Biology subjects

Piccio, L.

Publications and source records attributed to Piccio, L..

7 recordsLinked to original sources

bioRxiv2026

TriPort tangential flow filtration: a lab-assembled system for EV isolation across diverse cell-culture sources

Tangential flow filtration (TFF) is an effective method for scalable EV isolation. Here, we describe and validate a reference protocol for TriPort-TFF, a laboratory-assembled TFF system featuring a three- port reservoir design enabling sample circulation, retentate return, and diafiltration. Constructed from individually sourced, commercially available components with detailed assembly and operating parameters, TriPort-TFF can be built at a lower cost than commercially integrated TFF platforms. We evaluated the system using conditioned media (CM) from human MDM cultured with EV-depleted human serum, human cerebral organoids in serum-free medium, and mouse BMDM cultured with EV-depleted foetal bovine serum (FBS) unstimulated or LPS-stimulated. The system reproducibly isolated EVs from all three sources, and biological replicates of BMDM showed distinct proteomic clusters between LPS-stimulated and unstimulated conditions. The requirement for subsequent size-exclusion chromatography (SEC) after TFF depended on the sample serum-presence. In serum-containing CM, TFF alone co-concentrated serum proteins alongside EVs, subsequent SEC improved the particle-to- protein ratio, reduced inter-replicate variability and improved proteomic depth. TFF alone in serum- free organoid CM already yielded higher particle-to-protein ratios than TFF-only preparations from serum-containing CM, with SEC further improving this ratio. TriPort-TFF offers an accessible system for EV-isolation that can be combined with SEC for diverse sample types.

cell biology↗

bioRxiv2024

High fat low carbohydrate diet is linked to protection against CNS autoimmunity

Multiple sclerosis (MS) is a common central nervous system (CNS) autoimmune disease, and diets and nutrients are emerging as critical contributing factors. However, a comprehensive understanding of their impacts and the underlying mechanisms involved is lacking. Harnessing state-of-the-art nutritional geometry analytical methods, we first revealed that globally, increased carbohydrate supply was associated with increased MS disease burden, while fat supply had an opposite effect. Furthermore, in a preclinical MS mouse model, experimental autoimmune encephalomyelitis (EAE), we found that an isocaloric diet high in carbohydrate aggravated EAE, while a diet enriched in fat was fully protective. This was reflected by reduced neuroinflammation and skewing towards anti-inflammatory phenotypes, which involved transcriptomic, epigenetic and immunometabolic changes. We showcased that manipulating diets is a potentially efficient and cost-effective approach to prevent and/or ameliorate EAE. This exhibits translational potentials for intervention/prevention of MS and possibly other autoimmune diseases.

immunology↗

bioRxiv2023

Insight into the gut virome in patients with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune condition associated with dysbiosis in the bacterial element of microbiome, yet limited information exists regarding dysbiosis in the virome. In this study, we examined the virome in 20 relapsing-remitting MS (RRMS) patients and 22 healthy controls (HC). We extracted virus-like particles (VLP) genomic DNA through sequential filtration, followed by deep metagenomic sequencing approaches with and without multiple displacement amplification (MDA). We found significantly lower diversity in the gut virome of RRMS patients relative to HC, consistent across both sequencing methods. MDA method identified reduced relative abundance of Microviridae and Myoviridae bacteriophage, and eukaryotic virus such as Herpesviridae and Phycodnaviridae in RRMS patients compared to HC. Non-MDA methods showed reduction in relative abundance of Siphoviridae bacteriophage and eukaryotic viruses such as Ackermannviridae, Demerecviridae, Dicistroviridae, Herelleviridae, Mesnidovirineae in RRMS patients. Cluster analysis revealed that the whole virome family was dominated by Podoviridae and Siphoviridae clusters. Comparing dietary metadata between these clusters, RRMS patients in the Siphoviridae-dominated Cluster B showed significantly higher consumption of refined grains and salad dressings compared to those in the Podoviridae-dominated Cluster A. Correlation analysis between gut viruses and bacteria demonstrated that Siphoviridae exhibited positive correlations with many different bacterial genera. Conversely, Microviridae displayed negative correlations with many different bacterial genera. These findings underscore the alterations in viral diversity and taxonomic composition of the gut virome in RRMS patients. Our study represents the first step in understanding the gut virome in MS patients, providing a groundwork for future research on the role of the gut virome in the context of MS.

microbiology↗

bioRxiv2022

Systematic characterization of brain cellular crosstalk signaling networks in Alzheimer's disease reveals a novel role for SEMA6D in TREM2-dependent microglial activation

Cellular crosstalk, mediated by membrane receptors and their ligands, is crucial for brain homeostasis and can contribute to neurodegenerative diseases such as Alzheimers disease (AD). To discover crosstalk dysregulations in AD, we reconstructed crosstalk networks from single-nucleus transcriptional profiles from 67 clinically and neuropathologically well-characterized controls and AD brain donors. We predicted a significant role for TREM2 and additional AD risk genes mediating neuron-microglia crosstalk in AD. The gene sub-network mediating SEMA6D-TREM2 crosstalk is activated near A{beta} plaques and SEMA6D-expressing cells and is disrupted in late AD stages. Using CRISPR-modified human induced pluripotent stem cell-derived microglia, we demonstrated that SEMA6D induces microglial activation in a TREM2-dependent manner. In summary, we demonstrate that characterizing cellular crosstalk networks can yield novel insights into AD biology. One Sentence SummaryWe investigate cell-to-cell communication in Alzheimers disease to characterize disease biology and suggest new avenues for therapeutic intervention.

neuroscience↗

bioRxiv2022

Early microglial response, myelin deterioration and lethality in mice deficient for very long chain ceramide synthesis in oligodendrocytes

The sphingolipids galactosylceramide (GalCer), sulfatide (ST) and sphingomyelin (SM) are essential for myelin stability and function. GalCer and ST are synthesized mostly from C22-C24 ceramides, generated by Ceramide Synthase 2 (CerS2). To clarify the requirement for C22-C24 sphingolipid synthesis in myelin lipid biosynthesis and stability, we generated mice lacking CerS2 specifically in myelinating cells (CerS2{Delta}O/{Delta}O). At 6 weeks of age, normal-appearing myelin had formed in CerS2{Delta}O/{Delta}O mice, however there was a reduction in myelin thickness and the percentage of myelinated axons. Pronounced loss of C22-C24 sphingolipids in myelin of CerS2{Delta}O/{Delta}O mice was compensated by greatly increased levels of C18 sphingolipids. A distinct microglial population expressing high levels of activation and phagocytic markers such as CD64, CD11c, MHC class II, and CD68 was apparent at 6 weeks of age in CerS2{Delta}O/{Delta}O mice, and had increased by 10 weeks. Increased staining for denatured myelin basic protein was also apparent in 6-week-old CerS2{Delta}O/{Delta}O mice. By 16 weeks, CerS2{Delta}O/{Delta}O mice showed pronounced myelin atrophy, motor deficits, and axon beading, a hallmark of axon stress. 90% of CerS2{Delta}O/{Delta}O mice died between 16 and 26 weeks of age. This study highlights the importance of sphingolipid acyl chain length for the structural integrity of myelin, demonstrating how a modest reduction in lipid chain length causes exposure of a denatured myelin protein epitope and expansion of phagocytic microglia, followed by axon pathology, myelin degeneration, and motor deficits. Understanding the molecular trigger for microglial activation should aid the development of therapeutics for demyelinating and neurodegenerative diseases. Main PointsO_LIOligodendrocytes lacking CerS2 produce myelin using sphingolipids with C16/C18 instead of C22/C24 N-acyl chains C_LIO_LIC22/C24 myelin sphingolipids are essential for myelin stability, microglial quiescence, and survival beyond young adulthood C_LI Table of Contents Image O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=172 SRC="FIGDIR/small/493337v2_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@1125540org.highwire.dtl.DTLVardef@9aeebdorg.highwire.dtl.DTLVardef@1afbeb4org.highwire.dtl.DTLVardef@11156c2_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2019

Dietary intake regulates the circulating inflammatory monocyte pool

Caloric restriction is known to improve inflammatory and autoimmune diseases. However, the mechanisms by which reduced caloric intake modulates inflammation are poorly understood. Here we show that short-term fasting reduced monocyte metabolic and inflammatory activity and drastically reduced the number of circulating monocytes. Regulation of peripheral monocyte numbers was dependent on dietary glucose and protein levels. Specifically, we found that activation of the low-energy sensor 5-AMP-activated protein kinase (AMPK) in hepatocytes and suppression of systemic CCL2 production by peroxisome proliferator-activator receptor alpha (PPAR) reduced monocyte mobilization from the bone marrow. Importantly, while caloric restriction improves chronic inflammatory diseases, fasting did not compromise monocyte emergency mobilization during acute infectious inflammation and tissue repair. These results reveal that caloric intake and liver energy sensors dictate the blood and tissue immune tone and link dietary habits to inflammatory disease outcome.\n\nHighlightsO_LIFasting reduces the numbers of peripheral pro-inflammatory monocytes in healthy humans and mice.\nC_LIO_LIA hepatic AMPK-PPAR energy-sensing axis controls homeostatic monocyte numbers via regulation of steady-state CCL2 production.\nC_LIO_LIFasting reduces monocyte metabolic and inflammatory activity.\nC_LIO_LIFasting improves chronic inflammatory diseases but does not compromise monocyte emergency mobilization during acute infectious inflammation and tissue repair.\nC_LI

immunology↗

bioRxiv2018

The MS4A gene cluster is a key regulator of soluble TREM2 and Alzheimer disease risk

Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) levels in the cerebrospinal fluid (CSF) have been associated with Alzheimer disease (AD) status. TREM2 plays a critical role in microglial activation, survival, and phagocytosis; however, the pathophysiological role of sTREM2 in AD is not well understood. Understanding the role of sTREM2 in AD may help reveal biological mechanisms underlying AD and identify novel therapeutic targets. We performed a genome-wide association study (GWAS) to identify genetic modifiers of CSF sTREM2 levels. Common variants in the membrane-spanning 4-domains subfamily A (MS4A) gene region were associated with higher CSF sTREM2 levels (rs1582763; P = 1.15x10-15) and replicated in independent datasets. The variants associated with increased levels of sTREM2 are also associated with reduced AD risk and delayed age-at-onset. Rs1582763 influences expression of MS4A4A and MS4A6A in multiple tissues, suggesting that one or both of these genes are important for regulating sTREM2. MS4A genes encode transmembrane proteins that may play a role in intracellular protein trafficking in microglia. We used human macrophages to begin to test the relationship between MS4A4A and TREM2 and found that they co-localize intracellularly and that antibody-mediated targeting of MS4A4A reduces sTREM2. Thus, genetic, molecular, and cellular findings suggest that MS4A4A regulates sTREM2. These findings also provide a mechanistic explanation of the original GWAS signal in the MS4A locus for AD risk and indicate that TREM2 is involved in sporadic AD risk in general, not only in TREM2 risk-variant carriers.

genomics↗