Lacticaseibacillus casei AMBR2 Restores Airway Epithelial Integrity in Chronic Rhinosinusitis With Nasal Polyps

Abstract

Purpose A defective epithelial barrier has been demonstrated in chronic rhinosinusitis with nasal polyps (CRSwNP). Lactobacilli are shown to restore epithelial barrier defects in gastrointestinal disorders, but their effect on the airway epithelial barrier is unknown. In this study, hence, we evaluated whether the nasopharyngeal isolates Lacticaseibacillus casei AMBR2 and Latilactobacillus sakei AMBR8 could restore nasal epithelial barrier integrity in CRSwNP. Methods Ex vivo trans-epithelial tissue resistance and fluorescein isothiocyanate-dextran 4 kDa (FD4) permeability of nasal mucosal explants were measured. The relative abundance of lactobacilli in the maxillary sinus of CRSwNP patients was analyzed by amplicon sequencing of the V4 region of the 16S rRNA gene. The effect of spray-dried L. casei AMBR2 and L. sakei AMBR8 on epithelial integrity was investigated in vitro in primary nasal epithelial cells (pNECs) from healthy controls and patients with CRSwNP as well as in vivo in a murine model of interleukin (IL)-4 induced barrier dysfunction. The activation of Toll-like receptor 2 (TLR2) was explored in vitro by using polyclonal antibodies. Results Patients with CRSwNP had a defective epithelial barrier which positively correlated with the relative abundance of lactobacilli-specific amplicons in the maxillary sinus. L. casei AMBR2, but not L. sakei AMBR8, increased the trans-epithelial electrical resistance (TEER) of pNECs from CRSwNP patients in a time-dependent manner. Treatment of epithelial cells with L. casei AMBR2 promoted the tight junction proteins occludin and zonula occludens-1 reorganization. Furthermore, L. casei AMBR2 prevented IL-4-induced nasal permeability in vivo and in vitro. Finally, the beneficial effect of L. casei AMBR2 on nasal epithelial cells in vitro was TLR2-dependent as blocking TLR2 receptors prevented the increase in TEER. Conclusions A defective epithelial barrier in CRSwNP may be associated with a decrease in relative abundance of lactobacilli-specific amplicons. L. casei AMBR2 would restore nasal epithelial integrity and can be a novel therapeutic strategy for CRSwNP.

The nasal mutualist Dolosigranulum pigrum AMBR11 supports homeostasis via multiple mechanisms

“…To the best of our knowledge, documentation on such barrier-enhancing effects on the URT epithelium is scarce. Recently, we have also found barrier-protective effects for the URT isolate L. casei AMBR2 ( Martens et al., 2021 ). Notably, compared to D. pigrum , L. casei has a weaker association with the nose as its main habitat based on its lower prevalence and relative abundance in the URT ( De Boeck et al., 2020 ) and its association with more habitats as nomadic species ( Duar et al., 2017 ).…”

“…Both immune signaling and pathogen killing likely play a role in the beneficial action of D. pigrum ; however, understanding the detailed role of each of these mechanisms would require detailed dedicated research at the molecular level. TLR activation by D. pigrum was also explored in the present study, as these receptors are involved in epithelial barrier functioning, with TLR2/6 activation generally linked to barrier-enhancing and anti-inflammatory signaling effects; however, TLR2/1 is rather involved in inflammation and barrier-disruptive effects ( Martens et al, 2021 , 2021 ; Yuki et al., 2011 ). We observed that D. pigrum strongly activated the TLR2/TLR6 heterodimer, even stronger than L. casei AMBR2 ( Martens et al., 2021 ) and S. aureus, the latter mainly inducing TLR1/6.…”

“…This order of lactic acid bacteria (LAB) encompasses taxa from the family of the Lactobacillaceae , including well-characterized lactobacilli ( De Boeck et al., 2020 ), and from the family of Carnobacteriaceae ( Lawson and Caldwell, 2014 ), especially the species Dolosigranulum pigrum ( De Boeck et al., 2019 ). Compared to (nasal) lactobacilli that could be cultured and studied in lab, animal and even in human trials ( De Boeck et al., 2020 ; Martens et al., 2021 ; De Rudder et al., 2020 ), nasal Carnobacteriaceae turned out to be more difficult to culture and study at functional level. D. pigrum was only first described in 1993 as a Gram-positive, catalase-negative bacterium and potentially opportunistic pathogen ( Aguirre et al., 1993 ).…”

Evaluation of a throat spray with lactobacilli in COVID-19 outpatients in a randomized, double-blind, placebo-controlled trial for symptom and viral load reduction

“…Moreover, an alternative formulation such as a nose spray instead of the used throat spray, might be more favorable, since SARS-CoV-2 receptors are highly expressed in nasal epithelium, and the alpha variant that was dominant during the study has been shown to primarily target the nose [27]. In addition, based on in-house previous research, the selected lactobacilli have several beneficial modes of action such as antimicrobial and immunomodulatory properties, as well as barrier enhancing effects in the nasal epithelium [28][29][30].…”

Effect ofLacticaseibacillus caseiAMBR2 on Epithelial Barrier Function in Chronic Rhinosinusitis With Nasal Polyps

“…In the current issue, Martens et al . 7 aimed to investigate the effect of Lacticaseibacillus casei AMBR2 ( L. casei AMBR2) on nasal epithelial barrier function of human primary nasal epithelial cells (pNECs) in CRSwNP patients. They also reported that the anterior nares and nasopharynx of CRSsNP and CRSwNP patients had significantly low relative abundance of lactobacilli compared to controls.…”