of this m6A modification in HIV genome. [Text on screen Mapping YTHDF binding sites in HIV-1 genomic RNA using CLIP-RNA-seq] [Image on screen Graph illustrating Nucleotide position in HIV-1 genome based on read density] Now, we are dissecting each of those modified regions to look at their contribution to viral replication. And this will be a very fun and very exciting project for students. And also we have very rapid going collaboration. To summarize this part. We think this modification, identified only a few years ago in regulating host mRNA, can also play an important role in regulating HIV and other virus replication. [Text on screen Summary and proposed mechanisms: m6A of HIV-1 RNA -maintains a dynamic equilibrium in HIV-1-infected cells; -represents a novel epigenetic mechanism regulating HIV-1 replication in host cells.] [Image on screen Diagram of CD4' T-Cell with labels] This represents a novel mechanism at the epigenetical level to regulate viral replication. So there are three group of those host protein to add the methylation; we call it "writers", and there are group of protein to remove this methylation; we call it "erasers," and there are group of protein to recognize this m6A-modified RNA; they are called a "readers". We are working on each categories of those proteins to look at the their function in regulating HIV replication. So why you wanna join us? I think we have a very nice microenvironment to be a very stimulating and collaborative study place for graduate student. We have a weekly lab meeting, and this is a really interdisciplinary study. It ranges from very basic biochemistry, cell biology, virology, and immunology. And we have a very good interaction with both students and fellows, and faculty. So what do I expect? Students who like to work hard and be motivated in my lab. I want you to be passionate about your project and also be a very fun team player. And we face a lot of challenges, like many other areas, but I think this can be really great team efforts. [Text on screen Join us: Center for Retrovirus Research ->10 active Pls at OSU -Interdisciplinary research -Interaction w/current graduate students and postdocs -Weekly seminars and meetings -Annual Distinguished Research Career Award Expectations for PhD student in the Wu lab -Work hard; be motivated -Facing challenges -Passionate about projects -Team player] [Image on Screen Image 1: group image of Wu Lab team Image 2: logo of Center for Retrovirus Research] So currently, I have two graduate students. Jenna is expecting graduation next year, I hope a new student can join us. And we have those three highlighted in blue. They all have their fellowship or scholarship, or other postdocs, and the technician in the lab. And we have a senior scientist, Corine, supervise and help other nutrients' needs. So I just want to highlight some of the work that we published last year, and mainly done by graduate student and some of the postdocs. [Text on screen Wu Lab Current Members: 1) Jenna Antonucci, BS (PhD candidate*) (highlighted in blue) 2) Serena Bonifati, PhD (Postdoc) 3) Shuliang Chem, PhD (Visiting Scholar*) (highlighted in blue) 4) Karthik Kodigepalli, PhD (Postdoc) 5) Sun-Hee Kim, MS (Technician) 6) Wuxun Lu, PhD (Postdoc) 7) Zbihua Qin, MS (PhD student*) (highlighted in blue) 8) Corine St. Gelai, PhD (Senior Res. Associate) 9) Nagaraja Tirumuru, PhD (Postdoc) *Awardees of fellowships of scholarships (highlighted in blue)] [Image on screen Wu lab current members in a group photo] We focus on HIV, the first seven papers listed here. [Text on screen Wu Lab Publications in 2016: 1. Antonucci J, et al. Nature Medicine. 2. Wang F, et al. Virology 3. Li C, et al. Journal of Virology. 4. Ren XX, et al. J Biol Chem. 5. Tirumuru N, et al. eLife. 6. St. Gelais C, et al. J. Biol. Chem. 7. Bonifati S, et al. Virology. 8. Kognken R, et al. Leuukemia Research 9. Kodigepalli KM, et al. Cell Cycle. #1-7: HIV-1 research #1-4: by PhD students #3-4: collaborations #8-9: Cancer research #8: by a PhD student] And also, we have new studies working on this cancer model, but still focusing on the same enzyme, SAMHD1. And I'd be happy to take any question if you have, thanks. My lab is in the west side of the river, it's a veterinarian medical school. Actually, I walked there. It took me about eight minutes. I think it's a very nice walk, if you like, across the river. And the Center for Retroviral Research I just mentioned is located in vet school, and we have four labs primarily focusing on human retroviruses. Three of us study HIV, so we have a very good microenvironment, and it would be fun to have more students and new students join us. Thanks.