Biology subjects

Raimondi, M. T.

Publications and source records attributed to Raimondi, M. T..

4 recordsLinked to original sources

bioRxiv2025

Engineering macrophage responses through 3D scaffold microarchitecture

Biomaterial implantation in living organisms triggers a physiological response known as foreign body reaction, leading to the recruitment of macrophages, that can polarize either into a pro-inflammatory (M1) or an anti-inflammatory (M2) phenotype. Currently, there is growing interest in tailoring the physical properties of tissues and biomaterials to promote efficient tissue regeneration. Tridimensionality can profoundly influence macrophage behaviour; however, there is no clear consensus on the underlying mechanisms. 3D microstructures may play a crucial role in modulating immune cells, promoting anti-inflammatory responses, and supporting effective tissue repair and regeneration. In this study, we used two-photon polymerization to fabricate 3D scaffolds with large pores, measuring 50x50x20 m3, and small pores, measuring 15x15x15 m3. Both microstructures effectively influenced macrophage cytoskeletal organization and cellular metabolic activity. Notably, they were not sufficient to induce spontaneous macrophage polarization, indicating that they are intrinsically immunologically inert. When combined with chemical stimulation, as typically occurs in vivo, they elicited distinct responses. Specifically, as evidenced by the slight upregulation of the Arg1 marker, large pore sizes promoted an anti-inflammatory phenotype. Conversely, iNOS expression measurements indicated that small pores, which impose spatial constraints on macrophages, favoured a massive pro-inflammatory state. Our results demonstrate that 3D microstructures are versatile tools for multiple applications. Their precisely tunable architecture enables fine control over macrophage behaviour and immunomodulation, opening new avenues both for tissue engineering, by preventing fibrosis and promoting anti-inflammatory and pro-regenerative responses in vivo, and for the development of in vitro platforms to model inflamed tissues for screening anti-inflammatory drugs.

bioengineering↗

bioRxiv2024

The molecular basis of the anticancer effect of statins

Statins, one of the most used class of cardiovascular drugs with the primary function of reducing blood cholesterol levels, exert their effect by inhibiting the enzyme HMG-CoA reductase, the key player in cholesterol biosynthesis. While the primary indication for statins is the prevention of cardiovascular diseases, there has been growing interest in their potential anticancer effects. However, the current evidence on these effects is largely based on epidemiological observations and preclinical research, not yet substantiated by knowledge of the mechanisms behind it. Here we show that statins have an anticancer effect as they exploit the principle of Synthetic Lethality, a concept in which the combination of two non-lethal genetic or molecular events results in cell death or impairment. When either of these events occurs alone, it is not lethal, but when they happen coupled, they create a lethal condition for the cell. In this work we report that statins emerged from a computational data analysis that we performed on approximately 37,000 synthetic lethality couples. We performed this analysis to select repurposable drugs that could target genes involved in Synthetic Lethality couples with metastatic genes. We validated our discovery in vitro by drug tests performed on cell lines derived from cancers of the breast, ovary, and cervix. Our data-driven drug repurposing strategy allowed us to understand the molecular basis of the anticancer effect of statins, a discovery which can be directly translated into practical clinical applications in oncology.

cancer biology↗

bioRxiv2022

Microlenses fabricated by two-photon laser polymerisation for intravital cell imaging with non-linear excitation microscopy

Non-linear excitation microscopy offers several advantages for in-vivo imaging compared to conventional confocal techniques. However, tissue penetration can still be an issue due to scattering and spherical aberrations induced on focused beams by the tissue. The use of low numerical aperture objectives to pass through the outer layers of the skin, together with high dioptric power microlenses implanted in-vivo close to the observation volume, can be beneficial to the reduction of optical aberrations. Here, we develop and test on fibroblast cell culture plano-convex microlenses to be used for non-linear imaging of biological tissue. The microlenses can be used as single lenses or multiplexed in an array. A thorough test of the lenses wavefront is reported together with the modulation transfer function and wavefront profile. We could retrieve magnified fluorescence images through the microlenses coupled to commercial confocal and two-photon excitation scanning microscopes. The signal-to-noise ratio of the images is not substantially affected by the use of the microlenses and the magnification can be adjusted by changing the relative position of the microlens array to the microscope objective and the immersion medium. These results are opening the way to the application of implanted micro-optics for optical in-vivo inspection of biological processes.

bioengineering↗

bioRxiv2020

Intracellular label-free detection of mesenchymal stem cell metabolism within a perivascular niche-on-a-chip

The stem cell niche at the perivascular space in human tissue plays a pivotal role in dictating the overall fate of stem cells within it. Mesenchymal stem cells (MSCs), in particular, experience influential microenvironmental conditions, which induce specific metabolic profiles that affect processes such as cell differentiation and dysregulation of the immunomodulatory funtion. Reports focusing specifically on the metabolic status of MSCs under the effect of pathophysiological stimuli - in terms of flow velocities, shear stresses or oxygen tension - do not model heterogenous gradients, highlighting the need of more advanced models reproducing the metabolic niche. Organ-on-a-chip technology offers the most advanced tools for stem cell niche modelling thus allowing for controlled dynamic culture conditions while profiling tunable oxygen tension gradients. However, current systems for live cell detection of metabolic activity inside microfluidic devices require the integration of microsensors that allow for extracellular measurments only, giving innacurate and indirect information about the metabolic state of cells. Here, we present a metabolic toolbox coupling a miniatuirzed in vitro system for human-MSCs dynamic culture, that mimics microenvironmental conditions of the perivascular niche, with high-resolution imaging of intracellular metabolism. Using Fluorescence Lifetime Imaging Microscopy (FLIM) we monitor the spatial metabolic machinery and correlate it with experimentally validated intracellular oxygen concentration after designing the oxygen tension decay along the fluidic chamber by in silico models prediction. Our platform allows for the subjection of a metabolic profile to MSCs, mimicking the physiological niche in space and time, and its real-time monitoring representing a functional tool for modelling perivascular niches, relevant diseases and metabolic-related uptake of pharmaceuticals.

bioengineering↗