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Rossi, D.

Publications and source records attributed to Rossi, D..

15 recordsLinked to original sources

Discovery of Scrophularia nodosa harpagoside synthase, a novel BAHD cinnamoyltransferase, bridges a key gap in the iridoid biosynthetic pathway

Harpagoside, a high-value anti-inflammatory iridoid compound, is traditionally extracted from the roots of Harpagophytum procumbens (Pedaliaceae, Lamiales), a Southern African desert plant widely used in traditional medicine but currently threatened by overexploitation. Scrophularia nodosa (Scrophulariaceae, Lamiales) is a perennial annual plant widely distributed in Western Europe and accumulates several iridoid compounds with known biological activities, such as catalpol, aucubin, harpagide and particularly harpagoside. We gathered extensive genomic and transcriptomics resources for this species and aimed at deciphering the biosynthetic pathway leading to the most abundant iridoid in S. nodosa, harpagoside. We found that the early iridoid pathway is well conserved with other iridoid-producing plants and validated the enzyme activities by transient co-expression in N. benthamiana. Investigation into the large BAHD family showed subclade 6i expanding in Scrophulariaceae, with an atypical VYPWG motif instead of the canonical DFGWG. In this branch, we discovered and characterized harpagoside synthase, a BAHD-type cinnamoyl transferase enzyme showing unique high specificity to the uncommon cinnamoyl-CoA acyl donor and catalyzing the final step of harpagoside biosynthesis. These results establish S. nodosa as a new model to investigate unexplored branches of the iridoids metabolism, and are a first step towards sustainable harpagoside and high-value cinnamoyl-containing conjugates production.

plant biology↗

Meditope-Enabled Chimeric Antigen Receptors Facilitate Plug-and-Play Control of T Cells

Chimeric antigen receptor (CAR) T cells have transformed cancer treatment, yet challenges for achieving broader clinical success remain, including overcoming tumor antigen heterogeneity and limited T cell fitness. To address these challenges and enhance CAR T cell functionality, we leveraged meditope technology, a lock-and-key platform where Fab regions of antibodies are modified to bind a small cyclic peptide termed meditope (meP). We developed a panel of meditope-enabled Fab-based CARs (meCARs), which show selective binding to the meP and comparable activity to traditional single-chain variable fragment (scFv)-based CARs. Focusing on HER2-targeted meCARs for evaluating platform utility, we exploited the modularity of the meditope platform to detect meCAR T cells using meP-fused fluorescent agents, promote meCAR T cell expansion via meP-fused IL-15 cytokine, and broaden tumor antigen targeting through meP-fused antibodies to address tumor heterogeneity. These findings establish the meditope technology as a versatile strategy to augment CAR T cell functionality and overcome key limitations of current CAR-based therapies.

bioengineering↗

CDK9 pharmacological inhibition with PRT2527 has antitumor activity in marginal zone lymphoma models and can improve the effects of BTK, PI3K, and BCL2 inhibitors

Cyclin-dependent kinase 9 (CDK9) drives transcriptional elongation and supports the expression of short-lived oncogenic and anti-apoptotic proteins such as MYC and MCL1. PRT2527 is a potent, selective CDK9 inhibitor currently in early clinical development. We evaluated its preclinical activity in marginal zone lymphoma (MZL) models, including cell lines with acquired resistance to BTK, PI3K, and BCL2 inhibitors. Short exposure (4 hours) to PRT2527 produced nanomolar cytotoxicity across all tested MZL cell lines, with efficacy maintained in resistant derivatives. Transcriptomic profiling of VL51 cells showed broad gene repression, including MYC, IRF4, NF-{kappa}B-related genes, and MCL1, alongside increased expression of HLA class II genes. Moreover, comparison with additional CDK inhibitors revealed a similar transcriptional repression signature, underscoring a conserved CDK-dependent regulatory network. Protein analyses confirmed rapid depletion of MCL1, MYC, RNA polymerase II, and IRF4. Flow cytometry validated increased HLA class II and decreased HLA class I surface expression. Combination studies demonstrated additive to synergistic effects with BTK inhibition (ibrutinib) or dual PI3K/BCL2 inhibition (copanlisib plus venetoclax), independent of baseline drug sensitivity. Mechanistically, these combinations may enhance apoptosis by concurrently suppressing survival signaling and transcriptional addiction. Analysis of patient samples revealed high CDK9 expression, further supporting the biological relevance and therapeutic rationale for targeting CDK9 in this disease. Our findings support the development of CDK9-based combination strategies for relapsed/refractory MZL and other B-cell malignancies, with an additional potential for integration with immunotherapies. Key PointsO_LICDK9 inhibitor PRT2527 kills marginal zone lymphoma cells, regardless of whether they are resistant to other targeted drugs. C_LIO_LIPRT2527 boosts the effects of BTK, PI3K, and BCL2 inhibitors and alters immune-related gene expression. C_LI Draft of graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=141 SRC="FIGDIR/small/705084v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@37b9e6org.highwire.dtl.DTLVardef@8de6a5org.highwire.dtl.DTLVardef@219771org.highwire.dtl.DTLVardef@15dabfe_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Dual targeting of BTK and BCL2 enhances apoptosis in marginal zone lymphoma models: preclinical activity of BGB-16673 and sonrotoclax

BackgroundBTK and BCL2 represent key therapeutic targets in B-cell lymphomas, including marginal zone lymphoma (MZL). Here, we evaluated the novel BTK degrader BGB-16673, and the second-generation BCL2 inhibitor sonrotoclax in a panel of MZL cell lines, including models with acquired resistance to BTK, BCL2 and PI3K inhibitors, as single agents and in combination. MethodsCytotoxicity, transcriptomic changes, apoptosis, and protein expression were assessed for BGB-16673 alone and in combination with venetoclax, sonrotoclax, bendamustine, selinexor, lenalidomide, and tazemetostat. ResultsBGB-16673 demonstrated single-agent activity in selected MZL cell lines, inducing BTK degradation and transcriptional repression of BCR signaling and MYC targets. Its transcriptional and phenotypic effects overlapped with those of zanubrutinib but also included specific modulation of oxidative phosphorylation genes. Combination studies revealed that BGB-16673 synergized with other targeted agents, achieving the best results with sonrotoclax, venetoclax, bendamustine, lenalidomide, and rituximab. The mechanism of action of the combination with the BCL2 inhibitors was further evaluated. The combination with sonrotoclax consistently enhanced apoptosis across MZL models, outperforming venetoclax in potency in most cell lines. Sonrotoclax showed over 10-fold higher activity than venetoclax in three MZL lines and demonstrated synergistic interaction with BGB-16673. Mechanistically, the combination leads to BTK degradation and modulation of anti-apoptotic proteins such as BCL2, MCL1, and BCL-XL. ConclusionOur findings underscore the potential of BGB-16673 as a therapeutic agent, both as a monotherapy and in combination regimens, for treating MZL patients. Additionally, the results also identify the second-generation BCL2 inhibitor sonrotoclax as another drug to be explored in the same patient populations.

cancer biology↗

High-Throughput Screening Identifies PLK1 Inhibition as a Strategy to Potentiate BTK Blockade in Marginal Zone Lymphoma

B-cell receptor (BCR) signaling is a key therapeutic target in B-cell lymphomas, and Bruton tyrosine kinase inhibitors (BTKi) have demonstrated clinical efficacy in marginal zone lymphoma (MZL). However, the rate of complete remissions is relatively low, and resistance remains a significant clinical challenge, underscoring the need for novel combination strategies. To identify compounds that enhance the activity of BTKi and overcome resistance, we conducted a high-throughput screen of 1,695 compounds using a previously developed MZL model of acquired resistance to BTK and PI3K inhibitors derived from the Karpas1718 cell line. Thirty-three compounds showed single-agent anti-proliferative activity in the nanomolar range, both in the Karpas1718-resistant and parental cells. Based on their clinical potential in combination with BTKi, seven compounds were selected for further validation. The polo-like kinase 1 (PLK1) inhibitor rigosertib emerged as a top candidate, showing strong activity in both parental and BTKi-resistant cell lines. Combination treatment of rigosertib and BTKi zanubrutinib resulted in broad transcriptomic changes, characterized by the downregulation of pathways involved in B-cell activation, proliferation, and BCR signaling. Mechanistically, the combination reduced phosphorylation of key BCR pathway components and inhibited NF-{kappa}B nuclear translocation. These findings suggest that PLK1 inhibition can overcome BTKi resistance by further inhibiting BCR signaling through the canonical NF-{kappa}B pathway. Therefore, the dual pharmacological inhibition of BTK and PLK1 is a promising therapeutic approach for patients with MZL and warrants further preclinical and clinical investigations.

cancer biology↗

Pharmacological inhibition of CXCR4 increases the anti-tumor activity of conventional and targeted therapies in B-cell lymphoma models

BackgroundCXCR4 is a chemokine receptor frequently implicated in the pathogenesis and treatment resistance of B-cell lymphomas and other tumor types. Thus, CXCR4 targeting is explored using various approaches, including small molecules, antibodies, and short peptides. Here, we investigated the antitumor effects of the CXCR4 pharmacological inhibition with the synthetic peptides SPX5551 and balixafortide, as single agents and in combination, in various B-cell lymphoma models. MethodsBinding modalities were assessed via molecular docking and simulation. In vitro assays evaluated single-agent and combinatorial effects of CXCR4 antagonists with BTK, PI3K, and conventional therapies across 20 lymphoma cell lines, including models with acquired resistance. Transcriptomic analyses and mechanistic studies elucidated the pathways modulated by combined CXCR4 and BTK inhibition. ResultsStructural modeling confirmed similar CXCR4 binding modes for SPX5551 and balixafortide. SPX5551 displayed minimal single-agent activity but restored sensitivity to BTK and PI3K inhibitors in resistant marginal zone lymphoma (MZL) models. Across mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), and diffuse large B-cell lymphoma (DLBCL) models, SPX5551 enhanced the efficacy and/or potency of ibrutinib, copanlisib, rituximab, and R-CHOP. In MCL, co-treatment with SPX5551 and ibrutinib synergistically induced apoptosis, inhibited NF-{kappa}B and AKT signaling, and led to broader transcriptomic repression of tumor-promoting pathways compared to either agent alone. ConclusionsAlthough CXCR4 inhibitors alone show limited cytotoxicity, their combination with standard and targeted therapies significantly enhances anti-lymphoma effects, particularly in drug-resistant settings. These findings provide a strong rationale for clinical evaluation of CXCR4 blockade as a combinatorial strategy in B-cell lymphomas.

cancer biology↗

IL-16 production is a mechanism of resistance to BTK inhibitors and R-CHOP in lymphomas

Introducing Brutons tyrosine kinase (BTK) inhibitors has significantly improved outcomes for patients with B-cell malignancies and autoimmune disorders. However, resistance, either primary or acquired, remains a major clinical challenge. To better understand the underlying resistance mechanisms to BTK inhibitors, we established an ibrutinib-resistant model from a patient-derived splenic marginal zone lymphoma (MZL) cell line (VL51) through prolonged drug exposure. Resistant cells exhibited a 15-fold increase in ibrutinibs IC50, along with distinct morphological changes, mitochondrial activation, and cross-resistance to covalent, non-covalent BTK inhibitors and BTK degraders. Integrated transcriptomic, epigenomic, and proteomic analyses identified overexpression and secretion of IL-16 as a key feature of resistance, driven by chromatin remodeling and activation of the FLI1 transcription factor. IL-16 conferred ibrutinib resistance via CD9-mediated activation of the NF-{kappa}B and AKT signaling pathways and was found to be elevated in the serum of ibrutinib-refractory CLL patients. Functional studies showed that targeting the IL-16/CD9 axis using neutralizing antibodies or CD9-binding peptides restored sensitivity to BTK inhibitors and R-CHOP chemotherapy in MZL, mantle cell lymphoma, and diffuse large B-cell lymphoma models. These findings reveal a novel, targetable resistance mechanism with potential therapeutic implications for overcoming BTK inhibitor resistance in B-cell lymphomas.

cancer biology↗

Characterization of a novel humanized heavy chain antibody targeting endogenous retroviruses with anti-lymphoma activity

Lymphomas continue to pose therapeutic challenges, with a considerable portion of patients facing refractory disease. This study focuses on Diffuse Large B-cell Lymphoma (DLBCL), the most prevalent lymphoma type. Within the human genome, transposable elements (TEs), particularly Human Endogenous Retroviruses (HERVs), constitute a significant yet understudied portion. Among HERVs, the HERV-K family, specifically HERV-K113 and HERV-K115, has intact open reading frames. Epigenetic regulation tightly controls HERV expression, and aberrant expression has been observed in various cancers, including lymphomas. This research investigates the potential of HERV-K as a therapeutic target in DLBCL. The study encompasses comprehensive methods, including RNA extraction, PCR detection, flow cytometry, immunoblotting, peptide prediction, phage display, surface plasmon resonance, ELISA, antibody-dependent cell-mediated cytotoxicity, internalization assays, and bioinformatic analysis. Results reveal the presence and expression of HERVs in lymphoma patients and cell lines, with the HERV-K envelope protein identified as a crucial contributor to lymphoma cell growth. Moreover, the study identifies immunogenic regions of HERV-K, leading to the development of a humanized camelid nanobody (FF-01) with potential therapeutic applications. Furthermore, bioinformatic analysis differentiates DLBCL subgroups based on TE expression, providing insights into prognostic variations. Patients with high HERV-K113 expression show activation of pathways related to antiviral responses, suggesting a viral mimicry state. In conclusion, the study highlights the clinical relevance of HERVs in lymphomas, proposing them as novel therapeutic targets. The newly developed nanobody FF-01 demonstrates anti-lymphoma activity through antibody-dependent cellular cytotoxicity and internalization. This research opens avenues for exploring endogenous retroviruses as targets for immunotherapy in lymphomas, showcasing the potential of FF-01 as a promising candidate for further investigation.

cancer biology↗

PI3Kδ activation, IL6 over-expression, and CD37 loss cause resistance to the targeting of CD37-positive lymphomas with the antibody-drug conjugate naratuximab emtansine

PurposeThe transmembrane protein CD37 is expressed almost exclusively in lymphoid tissues, with the highest abundance in mature B cells. CD37-directed antibody- and, more recently, cellular-based approaches have shown preclinical and promising early clinical activity. Naratuximab emtansine (Debio 1562, IMGN529) is an antibodydrug conjugate (ADC) that incorporates an anti-CD37 monoclonal antibody conjugated to the maytansinoid DM1 as payload. Naratuximab emtansine has shown activity as a single agent and in combination with the anti-CD20 monoclonal antibody rituximab in B cell lymphoma patients. Experimental DesignWe assessed the activity of naratuximab emtansine using in vitro models of lymphomas, correlated its activity with CD37 expression levels, characterized two resistance mechanisms to the ADC, and identified combination partners providing synergy. ResultsThe anti-tumor activity of naratuximab emtansine was tested in 54 lymphoma cell lines alongside its free payload. The median IC50 of naratuximab emtansine was 780 pM, and the activity, primarily cytotoxic, was more potent in B than in T cell lymphoma cell lines. In the subgroup of cell lines derived from B cell lymphoma, there was some correlation between sensitivity to DM1 and sensitivity to naratuximab emtansine (r=0.28, P = 0.06). After prolonged exposure to the ADC, one diffuse large B cell lymphoma (DLBCL) cell line developed resistance to the ADC due to the biallelic loss of the CD37 gene. After CD37 loss, we also observed upregulation of IL6 (IL-6) and other transcripts from MYD88/IL6-signaling. Recombinant IL6 led to resistance to naratuximab emtansine, while the anti-IL6 antibody tocilizumab improved the cytotoxic activity of the ADC in CD37-positive cells. In a second model, resistance was sustained by an activating mutation in the PIK3CD gene, associated with increased sensitivity to PI3K{delta} inhibition and a switch from functional dependence on the anti-apoptotic protein MCL1 to reliance on BCL2. The addition of idelalisib or venetoclax to naratuximab emtansine overcame resistance to the ADC in the resistant derivative while also improving the cytotoxic activity of the ADC in the parental cells. ConclusionsTargeting B cell lymphoma with the CD37 targeting ADC naratuximab emtansine showed vigorous anti-tumor activity as a single agent, which was also observed in models bearing genetic lesions associated with inferior outcomes, such as MYC translocations and TP53 inactivation or resistance to R-CHOP. Resistance DLBCL models identified active combinations of naratuximab emtansine with drugs targeting IL6, PI3K{delta}, and BCL2. Despite notable progress in recent decades, we still face challenges in achieving a cure for a substantial number of lymphoma patients (1,2). A pertinent example is diffuse large B cell lymphoma (DLBCL), the most prevalent type of lymphoma (3). More than half of DLBCL patients can achieve remission, but around 40% of them experience refractory disease or relapse following an initial positive response (3). Regrettably, the prognosis for many of these cases remains unsatisfactory despite introducing the most recent antibody-based or cellular therapies (3,4), underscoring the importance of innovating new therapeutic strategies and gaining insights into the mechanisms of therapy resistance. CD37 is a transmembrane glycoprotein belonging to the tetraspanin family, primarily expressed on the surface of immune cells, principally in mature B cells but also, at lower levels, in T cells, macrophages/monocytes, granulocytes and dendritic cells (5) (6-8). CD37 plays a crucial role in various immune functions, including B cell activation, proliferation, and signaling, although its precise role still needs to be fully elucidated. CD37 interacts with multiple molecules, including SYK, LYN, CD19, CD22, PI3K{delta}, PI3K{gamma}, and different integrins, among others (6-8). In mice, the lack of CD37 is paired with reduced T cell-dependent antibody-secreting cells and memory B cells, apparently due to the loss of CD37-mediated clustering of 4{beta}1 integrins (VLA-4) on germinal center B cells and decreased downstream activation of PI3K/AKT signaling and cell survival (5). Reflecting the expression pattern observed in normal lymphocytes, CD37 exhibits elevated expression in all mature B-cell lymphoid neoplasms, including most lymphoma subtypes, and absence in early progenitor cells or terminally differentiated plasma cells (6,8-14). In DLBCL, CD37 expression has been reported between 40% and 90% of cases across multiple studies performed using different antibodies (10,14-16). CD37-directed antibody- and, more recently, cellular-based approaches have shown preclinical (7,10-14,17-23) and early promising clinical activity (24-32). Among the CD37-targeting agents, naratuximab emtansine (Debio 1562, IMGN529) is an antibody-drug conjugate (ADC) that incorporates the anti-CD37 humanized IgG1 monoclonal antibody K7153A conjugated to the maytansinoid DM1, as payload, via the thioether linker, N-succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) (10). Based on the initial in vitro and in vivo evidence of anti-tumor activity in lymphoma and chronic lymphocytic leukemia (CLL) (7,10), naratuximab emtansine entered the clinical evaluation as a single agent. The phase 1 study exploring naratuximab emtansine enrolled 39 patients with relapsed/refractory B cell lymphoma (27). The overall response rate (ORR) was 13% across all patients and 22% in DLBCL patients, including the only observed complete remission (CR) (27). In preliminary results of a phase 2 trial exploring the combination of naratuximab emtansine with the anti-CD20 monoclonal antibody rituximab (18), based on positive preclinical data (18), the ORR was 45% in 76 patients with DLBCL with 24 CRs (32%), 57% in 14 patients with follicular lymphoma (five CR), 50% in four MCL patients (2 CR) (31). Here, we studied the pattern of activity of naratuximab emtansine across a large panel of cell lines derived from DLBCL and other lymphoma subtypes and characterized two resistance mechanisms to the ADC.

cancer biology↗

Targeting CD19-positive lymphomas with the antibody-drug conjugate (ADC) loncastuximab tesirine: preclinical evidence as single agent and as combinatorial approach

PurposeAntibody-drug conjugates (ADCs) represent one of the most successful therapeutic approaches introduced in clinical practice in the last years. Loncastuximab tesirine (ADCT-402) is a CD19 targeting ADC, in which the antibody is conjugated through a protease cleavable dipeptide linker to a pyrrolobenzodiazepine (PBD) dimer warhead (SG3199). Based on the results of a phase 2 study, loncastuximab tesirine was recently approved for adult patients with relapsed/refractory large B-cell lymphoma. Experimental DesignWe assessed the activity of loncastuximab tesirine in in vitro and in vivo models of lymphomas, correlated its activity with CD19 expression levels and identified combination partners providing synergy with loncastuximab tesirine. ResultsLoncastuximab tesirine was tested across 60 lymphoma cell lines. Loncastuximab tesirine has strong cytotoxic activity in B-cell lymphoma cell lines and the in vitro activity is correlated with CD19 expression level and with intrinsic sensitivity of cell lines to the ADCs warhead. Loncastuximab tesirine was more potent than other anti-CD19 ADCs (coltuximab ravtansine, huB4-DGN462), albeit the pattern of activity across cell lines was correlated. Loncastuximab tesirine activity also largely correlated with cell line sensitivity to R-CHOP. Combinatorial in vitro and in vivo experiments identified the benefit of adding loncastuximab tesirine to other agents, especially BCL2 and PI3K inhibitors. ConclusionsOur data support the further development of loncastuximab tesirine as single agent and in combination for patients affected by mature B-cell neoplasms. The results also highlight the importance of CD19 expression, and the existence of lymphoma populations characterized by resistance to multiple therapies.

cancer biology↗

ERBB4-mediated signaling is a mediator of resistance to BTK and PI3K inhibitors in B cell lymphoid neoplasms

BTK and PI3K inhibitors are among the drugs approved for the treatment of patients with lymphoid neoplasms. Although active, their ability to lead as single agents to long-lasting complete remission is rather limited especially in the lymphoma setting. This indicates that tumor cells often develop resistance to the drugs. Here, we show that the overexpression of ERBB4 and its ligands represents a modality for B cell neoplastic cells to bypass the anti-tumor activity of BTK and PI3K inhibitors and that targeted pharmacological interventions can restore sensitivity to the small molecules. We started from a marginal zone lymphoma (MZL) cell line, Karpas-1718, kept under prolonged exposure to the PI3K{delta} inhibitor idelalisib until acquisition of resistance, or with no drug. Cells underwent transcriptome, miRNA and methylation profiling, whole exome sequencing, and pharmacological screening which led to the identification of the overexpression of ERBB4 and its ligands HBEGF and NRG2 in the resistant cells. Cellular and genetic experiments demonstrated the involvement of this axis in blocking the anti-tumor activity of various BTK and PI3K inhibitors, currently used in the clinical setting. Addition of recombinant HBEGF induced resistance to BTK and PI3K inhibitors in parental cells but also in additional lymphoma models. Combination with the ERBB inhibitor lapatinib was beneficial in resistant cells and in other lymphoma models already expressing the identified resistance factors. Multi-omics analysis underlined that an epigenetic reprogramming affected the expression of the resistance-related factors, and pretreatment with demethylating agents or EZH2 inhibitors overcame the resistance. Resistance factors were shown to be expressed in clinical samples, further extending the findings of the study. In conclusions, we identified a novel ERBB4-driven mechanism of resistance to BTK and PI3K inhibitors and treatments that appear to overcome it. Key pointsO_LIA mechanism of secondary resistance to the PI3K{delta} and BTK inhibitors in B cell neoplasms driven by secreted factors. C_LIO_LIResistance can be reverted by targeting ERBB signaling. C_LI

cancer biology↗

Differential genomic and transcriptomic events associated with high-grade transformation of Chronic Lymphocytic Leukemia

The transformation of chronic lymphocytic leukemia (CLL) to high-grade diffuse large B-cell lymphoma (DLBCL), also called Richters Syndrome (RS), is a rare cancer with dismal prognosis. Drug discovery for RS is hampered by the lack of suitable experimental models, and effective therapies remain elusive rendering RS an area of high unmet clinical need. We performed whole genome sequencing (WGS) to interrogate paired CLL and RS samples from 17 patients enrolled in a prospective multicenter Phase 2 clinical trial (CHOP-OR) and we found that subclones affected by mutations in MAPK and PI3K pathways show a high expansion probability during transformation. We also demonstrate for the first time that non-coding mutation clusters in a PAX5 enhancer, situated 330kb upstream from the transcription initiation site, correlate with transformation. Finally, we confirm our findings by employing targeted DNA sequencing (TGS) and RNA expression profiling on an extended cohort of 38 patients.\n\nStatement of significanceThrough integrated analysis of WGS, TGS and RNA expression data, we identified drivers of transformation not previously implicated in RS, which can be targeted therapeutically and tested in the clinic. Our results have informed the design of a new clinical platform study, which is now open to recruitment in the UK.

genomics↗

HSCs contribute actively to native multilineage hematopoiesis but with reduced differentiation capacity upon aging

A hallmark of adult hematopoiesis is the continuous replacement of blood cells with limited lifespans. It is well established that adult hematopoietic stem cells (HSCs) are active contributors to these processes after transplantation, yet their role in native hematopoiesis has recently been called into question. Here, we use inducible lineage tracing from genetically marked adult HSCs to explore their roles in the steady state. We show that adult HSCs contribute robustly to all lineages via intermediate progenitor cells, but with neglible production of hematopoietic cells with a known fetal origin. We further reveal that the timing for regeneration of distinct blood lineages varies substantially. Finally, HSC contribution to multilineage hematopoiesis in aged animals declines with increasing age. Therefore, while HSCs are active contributors to native adult hematopoiesis, it appears that the numerical increase of HSCs is a physiologically relevant compensatory mechanism to account for a reduced differentiation capacity with age.

developmental biology↗

Nanoscale investigation in 3D scaffolds of cell-material interactions for tissue-engineering

Cell fate is largely determined by interactions that occur at the interface between cells and their surrounding microenvironment. For this reason, especially in the field of cell- and tissue-engineering, there is a growing interest in developing characterization techniques that allow a deep evaluation of cell-material interaction at the nanoscale, particularly focusing on cell adhesion processes. While for 2D culturing systems a consolidated series of tools already satisfy this need, in 3D environments, more closely recapitulating complex in vivo structures, there is still a lack of procedure furthering the comprehension of cell-material interactions. Here, we report for the first time the use of a SEM/FIB system for the characterization of cellular adhesion in 3D scaffolds fabricated by means of different techniques. Our results clearly show the capability of the developed approach to finely resolve both scaffold-cells interface and nanometer scale features of cell bodies involved in the upregulation of cellular behavior. These results are relevant for studying cellular guidance strategies and for the consequent design of more efficient cell-instructive platforms for tissue-engineering applications as well as for in vitro 3D models.

bioengineering↗