Biology subjects

Guerra, G.

Publications and source records attributed to Guerra, G..

4 recordsLinked to original sources

bioRxiv2026

HKDC1 contributes to aberrant lysosome-mitochondria contact in Niemann-Pick disease type C

Niemann-Pick disease type C (NPC) is a neurovisceral lysosomal storage disorder comprising two clinically indistinguishable but genetically distinct subtypes caused by mutations in NPC1, or NPC2. The specific impact of each deficiency on cellular homeostasis remains poorly defined due to the phenotypic heterogeneity of patient-derived models and a lack of isogenic platforms for comparative study. Here we established isogenic ARPE19 models of NPC1 and NPC2 deficiency that faithfully recapitulate hallmark pathologies, including homogeneous lysosomal expansion and lipid sequestration. Direct comparison of these isogenic lines revealed a fundamental divergence in organelle crosstalk: while both genotypes exhibit comparable lipid accumulation, expanded mitochondria-lysosome contact sites (MLCs) are observed exclusively in NPC1-/- cells. Using StARD3-targeted proximity labelling and quantitative proteomics, we identified the mitochondrial protein HKDC1 as an MLC regulator. We demonstrate that HKDC1 is markedly upregulated in NPC1-/- cells and that its overexpression drives MLC expansion in wild-type cells. Thus our study uncovers a homeostatic role for HKDC1-mediated organelle remodelling and demonstrates the power of isogenic modelling for identifying novel regulators of organelle architecture and potential therapeutic targets.

cell biology↗

bioRxiv2024

Tumoral hypoxic extracellular vesicles create a protective microenvironment for triple-negative breast cancer

The highly metastatic triple-negative breast cancer (TNBC) relies on the tumor microenvironment (TME) to maintain phenotypic heterogeneity and progression. Extracellular vesicles from hypoxic TNBC (EVh) have been previously shown to facilitate tumoral invasion; however, their function in the tumor microenvironment remains unclear. We used a novel method to investigate the TME in vitro called multicellular circulating co-culture, to characterize how EVh interferes with tumoral and endothelial cells, fibroblasts, monocytes and macrophages. EVh promoted monocyte differentiation to M2-like macrophages and inhibited macrophage-derived phagocytosis in endothelial and tumoral cells. The protection of endothelial, tumoral and stromal cellular integrity by EVh increased pro-tumoral and pro-angiogenic signaling, collagen matrix synthesis and showed a potential differentiation to cancer-associated fibroblasts. Our findings highlight the critical role of EVh in protecting tumor cells, indicating its cooperation towards a protective TME, which was demonstrated by the multicellular circulating co-culture and conventional co-culture protocols. These findings lead to an adequate system with potential for investigating other tumor-related processes, including circulating tumor cells and metastasis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/621519v3_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@4ff8a0org.highwire.dtl.DTLVardef@4bf15corg.highwire.dtl.DTLVardef@1d2f105org.highwire.dtl.DTLVardef@1cd8346_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

Targeting SCD triggers lipotoxicity of cancer cells and enhances anti-tumor immunity in breast cancer brain metastasis mouse models

Breast cancer brain metastases (BCBM) are a significant cause of mortality and are incurable. Thus, identifying BCBM targets that reduce morbidity and mortality is critical. BCBM upregulate Stearoyl-CoA Desaturase (SCD), an enzyme that catalyzes the synthesis of monounsaturated fatty acids, suggesting a potential metabolic vulnerability of BCBM. In this study, we tested the effect of a brain-penetrant clinical-stage inhibitor of SCD (SCDi), on breast cancer cells and mouse models of BCBM. Lipidomics, qPCR, and western blot were used to study the in vitro effects of SCDi. Single-cell RNA sequencing was used to explore the effects of SCDi on cancer and immune cells in a BCBM mouse model. Pharmacological inhibition of SCD markedly reshaped the lipidome of breast cancer cells and resulted in endoplasmic reticulum stress, DNA damage, loss of DNA damage repair, and cytotoxicity. Importantly, SCDi alone or combined with a PARP inhibitor prolonged the survival of BCBM-bearing mice. When tested in a syngeneic mouse model of BCBM, scRNAseq revealed that pharmacological inhibition of SCD enhanced antigen presentation by dendritic cells, was associated with a higher interferon signaling, increased the infiltration of cytotoxic T cells, and decreased the proportion of exhausted T cells and regulatory T cells in the tumor microenvironment (TME). Additionally, pharmacological inhibition of SCD decreased engagement of immunosuppressive pathways, including the PD-1:PD-L1/PD-L2 and PVR/TIGIT axes. These findings suggest that SCD inhibition could be an effective strategy to intrinsically reduce tumor growth and reprogram anti-tumor immunity in the brain microenvironment to treat BCBM.

cancer biology↗

bioRxiv2022

Adipocyte differentiation of 3T3-L1 cells under TAF, TDF and INSTIs selective challenge: an in vitro model.

Integrase strand transfer inhibitors (INSTI) are a recently available class of antiretroviral therapy (ART) medications with a good tolerability profile and a high genetic barrier to HIV drug resistance. However, several studies report more significant weight gain among persons receiving INSTI-based ART regimens for initial therapy compared to protease inhibitors (PIs) and nucleoside reverse transcriptase inhibitors (NNRTI)-based regimens. In our experimental setting, we used the in vitro model of adipogenesis of 3T3-L1 cells to investigate the effects of the NRTIs tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), alone or in combination with four integrase strand transfer inhibitors: raltegravir (RAL), elvitegravir (ELV), dolutegravir (DTG) and bictegravir (BIC) on adipose differentiation. In addition, protein expression levels of PPAR{gamma} and C/EBP, and the intracellular lipid accumulation by Red Oil staining, were used to monitor adipocyte differentiation. Compared to control, RAL, ELV, DTG, and BIC were all able to increase adipogenesis, being in this, RAL and ELV more efficient. On the other hand, TAF and TDF inhibited adipogenesis. Moreover, when used in combination with the other INSTI molecules, TAF and TDF were able to reduce the adipogenic effects of all four drugs. This ability was more evident when TAF was used in combination with DTG and BIC. All these data suggest that TAF and TDF have an inhibitory effect on adipogenesis in vitro and that they could also effectively counteract the increased adipogenesis caused by the treatment with INSTIs. Finally, to evaluate if the 3T3-L1 cell could express fibroblast-like features following INSTIs treatment, we evaluated the immunohistochemical expression of ER-TR7, a well-known fibroblastic marker. This last assay showed that treatment with INSTIs increased the expression of ER-TR7 compared to control and to cells treated with TAF o TDF. In conclusion, our experimental data support the evidence that in vitro challenge of 3T3-L1 cells with INSTIs is able to increase adipocytic differentiation and to drive a number of these cells toward the expression of fibroblastic features, with a different degree according to the various drugs used, while TAF and TDF have an antagonistic role on this phenomenon.

pharmacology and toxicology↗