Effects of ZNF467 on HSPC fitness and Promotion of Follicular Lymphoma via DC-SIGN

Summary

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Blood Podcast, April 30, 2026:

Main Theme

In this episode, Dr. James Griffin explores two significant studies in hematology. The first discussion with Dr. Bin Guo examines how ZNF467 influences the mechanical properties and engraftment efficiency of human hematopoietic stem cells (HSCs). The second segment features Dr. Francesco Forconi, who delves into how DC-SIGN binding to oligomannose glycans on follicular lymphoma cells promotes their adhesion and survival. Both segments highlight groundbreaking research published recently in Blood.

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Segment 1: ZNF467 and Hematopoietic Stem Cell Fitness

With Dr. Bin Guo
Paper: "Nucleoplasmic ZNF467 condensates boost hematopoietic stem cell engraftment via ICAM1 mediated mechanical reprogramming"
Timestamps: [00:39] – [10:18]

Key Discussion Points & Insights

• Research Motivation & Background

  • The study begins with the question: What gives HSCs their unique ability to regenerate the blood system, compared to multipotent progenitors (MPPs)?
  • Inspired by the field of mechanobiology, Dr. Guo and colleagues hypothesized that HSCs might have an intrinsic mechanical signature vital for their engraftment and survival ([01:22]).

• Major Findings

  • Mechanical Properties of HSCs:

    • Using atomic force microscopy and biophysical tools, HSCs were confirmed to be mechanically stiffer, more adhesive, and generated more traction force than MPPs.
      • “They are simply mechanically tougher.” – Dr. Bin Guo [02:57]

  • Role of ZNF467:

    • ZNF467, a transcription factor, is highly enriched in HSCs relative to MPPs. Knockdown of this gene led to “floppy” cells that couldn’t adhere or engraft ([03:28]).
    • Overexpression of wild-type ZNF467 did not improve engraftment—likely due to nuclear retention.
    • A mutant form, MPZNF467, forced into the nucleoplasm, created condensates that strongly activated a “mechanoresponsive gene program,” notably upregulating ICAM1 on the cell surface ([04:07]).
      • “By boosting ICAM1 via these condensates, we made the cells physically stronger and saw a significant increase in functional repopulating stem cells in our mouse models.” – Dr. Guo [04:28]

  • ICAM1 as Key Effector

    • ICAM1’s function in HSCs had been underappreciated. This study demonstrates it as a “crucial mechanical ankle” for stem cell integrity and engraftment ([04:48]).
    • Rescue experiments: Neutralizing ICAM1 abolished the benefits of MPZNF467 expression, confirming it as the essential downstream target ([08:55]).

• Significance

  • This is the first study to reveal ZNF467’s function in human HSCs ([06:22]).
  • Defines a new mechanistic pathway for enhancing stem cell transplantation efficacy.

Notable Quotes & Memorable Moments

• “We are inspired by growing field of mechanobiology. We know stem cells respond to physical in the niche like stiffness or shear stress. But we flipped the question: do hematopoietic stem cells have a distinct mechanical signature that allows them to withstand the stress of transplantation and squeeze into the bone marrow niche?”
  – Dr. Bin Guo [01:50]
• “ZNF467 is essential for the mechanical integrity of the stem cells.”
  – Dr. Bin Guo [03:34]
• “The star of that program was ICAM1 on the cell surface. It turns out ICAM1 isn't just for endothelial cells, it's a crucial mechanical anchor for HSC itself.”
  – Dr. Bin Guo [04:13]
• “We think ICAM1 plays the key role in MPZNF467-mediated enhancement... but we cannot exclude that other genes are also functioning in this process.”
  – Dr. Bin Guo [09:45]

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Segment 2: DC-SIGN and Follicular Lymphoma Survival

With Dr. Francesco Forconi
Paper: "DC-SIGN binding to the surface immunoglobulin oligomannose-type glycans promotes follicular lymphoma cell adhesion and survival"
Timestamps: [10:20] – [21:52]

Key Discussion Points & Insights

• Background on Oligomannose Glycosylation in Lymphoma

  • Follicular lymphoma cells alter the B cell receptor (BCR) by adding oligomannose-type glycans, which enables interaction with DC-SIGN, a lectin on macrophages and dendritic cells ([10:51]).
  • This glycosylation blocks antigen binding, fundamentally altering cell survival cues compared to normal B cells.

• Three Main Findings

  1. BCR Reorganization:

     • DC-SIGN binding reorganizes the BCR on lymphoma cells—providing enough signal for survival, but not enough to induce endocytosis or cell death ([12:23]).

  2. Promotion of Cell Adhesion:

     • The interaction with DC-SIGN promotes lymphoma cell adhesion in lymphoid tissue via the adhesion molecule VCM1, further aiding survival in the correct microenvironment ([13:15]).

  3. Survival Dependency:

     • Direct interaction with DC-SIGN-positive cells is required for lymphoma cell survival; blocking this interaction leads to cell death ([14:55]).
     • “If you block these interaction, then the cells detach, do not adhere and die. I think this is the most important element that paves the way for further therapeutical investigations.” – Dr. Forconi [15:38]

• Challenges and Therapeutic Implications

  • Mouse models are ineffective due to the lack of DC-SIGN in mice; alternatives like organoids and direct patient studies are now being pursued ([16:45]).
  • The process differs from purely genetically driven cancers; follicular lymphoma “exploits what is normally present in our B cells” ([18:06]).
  • Glycan addition is a result of selective pressure during somatic hypermutation, ensuring survival signals without triggering cell death ([18:44]).

• Prognostic Value of Mannose Modification

  • In diffuse large B cell lymphoma, the presence of these modifications is associated with more aggressive disease ([20:04]).
  • In follicular lymphoma, most cases are IGMAN positive, and signaling strength is related to the number of mannoses—the degree of interaction with DC-SIGN, not just glycan levels ([20:52]).

Notable Quotes & Memorable Moments

• “The tumor deliberately blocks the antigen binding at the B cell receptor by inserting these sugars, these mannoses. We call the complex IgMan... with this design, they will instead survive.”
  – Dr. Forconi [11:32]
• “This configuration doesn't just provide survival signals, it protects the cell from the kind of high affinity BCR engagement that... would lead the B cell to die.”
  – Dr. Forconi [13:44]
• “There is always an attraction and a desire to have these models done in mice. But mice do not express DC-SIGN. Therefore, it's impossible to mimic such a model...”
  – Dr. Forconi [16:46]
• “The mechanism ... is a finalistic process that the tumor cells themselves actively choose out of the somatic hypermutation process to find the right sugar in this case, so that you have the right ligand DC-SIGN in this case for the right level of signal that will not lead to death, but will keep the cell alive.”
  – Dr. Forconi [18:44]

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Important Timestamps

• ZNF467 and HSC Mechanics:

  • [01:22] – Study motivation and initial findings
  • [03:28] – Role of ZNF467 in HSCs
  • [04:07] – MPZNF467 condensates and ICAM1 activation
  • [08:55] – Functional proof: neutralizing ICAM1

• DC-SIGN and Lymphoma:

  • [10:51] – Context for mannose modification in lymphoma
  • [12:23] – How DC-SIGN engagement reorganizes BCR
  • [13:15] – DC-SIGN and cell adhesion
  • [14:55] – Blocking interactions reduces survival
  • [16:45] – Challenges in in-vivo modeling
  • [20:04] – Prognostic implications of glycan modifications

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Takeaway

This episode highlights major advances in understanding the biophysical properties governing hematopoietic stem cell engraftment and the microenvironmental mechanisms supporting follicular lymphoma survival. Both studies open new avenues for regenerative medicine and lymphoma therapy, emphasizing the value of translational mechanistic research in hematology.

Transcript

[A]

Welcome to the American Society of Hematology Conversations with Blood Authors Podcast this Blood Podcast episode is hosted by Dr. James Griffin from the Dana Farber Cancer Institute in Boston. In this episode he discusses nucleoplasmic ZNF467 condensates boost hematopoietic stem cell engraftment via ICAM1 mediated mechanical reprogramming with Dr. Bin Guo. He also talked with Dr. Francesco Fraconi and his article on DC Sing binding to the surface I oligominose type Glycans Promotes Follicular Lymphoma Cell adhesion and survival

[B]

hello everyone, my name is James Griffin. I'm one of the associate editors for Blood on the podcast sections and we have two terrific papers today. The first one that is going to be presented is entitled Nucleoplasmic ZNF467 condensates boost hematopoietic stem cell engraftment via ICAM1 mediated mechanical reprogramming. It's going to be presented by Dr. Bin Guoa, who is in Shanghai, has a number of affiliations and I'll just mention that he is affiliated with the Department of Hematology at the Xinhua Hospital, which is affiliated with the Shanghai Jiaotong University school of medicine.

[C]

Dr. Guala hi Dr. Griffin, thank you very much for having me on Blood Podcast to discuss our recent published study in blood. First, I would like to give a little background to the audience. This project really started from a very fundamental question in stem cell biology. We know hemopathic stem cells, or HSC are remarkable. They can regenerate the entire blood system for a lifetime, whereas their immediate downstream neighbor cells, the multiprotent progenitors or mpp, cannot. For years, many groups in the field have studied the biomechanical differences including quiescence metabolism and protein synthesis activity. But we started to wonder, is there also an intrinsic physical or mechanical difference between HSC and mechanical multiple dental progeny cells? We are inspired by growing field of mechanobiology. We know stem cells respond to physical in the niche like stiffness or sheer stress. But we flipped the question do hematopoietic stem cells have a distinct mechanical signature that allows them to withstand the stress of transplantation and squeeze into the bone marrow niche? And if so, what gene controls that? That's what kicked off this whole investigation. In this study we had several key findings that we think are quite exciting. First, using atomic force microscopy and other biophysical tools, we confirmed that human hematopoietic stem cells are indeed stiffer, more adhesive and generate more traction force than multipotent protegen cells. They are simply mechanically tougher. And second, we identified a transcription factor called ZNF4637 that is highly enriched in hematopoietic stem cells. If we knock down this gene, the cells become floppy, they lose stiffness, they cannot adhere and they fail to engraft in mice. ZNF4667 is essential for the mechanical integrity of the stem cells and the surprising part came when we tried to over express this gene. Putting in more full length or wide type than F467 didn't help the engraftment of stem cells. It actually got stuck in the nucleus upon overexpression. But we engineered a mutant form that deleted a specific domain which forced the protein into the nucleoplasm. We call it MPZNF467. This MPZNF467 formed phase separated condensates in the nucleus and this act of condensing massively activated a mechanoresponsive gene program. The star of that program was ICN1 on the cell surface. It turns out ICN1 isn't adjustable endothelial cells, it's a crucial mechanical ankle HSC itself. By boosting ICAN1 via these condensates, we made the cells physically stronger and saw a significant increase in functional repopulating stem cells in our mouse models. In summary, we demonstrated that human hemopathic stem cells possess distinct biomechanical advantages including enhanced stiffness, adhesion, traction force generation and migratory capacity that functionally differentiated them from multipotent protonate cells. The key regulator in this process is ZNF467 engineered MP. ZNF467 condensates enhance hematopoietic stem cell engraftment efficiency via ICN1 mediated mechanical reprogramming.

[B]

Thank you very much. I have a couple of questions about ZNF467. I understand from your paper that the function of this particular zinc finger protein wasn't really known before your studies on hematopoietic stem cells and that you identified it by looking for transcriptomic differences between HSC and MPPS. How did you end up focusing on ZNF467? I'm guessing there were a lot of differences in gene expression in those two populations.

[C]

We compiled the expression differentially expressed genes between human chord, blood, hemopatic cell and progeny cells. We found some known genes, for example half and AVP, and the most significant gene is Zn467 except AVP and HLF, which are two microgenes of GMO hematopoietic stem cell. And since the function of Zm467 in human cells or tissues is largely unknown, the only thing we know about ZN467 is about its role in regulation of adipogenesis and osteogenesis in mouse bone marrow and its precise biological function in human cells remain largely undefined. So actually our present study is the first to reveal the function of ZNN467 in human cells. Why we focus this gene in hemopathic stem cell is because it's a zinc finger domain containing genes and there is a potential transcription factor. And the transcription regulation in hemopathic stem cells is very interesting. That's why we pick up this gene and to further explore its function or mechanism in regulation of human hemopathic cell function.

[B]

Great. You made the observation that ZNF467 is responsible for increased expression of ICAM1 and that this is probably important in these mechanical properties of hematopoietic stem cells. Do you think that all of the effects of ZNF467 are due to increased expression of IC or are there other activities as well?

[C]

That's a very good question. Actually we did the transcription analysis upon overexpression of MP ZNF467 and then we did the pathway enrichment analysis. So the most significant pathway is about the migratory or chemotaxis associated pathways and also mechanical response pathways. And of course a lot of genes are changed upon overexpression of MP ZM467 or after knocking down of ZM467. Some of the genes is already reported in regulation of Stenis including MMP9 and Vacant1. Why we focus on IK1 is because the previous studies mostly focus on ICAN1 in endothelial cells. So the intrinsic function of ICAN1 in hemopathic stem cells is still unknown. And because it's expressed on cell surface in hemopathic stem cells, overexpression of MPCM467 stimulate its expression bind to the promoter of ICANN1 and activated its transcription and activated the whole mechanical response gene program. And so we hypothesized that ICAN1 may be involved in regulation of the mechanical adaptation of hemopathic stem cells. And we guessed that ICAN1 is a major downstream target agents of ZM467 because we did the rescue experiments, we knock down the ICANN1 or using the antibody to neutralize in the ICANN1 in MPZM467 overexpressed cells and then it totally blocked the function of MPZM467. We think IK1 plays the key role in MPZM467 mediated enhancement of lymphopathic stem cell function, but we cannot exclude that other genes are also functioning in this process.

[B]

Thank you very much, that was a terrific discussion and good luck with your future studies in this really interesting area of stem cell biology.

[C]

Thank you Dr. Griffin.

[B]

We're going to go on to our second paper which is entitled DC Sign Binding to the Surface Immunoglobulin Oligomanose Type Glycans Promotes Follicular Lymphoma Cell Adhesion and Survival. This paper is going to be discussed by Dr. Francesco Forconi, who's in the Cancer Sciences and Cancer Research Group at the UK Southampton Center Faculty of Medicine, University of Southampton in Southampton, UK.

[D]

Dr. Forconi thank you very much Dr. Griffin for the invitation and thank you for for participating to this nice blood podcast. This work grew very naturally out of a long standing observation at our center in Southampton initially with Professor Freda Stevenson, my mentor in follicular lymphoma that every tumor of follicular lymphoma and every cell within the tumor, follicular lymphoma cells within the clone remodels its B cell receptor by inserting a type of sugar oligoman nose glycans into the antigen binding site. We and others had shown that this allows that the lymphoma engage a molecule, a lectin called DC sign rather than an antigen. But what wasn't clear was why this interaction was so essential. When we looked at tissue, follicular lymphoma cells were physically clustering around DC sign positive macrophages and DC sign positive follicular dendritic cells. The key question of this paper became what does this interaction actually do for the tumor in its native environment? What does the microenvironment does? Additional background and context was despite being a cancer germinal center, B cells, while under normal circumstances B cells survive only if they receive the right signal from antigen in the presence of T cells, stromal cells and cytokines, the right antigen in follicular lymphoma, the tumor deliberately blocks the antigen binding at the B cell receptor by inserting these sugars, these manoses we call the complex igman. By having Igman in the absence of the other environmental elements that an antigen interaction would require, the cells with antigen would die. With this design, they will instead survive. Our study has out summarized three fundamental findings. 1. DC Sign reorganizes the B cell receptor which is the functional unit for any normal and tumour B cells. It reorganizes the B cell receptor at the cell surface in a very specific way. Enough to signal but not enough to trigger antigen mediated endocytosis. Not enough to trigger endocytosis and or cell death. The second point is that this engagement actively promotes adhesion of lymphoma cells to WCM1, which is very highly expressed in tissues, even more intensely in the follicle of a lymph node. This addition molecule will therefore promote adhesion in the right environment through classic B cell receptor proximal kinases enacting cytoskeleton. Therefore, this configuration doesn't just provide survival signals, it protects the cell from the kind of high affinity BCR engagement that without proper T cell help would lead the B cell to die. The majority of the B cells in the lymph node normally die in the big affinity and highly expensive and costly, energetically costly affinity maturation process. In a sense, the summary would be that the lymphoma cells are hiding in plain sight within the germinal center rules. Then there is the third and probably the most important observation or hint from our study that when lymphoma cells and we are talking about primary lymphoma cells, not cell lines. When lymphoma cells directly interact with DC sign expressed on follicular dendritic cells or follicular dendritic cell like elements, this interaction is required for their survival and if you block these interaction, then the cells detach, do not adhere and die. I think this is the most important element that paves the way for further therapeutical investigations.

[B]

Very nice. A couple of questions for you. You make the point that this interaction is required for the maintenance and viability of the lymphoma cells. Most of your studies, if I remember right, were done in vitro. In terms of the viability studies, have you had a chance to test the effects of blocking this interaction using an in vivo model yet?

[D]

The problem of using in vivo models is quite important because there is always an attraction and a desire to have these models done in mice. But mice do not express this design. Therefore it's impossible to mimic such a model in animal models. We, as part of an important program grant with Blood Cancer United are indeed investigating other models on how to look at this blocking interaction first potentially in organoids in 3D models. That's the ultimate goal. Use our reagents Our blocking reagents in patients directly. So it's really now the moment to bypass what is missing the animal models that do not exist, to explore the finding in the proper model, if it can be which is patients.

[B]

You've made the point that normal B cells don't have this same modification of their surface ig. Do you know yet anything about the mechanisms that lymphoma cells use to modify this molecule that normal B cells apparently suppress or don't have?

[D]

This is another very important element that distances follicular lymphoma from genetically driven conditions, very much driven by biological mechanisms that the tumor cells does nothing different by exploiting what is normally present in our B cells. So this was investigated carefully and has been and continues to be investigated by our collaborator Max Crispin here in Southampton, a glycobiologist who is able to demonstrate how the selection of the sites at very specific points within the antigen binding region is essential in order that where the forming glycan is formed is not accessible to an enzyme, a big molecule manosidase or multiple monosidases, therefore preventing the maturation of the sugar into complex glycans. So the mechanism we think we do know the machinery is completely effective. But again, it is a finalistic process that the tumor cells themselves actively choose out of the somatic hypermutation process to find the right sugar in this case, so that you have the right ligand DC sign in this case for the right level of signal that will not lead to death, but will keep the cell alive.

[B]

Is there any evidence that the level of the mannose modification on the lymphoma cell surface is an independent prognostic marker for lymphoma progression?

[D]

We have studied these thoroughly in another study which has been recently published in Blood, I think in December by one of my PhD students. Again work with Max Crispin and Frida, however, in diffuse large B cell lymphoma and demonstrated that within diffuse large B cell lymphoma the acquisition of mannosis by the B cell receptor. We call this type of diffuser atrop lymphoma man type DLBCL associates with the most aggressive behavior in gcb like the lbcl. We are now exploring and we have preliminary data suggesting that this could be the same for follicular lymphoma. But the difference is that in follicular lymphoma, the largest majority of them are IGMAN positive. Probably the IGMAN negative follicular lymphomas are a little different beast, but within that it's not really the levels it is the degree of binding that might affect, and the degree of binding might be dependable on the number of mannoses present on the B cell receptor. The numbers can BE variable between 6 and 9, and it's well known that the binding to DC sign is affected by the number of man noses. Therefore the avidity would increase and the signaling might be a little stronger. So it's not really probably the levels of the immunoglobulin, it's not the levels of the man noses, it's how much the interaction occurs.

[B]

Well, thanks very much to both of you for really terrific discussions, excellent and important research, and I will look forward to hearing about future advances of both of these projects in the near future.

[A]

Thank you for listening to this episode of Conversations with Blood Authors. To read the articles, visit bloodjournal.org this episode is copyrighted by the American Society of Hematology.