Wei Wensheng's team from Peking University reported on the new Clostridium difficile toxin B receptor

Clostridioides difficile (Clostridioides difficile) infection is one of the most important causes of iatrogenic infections worldwide [1]
.

It can cause fever, diarrhea, pseudomembranous enteritis, intestinal perforation, and even sepsis, shock and other life-threatening symptoms [2]
.

Clostridium difficile causes damage to host cells by secreting two similarly structured toxins A and B (TcdA and TcdB)
.

Clostridial toxins contain a repetitive sequence at the carboxyl end, which is called combined repetitive oligopeptides (CROPs)
.

Early studies found that CROPs protein can competitively inhibit the binding of Clostridium difficile toxins to cells, and antibodies against the CROPs region can prevent Clostridium difficile toxins from exerting cytotoxicity [3,4].
Therefore, Clostridium difficile toxins may be dependent on CROPs.
The receptor is introduced into the cell
.

With the application of gene editing technology in the study of Clostridium difficile receptors, chondroitin sulfate proteoglycan 4 (CSPG4), Frizzled-1/2/7 and other proteins have been found to be receptors that mediate the entry of TcdB toxin into cells [5 ,6]
.

However, these receptors mainly mediate their endocytosis by interacting with non-CROPs regions of TcdB.
It is still unclear whether TcdB has CROPs-dependent receptors
.

At the same time, the combined knockout of known receptors still cannot prevent high concentrations of TcdB toxin from entering the cell, suggesting the existence of unknown new receptors
.

Recently, the team of Professor Wei Wensheng from the School of Life Sciences of Peking University published a research paper entitled "Low-density lipoprotein receptor-related protein 1 is a CROPs associated receptor for Clostridioides difficile toxin B" in Science China Life Sciences
.

The study found that low-density lipoprotein receptor-related protein 1 (LRP1) is a CROPs-dependent C.
difficile toxin B receptor
.

In this study, the researchers designed and synthesized a subgenomic sgRNA library targeting approximately 3,000 membrane protein-related genes, and performed CRISPR screening for TcdB entry into cells
.

Since the redundancy of the C.
difficile toxin receptor has brought great difficulties to the discovery of unknown receptors, in order to reduce the interference caused by the redundancy of the TcdB receptor on the screening, the researchers chose to use the CSPG4 knockout cell line.
Screening for unknown TcdB receptors
.

In the end, the screening resulted in the candidate gene LRP1 of the TcdB receptor
.

Subsequent studies have verified the biological function of LRP1 in mediating the entry of C.
difficile toxin into cells through gene knockout and gene up-regulation methods
.

Interestingly, unlike CSPG4 and Frizzled-2, the interaction between LRP1 and TcdB is mainly mediated by CROPs
.

Knockout of LRP1 in the CSPG4 and FZD2 double knockout cell lines can further improve the cell's tolerance to TcdB, indicating that the three receptor functions are redundant
.

This study found the TcdB receptor on which CROPs depend for the first time, and confirmed the role of the CROPs region in mediating TcdB and cell membrane surface receptors, thus further improving the molecular mechanism of C.
difficile toxin entry into the cell, and for the treatment of C.
difficile infections Provides potential targets and theoretical basis
.

LRP1 knockout enhances cell TcdB tolerance and multi-receptor-mediated TcdB infiltration model, Dr.
Guo Shengjie, School of Life Sciences, Peking University, is the first author of the paper, and Professor Wei Wensheng and Associate Researcher Zhou Zhuo are the co-corresponding authors of the paper, Beijing Dr.
Chen Yiou, Dr.
Liu Jingze, Dr.
Liu Zhiheng, and doctoral student Zhang Xinyi also participated in the research work
.

[References] [1] Martin, JSH, Monaghan, TM & Wilcox, MH Clostridium difficile infection: epidemiology, diagnosis and understanding transmission.
Nat Rev Gastro Hepat 13, 206-216, doi:10.
1038/nrgastro.
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25 (2016).
[2] Rupnik, M.
, Wilcox, MH & Gerding, DN Clostridium difficile infection: new developments in epidemiology and pathogenesis.
Nature reviews.
Microbiology 7, 526-536, doi:10.
1038/nrmicro2164 (2009).
[3] Frey, SM & Wilkins, TD Localization of two epitopes recognized by monoclonal antibody PCG-4 on Clostridium difficile toxin A.
Infection and immunity 60, 2488-2492 (1992).
[4] Sauerborn, M.
, Leukel, P.
& von Eichel- Streiber, C.
The C-terminal ligand-binding domain of Clostridium difficile toxin A (TcdA) abrogates TcdA-specific binding to cells and prevents mouse lethality.
FEMS microbiology letters 155, 45-54,doi:Doi 10.
1016/S0378-1097(97)00365-0 (1997).
[5] Yuan, P.
et al.
Chondroitin sulfate proteoglycan 4 functions as the cellular receptor for Clostridium difficile toxin B.
Cell research 25, 157-168 , doi:10.
1038/cr.
2014.
169 (2015).
[6] Tao, L.
et al.
Frizzled proteins are colonic epithelial receptors for C.
difficile toxin B.
Nature 538, 350-355, doi:10.
1038/nature19799 (2016) .
For details of the research, please read the original text▼[click the link below or read the original text] Guo, S.
, Chen, Y.
, Liu, J.
, Zhang, X.
, Liu, Z.
, Zhou, Z.
, and Wei, W.
(2021).
Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides difficile toxin B.
Sci China Life Sci 64,https://doi.
org/10.
1007/s11427-021-1943-9Cell research 25, 157-168, doi:10.
1038/cr.
2014.
169 (2015).
[6] Tao, L.
et al.
Frizzled proteins are colonic epithelial receptors for C.
difficile toxin B.
Nature 538, 350-355, doi :10.
1038/nature19799 (2016).
For details of the research, please read the original text▼[click the link below or read the original text] Guo, S.
, Chen, Y.
, Liu, J.
, Zhang, X.
, Liu, Z.
, Zhou, Z .
, and Wei, W.
(2021).
Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides difficile toxin B.
Sci China Life Sci 64,https://doi.
org/10.
1007/s11427- 021-1943-9Cell research 25, 157-168, doi:10.
1038/cr.
2014.
169 (2015).
[6] Tao, L.
et al.
Frizzled proteins are colonic epithelial receptors for C.
difficile toxin B.
Nature 538, 350-355, doi :10.
1038/nature19799 (2016).
For details of the research, please read the original text▼[click the link below or read the original text] Guo, S.
, Chen, Y.
, Liu, J.
, Zhang, X.
, Liu, Z.
, Zhou, Z .
, and Wei, W.
(2021).
Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides difficile toxin B.
Sci China Life Sci 64,https://doi.
org/10.
1007/s11427- 021-1943-9Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides difficile toxin B.
Sci China Life Sci 64,https://doi.
org/10.
1007/s11427-021-1943-9Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides difficile toxin B.
Sci China Life Sci 64,https://doi.
org/10.
1007/s11427-021-1943-9