Discussion
With the development of experimental technology, especially electron
microscopy, it is known that in patients with CRSwNP, the patient’s
nasal mucosal epithelial cells are edema degeneration, the barrier
function of the nasal mucosa is impaired, and the resistance to harmful
substances and microorganisms is insufficient, which leads to repeated
inflammatory reactions in the nasal cavity, and then gradually lead to
the remodeling of nasal mucosa. Transmission electron microscope
observation showed that the CRSwNP tissue showed edema of nasal mucosa
epithelial cells, a large number of mitochondrial hyperplasia in the
cytoplasm, endoplasmic reticulum edema and the formation of a large
number of swallowed vesicles; Submembrane edema, dilation of small blood
vessels and capillaries in the tissue, intrinsic interstitial edema
accompanied by a large number of inflammatory
cells10-13. Also in clinical diagnosis, the most
common pathological classification of CRSwNP disease is edema polyps,
accounting for about 85%-90%.
In addition to functional endoscopic surgical resection, glucocorticoids
are widely used in clinical treatment of CRSwNP, and their therapeutic
effect has reached consensus. Local and systemic application of
glucocorticoids in the nasal cavity is considered to be effective for
the treatment of CRSwNP. Cochrane evaluation showed that glucocorticoids
can effectively improve systemic symptoms of patients with nasal polyps
and reduce edema of nasal polyps. This mechanism is proved to be that
glucocorticoid can quickly enter the cell nucleus and interact with the
glucocorticoid response element on the chromosome by binding to its
receptor, initiating or inhibiting downstream gene expression, thereby
exerting a physiological role. However, although there is a clear
understanding of the structural changes of CRSwNP tissues and cells, the
mechanism of the formation of CRSwNP tissue edema is still unclear.
According to the mechanism of glucocorticoid treatment of CRSwNP, we
tried to co-cultured CRSwNP cells with a glucocorticoid-rich medium to
observe the changes in edmea of CRSwNP, and then analyze the expression
of gene transcriptomes to compare with normal cultured CRSwNP cells.
Then we analyzed the differentially expressed genes of the two groups,
so as to predict the mechanism of nasal polyp edema is related to that
signal, while using CRISPR-Case9 gene editing technology for simple
verification.
In immunofluorescence staining of CRSwNP tissues, we found that a large
number of interstitial cells edema increased, a large number of
inflammatory cells infiltration. After the intervention of
glucocorticoid, the edema of CRSwNP cells is significantly reduced by
the difference between the CON group and the DSTG group. GO enrichment,
KEGG analysis and PPI network analysis revealed that this mechanism is
closely related to the ribosome pathway involved in RPL26. This proves
that the RPL26 gene may play an important physiological role in the
mechanism of CRSwNP cells edema.
Cell Research reported that RPL26 is the main substrate for
ubiquitination of mammalian cells and a special regulator of
ubiquitination of ribosomal proteins5. The RPL26 gene
encodes the ribosomal protein of the L24P family and is highly expressed
in the mitochondria in the cytoplasm, which can regulate mitochondrial
function. RPL26 encodes a protein that can effectively eliminate ectopic
stasis in the cell after ubiquitination, and this effect is not through
the traditional eukaryotic endoplasmic reticulum-related protein
degradation protein quality control system (ERAD) or cytosolic ribosome
The quality control (RQC) system works, but transports the accumulated
polypeptide from the endoplasmic reticulum to the lysosome in the
cytoplasm for degradation14, 15, 16.
We established RPL26 silencing and overexpressing CRSwNP cell system.
The study found that after RPL26 silencing expression, the degree of
CRSwNP tissue edema increased; but after RPL26 overexpression, CRSwNP
edema was significantly reduced. In the apoptosis experiment, no matter
whether it is RPL26 silencing system or RPL26 over-expression, there is
no significant difference in apoptosis between the two groups of
experiments and normal CRSwNP tissue. Highly expressed rpl26 can
effectively reduce the degree of cell edema and have little effect on
apoptosis. The higher apoptosis rate was detected in anti-rpl26 group,
which may be related to excessive cell edema. This result is consistent
with the results of pre-transcriptome genetic analysis, confirming that
RPL26 plays an important role in the regulation of CRSwNP tissue edema.
Using online gene annotation sites and ncbi database to query
information, the function of RPL26 may be completed through the
ribosomal signaling pathway17,18,19, but this
conjecture still needs further experimental confirmation.