Biology subjects

Gustafsson, J. K.

Publications and source records attributed to Gustafsson, J. K..

4 recordsLinked to original sources

bioRxiv2026

Citrobacter rodentium infection disrupts colonic mucus barrier function via ablation of intercrypt goblet cells

The colonic mucus barrier, composed of distinct layers maintained by specialized goblet cell (GC) subtypes, forms the first line of defense against enteric pathogens. However, the individual contributions of inner (IML) and fecal (FML) mucus layers to barrier integrity, and how these layers and the GC responses are dynamically modulated during infection remain incompletely understood. Using Citrobacter rodentium infection in mice, we show that early colonization disrupts the inner mucus layer, increases mucus penetrability and drives alterations in faecal mucus layer thickness. Spatial imaging revealed progressive crypt infiltration and concurrent accumulation of pathogen clusters within the FML. Transcriptomic and functional analyses identified Spdef-dependent intercrypt goblet cells (icGCs) as essential for sustaining IML integrity and limiting epithelial access. Spdef-deficient mice exhibited delayed clearance and enhanced crypt invasion, highlighting the protective role of icGCs. Infection selectively depleted icGCs, collapsing the intercrypt mucus and creating permissive niches for colonization. Mechanistically, C. rodentium leveraged its type III secretion system, specifically the EspF effector to reprogram GC transcriptional responses, inducing metabolic stress and promoting apoptotic signatures in GCs specifically. These findings reveal a previously unrecognized virulence strategy in which EspF-driven GC remodeling compromises intercrypt mucus defenses, potentially facilitating pathogen persistence and transmission.

microbiology↗

bioRxiv2025

Degradation of the intestinal mucus layer by the ETEC protease EatA is species specific determined by the structure of the MUC2 mucin

Enterotoxigenic Escherichia coli (ETEC) infections are a leading cause of diarrheal illness, responsible for an estimated 100,000 deaths annually. ETEC pathogenesis is driven by various virulence factors, including toxins, adhesins, and noncanonical factors such as the protease EatA. The first line of host defense against intestinal pathogenic bacterial infections is the protective intestinal mucus layer. Here, we demonstrate the mechanism by which EatA facilitates access to the epithelial cell surface by degrading the core mucus component MUC2, thereby aiding to the infection. We identify the specific cleavage site region localized at the C-terminal of MUC2. EatAs protease activity depends on the interaction between two distinct domains, which are uniquely spaced in human MUC2, contributing to species specificity. This was confirmed using a novel chimeric mouse model solely expressing human MUC2, which allowed us to study the role of the mucus layer in the infection of human intestinal pathogens. These findings highlight how ETEC has adapted to specifically degrade the mucus layer of its human host.

molecular biology↗

bioRxiv2024

Anion exchange regulates intestinal mucus expansion while Cftr regulates de novo mucus secretion

The intestinal epithelium is covered by mucus that protects the tissue from the luminal content. Studies have shown that anion secretion via the cystic fibrosis conductance regulator (Cftr) regulates mucus formation in the small intestine. However, mechanisms regulating mucus formation in the colon are less understood. The aim of this study was to explore the role of anion transport in regulation of mucus formation during steady state, and in response to carbamylcholine (CCh) and prostaglandin E2 (PGE2). Cftr{Delta}F508 (CF) mice were used to assess the role of Cftr, and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) was used to inhibit anion exchange. In the distal colon, steady state mucus expansion was reduced by apical DIDS, and normal in CF mice. PGE2 stimulated mucus expansion without de novo mucus secretion in wild type (WT) and CF distal colon via DIDS sensitive mechanisms, while CCh induced de novo mucus secretion in WT but not in CF colon. However, when added simultaneously, CCh and PGE2, stimulated de novo mucus secretion in CF colon via DIDS sensitive pathways. A similar response was observed in CF ileum that responded to CCh and PGE2 with DIDS sensitive de novo mucus secretion. In conclusion, this study suggests that apical anion exchange regulates intestinal mucus expansion, while Cftr regulates de novo mucus secretion from ileal and distal colon crypts. Furthermore, these findings demonstrate that in the absence of a functional Cftr channel, activation of anion exchange can help release mucus from intestinal goblet cells.

physiology↗

bioRxiv2020

Goblet cell LRRC26 regulates BK channel activation and protects against colitis in mice

Goblet cells (GCs) are specialized cells of the intestinal epithelium contributing critically to mucosal homeostasis. One of the functions of GCs is to produce and secrete MUC2, the mucin that forms the scaffold of the intestinal mucus layer coating the epithelium and separates the luminal pathogens and commensal microbiota from the host tissues. Although a variety of ion channels and transporters are thought to impact on MUC2 secretion, the specific cellular mechanisms that regulate GC function remain incompletely understood. Previously, we demonstrated that leucine-rich-repeat-containing protein 26 (LRRC26), a known regulatory subunit of the Ca2+-and voltage-activated K+ channel (BK channel), localizes specifically to secretory cells within the intestinal tract. Here, utilizing a mouse model in which MUC2 is fluorescently tagged allowing visualization of single GCs in intact colonic crypts, we show that murine colonic GCs have functional LRRC26-associated BK channels. In the absence of LRRC26, BK channels are present in GCs, but are not activated at physiological conditions. In contrast, all tested MUC2-negative cells completely lacked BK channels. Moreover, LRRC26-associated BK channels underlie the BK channel contribution to the resting transepithelial current across mouse distal colonic mucosa. Genetic ablation of either LRRC26 or BK-pore forming -subunit in mice results in a dramatically enhanced susceptibility to colitis induced by dextran sodium sulfate (DSS). These results demonstrate that normal potassium flux through LRRC26-associated BK channels in GCs has protective effects against colitis in mice. SignificanceA primary function of goblet cells (GCs) of the intestinal epithelium is to generate a protective mucus layer lining the intestinal lumen. GC dysfunction is linked to Inflammatory Bowel Disease (IBD). GC mucus secretion is thought to be dependent on contributions of an ensemble of anion and cation fluxes, although understanding remains limited. Here, it is shown in mouse colon that the Ca2+- and voltage-dependent BK-type K+ channel, specifically in association with the LRRC26 regulatory subunit, plays a critical role in normal GC function, protecting mice against chemically-induced colitis. The results demonstrate that normal K+ fluxes mediated by LRRC26-containing BK channels are required for normal GC function, potentially providing insights into the potential role of BK channels in IBD.

physiology↗