The distribution of renal hyaluronan and the expression of hyaluronan synthases during water deprivation in the Spinifex hopping mouse, Notomys alexis

Correlation between hyaluronic acid,hyaluronic Acid synthase and human renal clear cell carcinoma

OBJECTIVE

To study the correlation between hyaluronic acid (HA), hyaluronic acid synthase (HAS) and human renal clear cell carcinoma (RCCC).

METHODS

The expression of three HAS isoforms' gene and HA in 93 RCCC tissues, 27 nephridial tissues by the side of RCCC from two hospitals were measured with Real-Time RT-PCR、Western Blot and immunohistochemical methods and analyzed.

RESULTS

All RCCC and adjacent normal tissues expressed three HASs' mRNA & protein; at the mRNA level, both RCCC and adjacent normal tissues, expressed more HAS3 than HAS1 or HAS2, their differences were statistically significant (all P values <0.05); but, at the protein level, all HAS isoforms presented the equivalent expression. Compared with the adjacent non-neoplastic kidney tissues, the expression of all HAS isoforms' mRNA in RCCC tissues were increased evidently and their differences were significant (all P values <0.0001); but at the protein level, only the expression of HAS3 increased evidently (P=0.022). In all adjacent normal tissues, more than 80% renal tubular cells strongly expressed HA, however, only the minority RCCC cases (16/93) presented weakly positive HA staining in few cancer nests (5%-30%), the difference were significant (P<0.0001). In RCCC tissues subgrouped according to clinical stage, pathological grade, lymphatic metastasis or not and distant metastasis or not, the HASs' mRNA & protein differential expression all had no statistical significance (all P values >0.05).

CONCLUSION

Different from other malignancy, HA and HASs (except for HAS3) may not play important roles in the biological progress of human RCCC.

Angiotensin converting enzyme inhibition blocks interstitial hyaluronan dissipation in the neonatal rat kidney via hyaluronan synthase 2 and hyaluronidase 1

A functional renin-angiotensin system (RAS) is required for normal kidney development. Neonatal inhibition of the RAS in rats results in long-term pathological renal phenotype and causes hyaluronan (HA), which is involved in morphogenesis and inflammation, to accumulate. To elucidate the mechanisms, intrarenal HA content was followed during neonatal completion of nephrogenesis with or without angiotensin converting enzyme inhibition (ACEI) together with mRNA expression of hyaluronan synthases (HAS), hyaluronidases (Hyal), urinary hyaluronidase activity and cortical lymphatic vessels, which facilitate the drainage of HA from the tissue. In 6-8days old control rats cortical HA content was high and reduced by 93% on days 10-21, reaching adult low levels. Medullary HA content was high on days 6-8 and then reduced by 85% to 12-fold above cortical levels at day 21. In neonatally ACEI-treated rats the reduction in HA was abolished. Temporal expression of HAS2 corresponded with the reduction in HA content in the normal kidney. In ACEI-treated animals cortical HAS2 remained twice the expression of controls. Medullary Hyal1 increased in controls but decreased in ACEI-treated animals. Urine hyaluronidase activity decreased with time in control animals while in ACEI-treated animals it was initially 50% lower and did not change over time. Cells expressing the lymphatic endothelial mucoprotein podoplanin in ACEI-treated animals were increased 18-fold compared to controls suggesting compensation. In conclusion, the high renal HA content is rapidly reduced due to reduced HAS2 and increased Hyal1 mRNA expressions. Normal angiotensin II function is crucial for inducing these changes. Due to the extreme water-attracting and pro-inflammatory properties of HA, accumulation in the neonatally ACEI-treated kidneys may partly explain the pathological renal phenotype of the adult kidney, which include reduced urinary concentration ability and tubulointerstitial inflammation.