Human epidermal growth factor receptor 2 (HER2) is a cell surface receptor tyrosine kinase that belongs to the HER family. HER2 overexpression in human prostate cancer has been frequently observed; however, there are no reports on HER2 expression in canine prostate carcinoma (PC). The purpose of this study was to investigate HER2 expression and the underlying molecular mechanisms in canine PC. Twenty-one formalin-fixed paraffin-embedded canine prostate gland tissues (13 carcinomas and 8 normal controls) were analyzed for HER2 expression using immunohistochemistry. Using a digital polymerase chain reaction assay, the HER2 copy number in 8 PC and 6 normal prostate gland tissues was determined. HER2 overexpression occurred in 8/13 (61.5%) PC cases, but not in the normal controls. There were no significant associations between HER2 overexpression and clinical characteristics of the PC cases, such as age, neuter status, lymph node involvement, distant metastasis, and overall survival. HER2 copy number gain (CNG) was detected in 3/8 (37.5%) PC cases, but not in the normal controls. All PC cases with HER2 CNG exhibited HER2 overexpression, suggesting that HER2 CNG may lead to HER2 overexpression. These findings provide new insights into the molecular pathogenesis of canine PC; these may be therapeutically relevant. Dogs with PC would be useful as a preclinical large animal model for the development of new therapy for HER2-overexpressing prostate cancer in humans.

Inositol polyphosphate 5-phosphatase K (INPP5K) is an endoplasmic reticulum (ER)-residing phosphoinositide 5-phosphatase that de-phosphorylates PI(4,5)P₂, thereby regulating ER morphology. Here, we show that INPP5K interacts with β-tubulin through its 5-phosphatase domain and localizes to microtubules. A cluster of basic amino acids within the 5-phosphatase domain of INPP5K is responsible for this interaction. Alteration of these amino acids to alanine (INPP5K 4A mutant) abolished INPP5K localization to the ER. Expression of the INPP5K 4A mutant induced ER swelling and the withdrawal of ER tubules. Taken together, these findings suggest that INPP5K connects the ER to microtubules and regulates ER morphology.

In humans, pulse rate variability (PRV) obtained from pulse waves (PWs) is utilized to assess cardiac autonomic nervous function which normally heart rate variability (HRV) obtained from inter-beat (RR) intervals of an electrocardiogram (ECG) recording represents. However, the acceptability of PRV as an index of autonomic function in rats has not been evaluated and, therefore, was the aim of the present study. PW and ECG waveforms of normotensive Sprague Dawley (SD) rats and Spontaneously Hypertensive Rats (SHR) were recorded using photoplethysmography of the tail and radiotelemetry. The frequency component in a series of intervals between the maximum points of the second derivative photoplethysmography waveform or between the RR intervals of the ECG waveform was analyzed using the Cooley–Tukey fast Fourier transform algorithm and the correlativity of the low frequency (LF) power, high-frequency (HF) power, and LF/HF ratio were determined. The R-values for the coefficients of determination between parameters from HRV and PRV were above 0.98 in both normotensive and hypertensive rats, indicating that these two analyses provide the same results. Our findings suggest that the PRV method may be an alternative to HRV in rats with hypertension to effectively evaluate autonomic nerve function in drug discovery research. Since oscillometric tail-cuff BP analyses in rats are commonly used in pharmaceutical research, the PRV would provide additional valuable information on cardiac autonomic nervous function during the evaluation of drug efficacy and safety.

In vivo assessment of murine gastrointestinal (GI) motility is useful for understanding GI diseases and developing effective therapies. The establishment of noninvasive measurement methods for mice will contribute to translational research bridging basic research and clinical practice, which can be a beneficial for maintaining quality of life in humans and animals. Recent advances in noninvasive diagnostic techniques have led to this update on the application and performance of available tests in mice. In vivo imaging techniques have been developed as noninvasive methods for the assessment of murine GI motility, and many of these methods have been applied to humans. Imaging techniques, including scintigraphy and ultrasonography, are frequently used in clinical practice. Basic data obtained using methods commonly used in clinical practice may be directly translated to clinical practice and are more attractive than those obtained using invasive methods. In this review, we provide recommended methods for noninvasively investigating gastric, small intestinal, and colonic motility in mice and detail the benefits of each test.