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. 2019 Nov 20;24(23):4208.
doi: 10.3390/molecules24234208.

Deficiency of Urokinase Plasminogen Activator May Impair β Cells Regeneration and Insulin Secretion in Type 2 Diabetes Mellitus

Chung-Ze Wu  1   2 , Shih-Hsiang Ou  3 , Li-Chien Chang  4 , Yuh-Feng Lin  5   6 , Dee Pei  7   8 , Jin-Shuen Chen  9
Affiliations

Deficiency of Urokinase Plasminogen Activator May Impair β Cells Regeneration and Insulin Secretion in Type 2 Diabetes Mellitus

Chung-Ze Wu et al. Molecules. .

Abstract

: Background: The relationship between urokinase-type plasminogen activator (uPA) and the development of type 2 diabetes mellitus (T2DM) was investigated in the study by using mice and cell models, as well as patients with T2DM.

Methods: In mice models, wild-type and uPA knockout (uPA-/-) BALB/c mice were used for induction of T2DM. In cell models, insulin secretion rate and β cell proliferation were assessed in normal and high glucose after treating uPA siRNA, uPA, or anti-uPA antibody. In our clinical study, patients with T2DM received an oral glucose-tolerance test, and the relationship between uPA and insulin secretion was assessed.

Results: Insulin particles and insulin secretion were mildly restored one month after induction in wild-type mice, but not in uPA-/- mice. In cell models, insulin secretion rate and cell proliferation declined in high glucose after uPA silencing either by siRNA or by anti-uPA antibody. After treatment with uPA, β cell proliferation increased in normal glucose. In clinical study, patients with T2DM and higher uPA levels had better ability of insulin secretion than those with lower uPA levels.

Conclusion: uPA may play a substantial role in insulin secretion, β cell regeneration, and progressive development of T2DM. Supplementation of uPA might be a novel approach for prevention and treatment of T2DM in the future.

Keywords: insulin secretion; type 2 diabetes mellitus; urokinase plasminogen activator; β cell regeneration.

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Conflict of interest statement

The authors declare no conflicts of interest

Figures

Figure 1
Figure 1
Changes in uPA, blood glucose, body weight, uPA expression on islet, insulin, glucagon, insulin resistance (HOMA-IR), and insulin secretion (HOMA-β) before and after development of type 2 diabetes mellitus (T2DM) in both wild-type and uPA-/- mice (n ≥ 4). (A) The uPA levels in wild-type (solid line) mice were significantly higher than those in uPA-/- (dashed line) BALB/c mice. ** p < 0.01. (B) D0, blood sugar levels in both uPA-/- and wild-type mice were similar. After induction, blood glucose in uPA-/- BALB/c mice was significantly higher than in wild-type mice. *** p < 0.001. (C) The body weight in both wild-type and uPA-/- BALB/c mice showed no significant difference. (D) The expressions of uPA on islet before and after induction of T2DM were compared by immunohistochemical stain. In wild-type mice, uPA expression obviously decreased after induction of T2DM. The low expressions of uPA persisted both before and after induction in uPA-/- mice. (E) The insulin levels in wild-type mice were significantly higher than in uPA-/- mice. With the high-fat diet, insulin levels increase progressively in both wild-type and uPA-/- mice. (F) The glucagon levels declined gradually, along with elevation of insulin levels in wild-type and uPA-/- mice. (G) The HOMA-IR in wild-type mice was significantly higher than in uPA-/- mice. With a high-fat diet, the HOMA-IR increases significantly and progressively in both wild-type and uPA-/- mice. (H) The HOMA-β in uPA-/- mice was lower than in wild-type mice. After induction, the HOMA-β significantly decreases in both wild-type and uPA-/- mice. ** p < 0.01 (Kruskal–Wallis H test).
Figure 2
Figure 2
Hematoxylin and eosin (H&E), and immunohistochemical (IHC) stain of glucagon, insulin, and proliferating cell nuclear antigen (PCNA) on islet before and after induction of type 2 diabetes mellitus in wild-type and uPA-/- mice and after treatment with uPA plasmids in uPA-/- mice. (A) The H&E stain of islet showed no pathologic structural change in either wild-type or uPA-/- mice. The expression of glucagon on islet increased after induction both in wild-type and uPA-/- mice. Obviously, insulin particles of islet 30 days after induction (D30) increased in wild-type mice as compared with uPA-/- mice. Meanwhile, the PCNA expression of islet increased on D30 in wild-type mice. After treatment with uPA plasmids in uPA-/- mice, the glucagon, insulin, and PCNA expressions are similar to those on D30 in wild-type mice. (B) The quantitative intensity score of expression of glucagon, insulin, and PCNA on islets on induction day (D0), D3, and D30, after induction was assessed and scored by pathologists. The intensity scores of glucagon in uPA-/- mice were significantly higher than those in wild-type mice on D3. The intensity scores of insulin in wild-type mice were significantly higher than those in uPA-/- mice on D3 and D30. The intensity score of PCNA in wild-type mice on D30 was higher, but did not reach statistical significance. ** p < 0.01 (Kruskal–Wallis H test).
Figure 3
Figure 3
Changes in uPA, body weight, and blood glucose in uPA-/- mice treated with uPA plasmids. The uPA-/- mice were treated with intramuscular injection of uPA plasmids (blank circle) or control plasmid (black circle) weekly. The uPA, body weight, and blood glucose were measured (n = 6). (A) The uPA levels significantly increased after treatment with uPA plasmid in uPA-/- mice. (* p < 0.05) (B) Body weight during the whole experiment showed no significant change in the two groups. (C) Blood sugar did not elevate after induction, but mice injected with control plasmid developed hyperglycemia. In other words, no uPA-/- mouse developed T2DM after treatment with uPA plasmids (Mann–Whitney U test).
Figure 4
Figure 4
The (A) uPA secretion rate and expression on β cells; (B) insulin secretion rate, in normal glucose or high glucose; and (C) β cell proliferation in high glucose (n = 6). (A) The uPA secretion rate of β cells in normal glucose (black bar) was significantly faster than those in high glucose (white bar) treated for both 24 and 48 h. *** p < 0.001. The uPA expression on β cells significantly declined after treatment with high glucose for 48 h. * p < 0.05 (Mann–Whitney U test) (B) The insulin secretion rate in normal glucose showed no significant difference among control (black circle), S-siRNA (blank circle) or uPA siRNA (inversed triangle) groups. After silencing uPA by siRNA, the insulin secretion rate of β cells decelerated significantly in high glucose. ** p < 0.01. (Kruskal–Wallis H test) (C) β cell proliferation is evaluated by MTT assay while incubated in high glucose for 48 h. After silencing uPA expression by siRNA (white bar), the β cell proliferation significantly decreased in high glucose as compared with control (black bar) and S-siRNA groups (gray bar). * p < 0.05 (Kruskal–Wallis H test).
Figure 5
Figure 5
Insulin secretion rate and β cell proliferation in normal glucose or high glucose after treating with uPA or anti-uPA antibody. (A) Insulin secretion rate of β cells treated with control (black circle), uPA (blank circle), anti-uPA antibody (inverted black triangle), or uPA + anti-uPA antibody (blank triangle). In normal glucose, the insulin secretion rate of β cells with treating uPA antibody significantly decreased at 2 h. However, the insulin recreation rate at 4 h significantly increased after treating uPA and co-treating uPA and uPA antibody. The insulin secretion rate of β cells significantly decelerated in high glucose, after being treated with uPA antibody. * p < 0.05, ** p < 0.01 as compared with control group (Kruskal–Wallis H test). (B) Proliferation of β cells treated with uPA, anti-uPA antibody, or uPA + anti-uPA antibody for 24 or 48 h. The β cell proliferation increased after being treated with uPA in normal glucose. In high glucose, β cell proliferation decreased after being treated with anti-uPA antibody. * p < 0.05 (Kruskal–Wallis H test).
Figure 6
Figure 6
The correlation between uPA and insulin secretion in patients with T2DM. (A) The uPA levels showed a weak and significant linear relationship with insulin secretion in patients with T2DM. (r = 0.308, p = 0.001; Pearson’s correlation) (B) Patients with T2DM were divided into quartiles according to uPA level. The patients with the highest quartile of uPA (uPA4) showed better ability of insulin secretion than those in the other three groups (uPA1-3). However, there was no significant difference among the other three groups. *** p < 0.001 (One-way ANOVA with Bonferroni post hoc test).
Figure 7
Figure 7
A model of uPA deficiency leading to development of T2DM. According to our results, we propose a possible model of development of T2DM following uPA deficiency. Numerous genetic and environmental factors contribute to uPA deficiency in some people. The uPA deficiency, in turn, contributes to both insulin secretion impairment and poor β cell regeneration. These two factors, plus insulin resistance, lead to hyperglycemia. Hyperglycemia suppresses uPA expression in islet. The vicious cycle of β cell failure is established on uPA deficiency. Finally, T2DM develops, and patients will need insulin supplementation eventually. Thus, our model might point the way for early detection and treatment of T2DM.
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References

    1. Levy J., Atkinson A.B., Bell P.M., McCance D.R., Hadden D.R. Beta-cell deterioration determines the onset and rate of progression of secondary dietary failure in type 2 diabetes mellitus: The 10-year follow-up of the belfast diet study. Diabet. Med. 1998;15:290–296. doi: 10.1002/(SICI)1096-9136(199804)15:4<290::AID-DIA570>3.0.CO;2-M. - DOI - PubMed
    1. U.K. Prospective diabetes study 16. Overview of 6 years’ therapy of type II diabetes: A progressive disease. U.K. Prospective diabetes study group. Diabetes. 1995;44:1249–1258. doi: 10.2337/diab.44.11.1249. - DOI - PubMed
    1. Ahrén B. Type 2 diabetes, insulin secretion and beta-cell mass. Curr. Mol. Med. 2005;5:275–286. doi: 10.2174/1566524053766004. - DOI - PubMed
    1. Butler A.E., Janson J., Bonner-Weir S., Ritzel R., Rizza R.A., Butler P.C. Beta-cell deficit and increased beta-cell apoptosis in humans with type 2 diabetes. Diabetes. 2003;52:102–110. doi: 10.2337/diabetes.52.1.102. - DOI - PubMed
    1. Grant P.J. Diabetes mellitus as a prothrombotic condition. J. Intern. Med. 2007;262:157–172. doi: 10.1111/j.1365-2796.2007.01824.x. - DOI - PubMed

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