Carla Dib

All Publications

• Targeted hematopoietic stem cell depletion through SCF-blockade. Stem cell research & therapy Chan, Y. Y., Ho, P. Y., Dib, C., Swartzrock, L., Rayburn, M., Willner, H., Ko, E., Ho, K., Down, J. D., Wilkinson, A. C., Nakauchi, H., Denis, M., Cool, T., Czechowicz, A. 2024; 15 (1): 387

  Abstract

  Hematopoietic stem cell transplantation (HSCT) is a curative treatment for many diverse blood and immune diseases. However, HSCT regimens currently commonly utilize genotoxic chemotherapy and/or total body irradiation (TBI) conditioning which causes significant morbidity and mortality through inducing broad tissue damage triggering infections, graft vs. host disease, infertility, and secondary cancers. We previously demonstrated that targeted monoclonal antibody (mAb)-based HSC depletion with anti(α)-CD117 mAbs could be an effective alternative conditioning approach for HSCT without toxicity in severe combined immunodeficiency (SCID) mouse models, which has prompted parallel clinical αCD117 mAbs to be developed and tested as conditioning agents in clinical trials starting with treatment of patients with SCID. Subsequent efforts have built upon this work to develop various combination approaches, though none are optimal and how any of these mAbs fully function is unknown.To improve efficacy of mAb-based conditioning as a stand-alone conditioning approach for all HSCT settings, it is critical to understand the mechanistic action of αCD117 mAbs on HSCs. Here, we compare the antagonistic properties of αCD117 mAb clones including ACK2, 2B8, and 3C11 as well as ACK2 fragments in vitro and in vivo in both SCID and wildtype (WT) mouse models. Further, to augment efficacy, combination regimens were also explored.We confirm that only ACK2 inhibits SCF binding fully and prevents HSC proliferation in vitro. Further, we verify that this corresponds to HSC depletion in vivo and donor engraftment post HSCT in SCID mice. We also show that SCF-blocking αCD117 mAb fragment derivatives retain similar HSC depletion capacity with enhanced engraftment post HSCT in SCID settings, but only full αCD117 mAb ACK2 in combination with αCD47 mAb enables enhanced donor HSC engraftment in WT settings, highlighting that the Fc region is not required for single-agent efficacy in SCID settings but is required in immunocompetent settings. This combination was the only non-genotoxic conditioning approach that enabled robust donor engraftment post HSCT in WT mice.These findings shed new insights into the mechanism of αCD117 mAb-mediated HSC depletion. Further, they highlight multiple approaches for efficacy in SCID settings and optimal combinations for WT settings. This work is likely to aid in the development of clinical non-genotoxic HSCT conditioning approaches that could benefit millions of people world-wide.

  View details for DOI 10.1186/s13287-024-03981-0

  View details for PubMedID 39473008

  View details for PubMedCentralID PMC11523590

• In Utero Hematopoietic Stem Cell Transplantation for Fanconi Anemia. Blood advances Swartzrock, L., Dib, C., Denis, M., Willner, H., Ho, K., Haslett, E., Han, J., Pan, W., Byrne-Steele, M., Brown, B., Krampf, M. R., Girsen, A., Blumenfeld, Y. J., El-Sayed, Y. Y., Roncarolo, M. G., MacKenzie, T. C., Czechowicz, A. D. 2024

  View details for DOI 10.1182/bloodadvances.2023011894

  View details for PubMedID 38991119

• Exchange of subtelomeric regions between chromosomes 4q and 10q reverts the FSHD genotype and phenotype SCIENCE ADVANCES Ma, Y., Schwager (Karpukhina), A., Dib, C., Gautier, C., Hermine, O., Allemand, E., Vassetzky, Y. S. 2024; 10 (18): eadl1922

  Abstract

  The most common form of facioscapulohumeral dystrophy (FSHD1) is caused by a partial loss of the D4Z4 macrosatellite repeat array in the subtelomeric region of chromosome 4. Patients with FSHD1 typically carry 1 to 10 D4Z4 repeats, whereas nonaffected individuals have 11 to 150 repeats. The ~150-kilobyte subtelomeric region of the chromosome 10q exhibits a ~99% sequence identity to the 4q, including the D4Z4 array. Nevertheless, contractions of the chr10 array do not cause FSHD or any known disease, as in most people D4Z4 array on chr10 is flanked by the nonfunctional polyadenylation signal, not permitting the DUX4 expression. Here, we attempted to correct the FSHD genotype by a CRISPR-Cas9-induced exchange of the chr4 and chr10 subtelomeric regions. We demonstrated that the induced t(4;10) translocation can generate recombinant genotypes translated into improved FSHD phenotype. FSHD myoblasts with the t(4;10) exhibited reduced expression of the DUX4 targets, restored PAX7 target expression, reduced sensitivity to oxidative stress, and improved differentiation capacity.

  View details for DOI 10.1126/sciadv.adl1922

  View details for Web of Science ID 001225894900022

  View details for PubMedID 38691604

  View details for PubMedCentralID PMC11062572

• Peptide nucleic acid-dependent artifact can lead to false-positive triplex gene editing signals. Proceedings of the National Academy of Sciences of the United States of America Ho, P. Y., Zhang, Z., Hayes, M. E., Curd, A., Dib, C., Rayburn, M., Tam, S. N., Srivastava, T., Hriniak, B., Li, X., Leonard, S., Wang, L., Tarighat, S., Sim, D. S., Fiandaca, M., Coull, J. M., Ebens, A., Fordyce, M., Czechowicz, A. 2021; 118 (45)

  Abstract

  Triplex gene editing relies on binding a stable peptide nucleic acid (PNA) sequence to a chromosomal target, which alters the helical structure of DNA to stimulate site-specific recombination with a single-strand DNA (ssDNA) donor template and elicits gene correction. Here, we assessed whether the codelivery of PNA and donor template encapsulated in Poly Lactic-co-Glycolic Acid (PLGA)-based nanoparticles can correct sickle cell disease and x-linked severe combined immunodeficiency. However, through this process we have identified a false-positive PCR artifact due to the intrinsic capability of PNAs to aggregate with ssDNA donor templates. Here, we show that the combination of PNA and donor templates but not either agent alone results in different degrees of aggregation that result in varying but highly reproducible levels of false-positive signal. We have identified this phenomenon in vitro and confirmed that the PNA sequences producing the highest supposed correction in vitro are not active in vivo in both disease models, which highlights the importance of interrogating and eliminating carryover of ssDNA donor templates in assessing various gene editing technologies such as PNA-mediated gene editing.

  View details for DOI 10.1073/pnas.2109175118

  View details for PubMedID 34732575

• Control of DUX4 Expression in Facioscapulohumeral Muscular Dystrophy and Cancer. Trends in molecular medicine Karpukhina, A., Tiukacheva, E., Dib, C., Vassetzky, Y. S. 2021

  Abstract

  DUX4, a gene encoding a transcription factor involved in early embryogenesis, is located within the D4Z4 subtelomeric repeat on chromosome 4q35. In most healthy somatic tissues, DUX4 is heavily repressed by multiple genetic and epigenetic mechanisms, and its aberrant expression is linked to facioscapulohumeral muscular dystrophy (FSHD) where it has been extensively studied. Recently, DUX4 expression has been implicated in oncogenesis, although this is much less explored. In this review, we discuss multiple levels of control of DUX4 expression, including enhancer-promoter interactions, DNA methylation, histone modifications, noncoding RNAs, and telomere positioning effect. We also connect disparate data on intrachromosomal contacts involving DUX4 and emphasize the feedback loops in DUX4 regulation. Finally, we bridge data on DUX4 in FSHD and cancer and discuss prospective approaches for future FSHD therapies and the potential outcomes of DUX4 inhibition in cancer.

  View details for DOI 10.1016/j.molmed.2021.03.008

  View details for PubMedID 33863674