Objective

2

To investigate whether liver kinase B1 (LKB1) influences airway inflammation in allergic asthma by affecting the polarization of alveolar macrophages (AMs).

Methods

2

Twenty female BALB/c mice were randomly divided into four groups: control group

asthma group

siRNA (si⁃LKB1) intervention group

and mismatched siRNA control group

with five mice in each group. The mouse model of acute allergic asthma was established by sensitization with ovalbumin (OVA). One day before sensitization

si⁃LKB1 and mismatched siRNA were injected into the mice via the tail vein

respectively. After continuous stimulation for 3 days

alveolar lavage fluid and lung tissue were collected for detection. Western Blot was used to detect the expression level of LKB1 in mouse lung tissue; qPCR was used to detect the mRNA level in mouse lung tissue to verify the knockdown effect of siRNA; HE and PAS staining were performed to evaluate inflammation and injury in mouse lung tissues; Flow cytometry was used to detect the levels of cytokines and AMs polarization phenotype in bronchoalveolar lavage fluid.

Results

2

In the lung tissues of mice with allergic asthma

the expression of LKB1 significantly increased by approximately 1.84 times as compared with the control group. Inhibiting LKB1 led to increased inflammatory cell infiltration

more pronounced thickening of the bronchial walls

and noticeable hyperplasia of goblet cells

as observed through HE and PAS staining. Compared with those in the asthma group

knocking down LKB1 resulted in elevated levels of TNF⁃α （(298.36±22.18） pg·mL

-1

vs

（218.78±35.83）

pg·mL

-1

） and IL⁃4 (（26.70±0.87） pg·mL

-1

vs

（21.45±0.82) pg·mL

-1

) in alveolar lavage fluid; meanwhile

IL⁃10 （(9.02±1.27） pg·mL

-1

v

s (19.26±0.75） pg·mL

-1

) decreased. The proportion of AMs the alveolar lavage fluid increased as (18.57±0.73）%

vs

(7.49±0.81%)

and the proportion of M1 type macrophages to AMs increased as (63.40±1.49)%

vs

(23.16±2.10)%.

Conclusion

2

LKB1 can inhibit the polarization of AMs towards M1 and alleviate allergic asthma airway inflammation. Inhibiting LKB1 expression can upregulate the expression of pro⁃inflammatory factors such as TNF⁃α and IL⁃4 in the airway

promote the aggregation of AMs in the airway and their polarization towards M1

and exacerbate allergic asthma airway inflammation.