Intranasally Administered MSC-Derived Extracellular Vesicles Reverse Cisplatin-Induced Cognitive Impairment

Neurotoxic side effects of chemotherapy include deficits in attention, memory, and executive functioning. Currently, there are no FDA-approved therapies. In mice, cisplatin causes long-term cognitive deficits, white matter damage, mitochondrial dysfunction, and loss of synaptic integrity. We hypothesized that MSC-derived small extracellular vesicles (sEVs) could restore cisplatin-induced cognitive impairments and brain damage. Animals were injected with cisplatin intraperitoneally and treated with MSC-derived sEVs intranasally 48 and 96 h after the last cisplatin injection. The puzzle box test (PBT) and the novel object place recognition test (NOPRT) were used to determine cognitive deficits. Synaptosomal mitochondrial morphology was analyzed by transmission electron microscopy. Immunohistochemistry using antibodies against synaptophysin and PSD95 was applied to assess synaptic loss. Black-Gold II staining was used to quantify white matter integrity. Our data show that sEVs enter the brain in 30 min and reverse the cisplatin-induced deficits in executive functioning and working and spatial memory. Abnormalities in mitochondrial morphology, loss of white matter, and synaptic integrity in the hippocampus were restored as well. Transcriptomic analysis revealed upregulation of regenerative functions after treatment with sEVs, pointing to a possible role of axonal guidance signaling, netrin signaling, and Wnt/Ca²⁺ signaling in recovery. Our data suggest that intranasal sEV treatment could become a novel therapeutic approach for the treatment of chemobrain.

A single intranasal dose of human mesenchymal stem cell-derived extracellular vesicles after traumatic brain injury eases neurogenesis decline, synapse loss, and BDNF-ERK-CREB signaling

An optimal intranasal (IN) dose of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs), 90 min post-traumatic brain injury (TBI), has been reported to prevent the evolution of acute neuroinflammation into chronic neuroinflammation resulting in the alleviation of long-term cognitive and mood impairments. Since hippocampal neurogenesis decline and synapse loss contribute to TBI-induced long-term cognitive and mood dysfunction, this study investigated whether hMSC-EV treatment after TBI can prevent hippocampal neurogenesis decline and synapse loss in the chronic phase of TBI. C57BL6 mice undergoing unilateral controlled cortical impact injury (CCI) received a single IN administration of different doses of EVs or the vehicle at 90 min post-TBI. Quantifying neurogenesis in the subgranular zone-granule cell layer (SGZ-GCL) through 5'-bromodeoxyuridine and neuron-specific nuclear antigen double labeling at ~2 months post-TBI revealed decreased neurogenesis in TBI mice receiving vehicle. However, in TBI mice receiving EVs (12.8 and 25.6 × 10⁹ EVs), the extent of neurogenesis was matched to naive control levels. A similar trend of decreased neurogenesis was seen when doublecortin-positive newly generated neurons were quantified in the SGZ-GCL at ~3 months post-TBI. The above doses of EVs treatment after TBI also reduced the loss of pre-and post-synaptic marker proteins in the hippocampus and the somatosensory cortex. Moreover, at 48 h post-treatment, brain-derived neurotrophic factor (BDNF), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), and phosphorylated cyclic AMP response-element binding protein (p-CREB) levels were downregulated in TBI mice receiving the vehicle but were closer to naïve control levels in TBI mice receiving above doses of hMSC-EVs. Notably, improved BDNF concentration observed in TBI mice receiving hMSC-EVs in the acute phase was sustained in the chronic phase of TBI. Thus, a single IN dose of hMSC-EVs at 90 min post-TBI can ease TBI-induced declines in the BDNF-ERK-CREB signaling, hippocampal neurogenesis, and synapses.

Intranasally administered human MSC-derived extracellular vesicles inhibit NLRP3-p38/MAPK signaling after TBI and prevent chronic brain dysfunction

Traumatic brain injury (TBI) leads to lasting brain dysfunction with chronic neuroinflammation typified by nucleotide-binding domain leucine-rich repeat and pyrin domain-containing receptor 3 (NLRP3) inflammasome activation in microglia. This study probed whether a single intranasal (IN) administration of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs) naturally enriched with activated microglia-modulating miRNAs can avert chronic adverse outcomes of TBI. Small RNA sequencing confirmed the enrichment of miRNAs capable of modulating activated microglia in hMSC-EV cargo. IN administration of hMSC-EVs into adult mice ninety minutes after the induction of a unilateral controlled cortical impact injury resulted in their incorporation into neurons and microglia in both injured and contralateral hemispheres. A single higher dose hMSC-EV treatment also inhibited NLRP3 inflammasome activation after TBI, evidenced by reduced NLRP3, apoptosis-associated speck-like protein containing a CARD, activated caspase-1, interleukin-1 beta, and IL-18 levels in the injured brain. Such inhibition in the acute phase of TBI endured in the chronic phase, which could also be gleaned from diminished NLRP3 inflammasome activation in microglia of TBI mice receiving hMSC-EVs. Proteomic analysis and validation revealed that higher dose hMSC-EV treatment thwarted the chronic activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway by IL-18, which decreased the release of proinflammatory cytokines. Inhibition of the chronic activation of NLRP3-p38/MAPK signaling after TBI also prevented long-term cognitive and mood impairments. Notably, the animals receiving higher doses of hMSC-EVs after TBI displayed better cognitive and mood function in all behavioral tests than animals receiving the vehicle after TBI. A lower dose of hMSC-EV treatment also partially improved cognitive and mood function. Thus, an optimal IN dose of hMSC-EVs naturally enriched with activated microglia-modulating miRNAs can inhibit the chronic activation of NLRP3-p38/MAPK signaling after TBI and prevent lasting brain dysfunction.

Sensory neuron dysfunction in orthotopic mouse models of colon cancer

Reports of neurological sequelae related to colon cancer are largely restricted to rare instances of paraneoplastic syndromes, due to autoimmune reactions. Systemic inflammation associated with tumor development influences sensory neuron function in other disease models, though the extent to which this occurs in colorectal cancer is unknown. We induced orthotopic colorectal cancer via orthotopic injection of two colorectal cancer cell lines (MC38 and CT26) in two different mouse strains (C57BL/6 and Balb/c, respectively). Behavioral tests of pain sensitivity and activity did not detect significant alterations in sensory sensitivity or diminished well-being throughout tumor development. However, immunohistochemistry revealed widespread reductions in intraepidermal nerve fiber density in the skin of tumor-bearing mice. Though loss of nerve fiber density was not associated with increased expression of cell injury markers in dorsal root ganglia, lumbar dorsal root ganglia neurons of tumor-bearing animals showed deficits in mitochondrial function. These neurons also had reduced cytosolic calcium levels in live-cell imaging and reduced spontaneous activity in multi-electrode array analysis. Bulk RNA sequencing of DRGs from tumor-bearing mice detected activation of gene expression pathways associated with elevated cytokine and chemokine signaling, including CXCL10. This is consistent with the detection of CXCL10 (and numerous other cytokines, chemokines and growth factors) in MC38 and CT26 cell-conditioned media, and the serum of tumor-bearing mice. Our study demonstrates in a pre-clinical setting that colon cancer is associated with latent sensory neuron dysfunction and implicates cytokine/chemokine signaling in this process. These findings may have implications for determining risk factors and treatment responsiveness related to neuropathy in colorectal cancer.

Extracellular Vesicles and Acute Kidney Injury: Potential Therapeutic Avenue for Renal Repair and Regeneration

Acute kidney injury (AKI) is a sudden decline of renal function and represents a global clinical problem due to an elevated morbidity and mortality. Despite many efforts, currently there are no treatments to halt this devastating condition. Extracellular vesicles (EVs) are nanoparticles secreted by various cell types in both physiological and pathological conditions. EVs can arise from distinct parts of the kidney and can mediate intercellular communication between various cell types along the nephron. Besides their potential as diagnostic tools, EVs have been proposed as powerful new tools for regenerative medicine and have been broadly studied as therapeutic mediators in different models of experimental AKI. In this review, we present an overview of the basic features and biological relevance of EVs, with an emphasis on their functional role in cell-to-cell communication in the kidney. We explore versatile roles of EVs in crucial pathophysiological mechanisms contributing to AKI and give a detailed description of the renoprotective effects of EVs from different origins in AKI. Finally, we explain known mechanisms of action of EVs in AKI and provide an outlook on the potential clinical translation of EVs in the setting of AKI.

Assessment of sialic acid diversity in cancer- and non-cancer related CA125 antigen using sialic acid-binding Ig-like lectins (Siglecs)

This study was aimed at obtaining insight into the diversity of sialic acids in cancer- and non-cancer-related CA125 antigen, tumour marker of serous ovarian cancer. Starting from available data suggesting the possible relevance of sialic acids for discriminating CA125 antigens of different origin, we have employed a new experimental approach based on the use of human sialic acid-binding Ig-like lectins, Siglecs, as tools for the investigation of sialylation. Siglec-2, belonging to the group of evolutionarily conserved Siglecs, and Siglec-3, -6, -7, -9 and -10, which are CD33-like Siglecs, were probed in solid-phase binding assays with cancer-related CA125 antigens from pleural fluid of patients with ovarian carcinoma (pfCA125), the OVCAR-3 ovarian carcinoma cell line (clCA125) and a non-cancer-related CA125 antigen, i.e. pregnancy-associated pCA125 antigen. All Siglecs used showed detectable binding to pCA125 antigen. Siglec-3, Siglec-7 and Siglec-2 exhibited moderately stronger binding to pCA125 antigen than the others. In contrast to this, Siglec-2 and Siglec-3 preferentially recognized pfCA125 with greater total binding than for pCA125, whereas Siglec-9 and Siglec-10 were highly selective for clCA125. Siglecs promise to be powerful tools for discriminating CA125 of different origin and could propagate further research on other molecular markers of biomedical and diagnostic importance.